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User Manual - LinearX Systems Inc

1. 120 150 180 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Curve Averaging Curve Compare Binary Math Operations Operatio Mul Results A B Div Result A B Library Curve Operand b D25 at 2M OperandB 9 P25 1M Tails Result 26 C13 Packed LMS 4 1 User Manual Processing Menu 7 2 Binary Math Operations ARIS RA lud RB AB AE The Processing Binary Math Operations menu item will open a dialog which performs basic arithmetic operations on a pair of curves The tool button as shown above on the Processing toolbar can also be used to activate this item Binary math operations involve two curves hence the term binary The two operand curves are library curves and the result is placed into a different library curve entry The result curve will be given a default name which denotes the operation performed The fundamental operations of mul div add and sub can be performed on the two operand curves The frequency ranges in the two
2. 3 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K LMS 4 1 User Manual Chapter 15 Impedance Applications A listing of the final speaker parameters is now shown below The units of the various parameters will be based on your choices in the dialog F ox Loudspeaker Measurement System LMS TM 4 0 0 232 Jul 04 2000 C opyright 1993 2000 by LinearX Systems Inc ElectroMech Speaker Parameters Jul 5 2000 Wed 1 48 pm Library 121399 11b Reference Curve 15 FA Revc 3 12 Delta M C Curve 15 45GRAMS Revc 3 12 Method Double Curve Delta Mass Domain FreeAir Model LEAP4 Revc 3 120 Ohm Fo 37 747 Hz Sd 85 600m sqM Krm 4 556m Ohm Erm 0 701 Kxm 10 726m Ohm Exm 0 689 Vas 261 929m Cms 251 737u M N Mmd 56 221m Kg Mms 70 622 g BL 11 401 TM Oms 3 775 Qes Ots 0 402 0 363 No 3 400 SPLo 97 318 dB LMS 4 1 User Manual End 319 Impedance Applications Chapter 15 320 LMS 4 1 User Manual Misc Applications Chapter 16 16 t Applications ISC Help essing Utilities Scale View ToolBars Control Graph Node Show Snap View Help Ej meae ala HH ala Do 2 File Graph Analyzer Proc Capacitance vs OE EN EN EN EEEL
3. 100 200 500 1K 20K Near field measurements of Woofer and Port LMS 4 1 285 User Manual SPL Applications Chapter 14 If a low range limit of 10Hz had been used this may not have been necessary The minimum phase was then generated This is shown in the bottom graph To combine the woofer and port curves the SUBtract process operation is used The curves must be subtracted because the port wave is out of phase with that of the speaker 27 SPL vs Freq Scaled Woofer and Port curves to 1 Meter SPL vs Freq Woofer and Port curves with phase 286 LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications The minimum phase curve generated by LMS produces the same relative phase for both so the SUB operation must be used and not ADD It should also be noted that no time correction is required The relative positions of the woofer and port are slightly different the dust cap is behind the port mouth but at these long wave lengths the difference is not significant After the Woofer and port curves are subtracted the result shown in the Black curve in the figure below is produced Also shown in the Bl
4. a 15 E c Phase Respons LMS 4 1 User Manual 122 Chapter 7 LMS 4 1 User Manual Processing Menu In this example the group delay was modified to include a tilt towards zero at the higher frequencies The resulting phase is shown below Using this transform proper phase functions can be generated for almost any type of desired group delay response Group Delay Response 123 Processing Menu Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction D ata Transfer Data Splice Data Realign Curve Averaging Curve Compare 124 Chapter 7 7 5 Group Delay Transform P E ES ES AIM lud R3 AB Ae ENT The Processing Group Delay Transform menu item will open a dialog which provides a method of generating group delay response data from phase response data The tool button as shown above on the Processing toolbar can also be used to activate this item The group delay transform is commonly used when you wish to view a phase response in terms of its group delay characteristics The phase response curve is specified as Right
5. Pe Pi I 29655 31F 21 3 5 2 ET HJZA IUNU SWI a 38 07 GND Port Selection LMS 4 1 User Manual Chapter 1 LMS 4 1 User Manual 15 Pin Connector LMS Card input Installation 1 4 Interface Cable Installation Locate the fifteen pin socket on the rear panel of the LMS card Connect the LMS interface cable assembly shown below to the LMS rear panel socket using the screws on the plug to secure the assembly to the socket The interface cable connects the LMS PC Card to all external audio devices by a fan out into 3 lines with XLRs The black cable with the female XLR is used to connect the LMS microphone is easy to remember that the black mic cable on the microphone plugs into the black cable of the LMS card The gray cable with the female XLR is the line input for the analyzer The line input can be used for connecting external microphone preamps to the LMS analyzer or for directly connecting any other electronic apparatus which is being tested This is a balanced line level input The remaining grey cable with the male XLR connector is the oscillator output cable This cable can be connected directly to the input of an amplifier for SPL measurements or directly to a loudspeaker when making impedance measurements This XLR line is unbalanced with pin 1 connected to the computer frame ground pin 3 conne
6. CCE DCE RE 100 NIS NONE 1 SC 8A Cn es rep PIN d o MITT Lee TOT 6 Hz Impedance of Woofer at 4 Power Levels LMS 4 1 User Manual 314 Chapter 15 LMS 4 1 User Manual Impedance Applications 15 4 Using LMS for Speaker Parameters Unlike most parameter derivation routines LMS uses a very elaborate and complex optimizer to obtain a best fit model to the entire impedance curve rather than simply deriving parameters from single points at the sides of the resonance peak The Processing Speaker Parameters method is very accurate and does not suffer from the usual problems encountered with poorly shaped resonance peaks or other resonance anomalies that may be present along the impedance curve LMS aligns the full model against the entire impedance curve Delta Mass and Delta Compliance Methods The pair of Impedance curves consists of one in free air and the other a variation curve The variation or delta curve can be produced by either adding a mass to the cone or placing the speaker on a test box of known internal volume These methods are called delta mass and delta compliance In the following example the delta mass method will be used It is very important to understand that if high quality parameters are to be produced careful attention to set up and p
7. Speaker Parameters Typical loudspeaker result for the Single Curve Electrical System method The LEAP model was used here Processing Menu LMS 4 1 User Manual gt 136 Chapter 7 LMS 4 1 User Manual Processing Menu Single Curve with Mmd This method is used when you require the complete electrical and mechanical parameters for a loudspeaker based on already knowing the diaphragm mass Mmd The resulting parameter set is the full electrical and mechanical values For this method the radiation domain must be selected as either Free Air or Infinite Baffle The radiation mass Mmr of any speaker is dependent on the air load and this is different for these two domains For speakers mounted and measured on IEC baffles or other large surfaces the Infinite Baffle selection is appropriate If the speaker is held in free air or clamped to an open frame structure the Free Air selection should be chosen The parameters for Revc Sd and Md must also be entered Revc is the DC voice coil resistance as typically measured with a DMM The Sd value is the piston area of the speaker You can click the Ellipse button for another dialog which will compute the Sd value for you based on diameter or radius The Md field is where you enter the diaphragm mass Mmd for the speaker In the Model Simulation panel choose a curve entry to place the model simulation curve After c
8. 69 5 3 NOTES Gc Comment 75 Chapter 6 Analyzer Menu 77 i I AA 79 6 2 SWEEP Stall OlOD da an ed ard neue 89 623 OSCOONMOTE 90 64 ALG MCLG MT 91 6 5 Microphone Setup 94 6 6 PAG Interact ini ar M un 95 6 7 Macro RUT Lien an A A RID xig RES 99 6 9 GalibEdUOT ins 100 LMS 4 1 User Manual Contents Contents Chapter 7 Processing Menu 103 7 1 Unary Math Operations 2 2 2 105 7 2 Binary Math Operations 2 115 7 3 Minimum Phase Transform 117 7 4 Delay Phase Transform 22259 hte 121 7 5 Group Delay Transform 2 124 7 6 Inverse Fast Fourier Transform 126 7 7 Fast Fourier Transform bees 130 7 8 Speaker Parameters 131 7 9 Tall CUIU 145 1 10 Data MANSION Mines 147 LAT Data SOC Lr 149 Zoe 151 7 13 Cuve Averaging Paese 153 1 14 Curv COMDATE 157 Chapter 8 Utilities Menu 161 8 1 Import Curve Da
9. LMS 4 1 User Manual When writing the Library Curve data you may or may not have edit nodes which cover the entire frequency range If the end nodes do not reach the ends of the frequency range the final end values will be extrapolated in the Library Curve The sample here shows a node curve that does not reach the low frequency limit and the resulting Library Curve after be ing written The end node value is used to complete the curve to the end frequency After the Library Curve is written it is also enabled for display If you have enabled the Show Curves 1n the menu it will immediately appear in the Curve Editor graph 191 Utilities Menu Chapter 8 192 LMS 4 1 User Manual Chapter 8 Utilities Menu 8 7 Macro Editor EDT Curve Data File Export Curve Data File E Dm GR Export Graphics to File Export Graphics to Clipboard The Utilities Macro Editor menu item will open a special text file editor for creating and editing macro script pro Macro Editor grams The tool button as shown above on the Utilities MDF Editor toolbar can also be used to activate this item Curve Capture Curve E ditar The Macro Editor is ideal for creating macro programs It has many of the standard features of any regular text editor but also provides syntax highlighting for the LMS macro commands and syntax Macros can also be printed with syntax highlighting Multi level undo redo is
10. T 000 shows the type of data con Vas cul SPLo CES a 354 tained in each curve Any curve which is currently Model Simulation Estimate Optimize Simulate Reference Curve 25 SpkrMnodel woofer 1 Revc Freg Imp Phase being displayed on the Estimate Optimize Simulate Delta Curve mid 29G Freg Imp Phase 4 graph 15 denoted by Red LMS 4 1 User Manual vertical lines between the Cancel Help zones of each curve entry 131 Processing Menu 132 Chapter 7 Single Curve Elec Motor This method is used when no mechanical resonance hump is present This means that only resistance and inductance are depicted in the impedance curve The two most common examples of this are a blocked electrodynamic speaker or a ribbon speaker There are only two Input Parameters that need be specified the curve containing the reference impedance data and the Revc value Revc is the DC voice coil resistance as typically measured with a DMM In the Model Simulation panel choose a curve entry to place in the model simulation curve After clicking the Estimate Optimize Simulate button an estimate of the parameters is derived from the input data and then optimized for best fit The simulation curve is then placed into the specified library curve entry The following two pages show an example of a typical parameter generated for both the Standard and LEAP models In both case
11. E xm Vas cuFt SPLo dB 00 24 6 445 89 176 Operatio Estimate Optimize Simulate Estimate Optimize Simulate Model Simulation Reference Curve 21 SpkiModel 12 1 62 Freq mp Phase Delta Curve 22 DeltaModel Hw12a162 Freq mp Phase 1 10 Hz 20 50 142 100 200 500 1K 2K 5K 10K LMS 4 1 User Manual Chapter 7 LMS 4 1 User Manual Processing Menu Data Transfer The derived parameters are also listed in a memo area on the second tab in the center of the dialog This is an ASCII text listing format The list can be edited manually in the memo region and then copied to the clipboard printed or saved to a disk file When the parameters are derived the complete parameter set is also automatically placed into the nfo fields of the simulation curves Speaker Parameters 11 Ha a 1 62 Freq mp Phase 12 2 0697 Freq mp Phase 1m 200 Loudspeaker Measurement System LMS TH 4 0 0 231 Jul ol 2z000 Clopyright 1393 2000 by Linearx Systems Inc ElectroMech Speaker Parameters Jul z 000 Sun 4 22 am Library Carlza lib Reference Curve Hillz a 1 62 21 SpkModel HW1241 62 Freq mp Phase 22 DeltaModel Hw12a1 62 Freq mp Phase
12. Hz Mic Correction Curve Loaded into the Library Ratio vs Fre 20K 10K 5K 2K 1K 500 100 50 20 Hz EQ Curve to Aad to Mic Curve LMS 4 1 User Manual 338 Chapter 16 LMS 4 1 User Manual Misc Applications 16 6 Quality Control Pass Fail Testing Speed is usually the primary concern in a production environment when testing loudspeakers The final test before packaging is generally some type of SPL test which can determine if the drivers fall within a certain SPL range and whether or not the driver polarities are correct LMS has a special routine which can perform SPL Pass Fail testing just for this purpose titled Curve Compare The physical setup for performing Pass Fail SPL measurements will depend on the requirements of each individual manufacturing situation Typically the test is performed on the production floor where a high ambient noise level is present Since it is also frequently impractical to have an acoustically isolated environment to perform the testing many manufacturers fabricate some type of semi quiet area for the testing This can consist of partitioning with substantial amounts of acoustic damping material attached plus floor and ceiling damping material placed in the vicinity of the measurement The microphone is often placed close to the test speaker within 10 12 A
13. ICM DOS EN EN 6005 EEE CZ HT DELL LEZ Be 011 CN SEDES E NES ERE D OI PERE AOE OE LEE M ON Curve 8 C13 Partioned Inductance vs Fre 5 5 2 RCE O O O RACE _ LE n Ls pet Ee L RARR I EE _ LA Wl ICI NT Ca Li LL CN RCE BON CS CO E AC OOo EN BE PROFIT Or SR OOD _ _ m 321 LMS 4 1 User Manual Misc Applications Chapter 16 322 LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications 16 1 Passive Network Transfer Functions LMS can be used to find out exactly what a passive network is doing under real speaker load conditions Many times this is helpful to see if the network 15 really performing as intended The test setup is shown below for the enclosure system depicting the essential areas for testing The first step is to take a sweep of the voltage going into th
14. Parameter Di Show All Hide All Delete Delete 472 5 deg i 165 deg H 457 5 deg 42 150 deg 43 442 5 deg 44 135 deg 45 427 5 deg 46 PolarCony F 4 PolarCony 48 PolarCony F 43 PolarCony F 50 PolarCony F 204 2 Q000K 10 0000K 20 0000K 40 0000 o Horz Data Range 10 2 40 0KHz is 10 2 40 0KHz 10 2 40 0KHz 10 2 40 0KHz 10 2 40 0KHz 10 2 40 0KHz 10 2 40 0KHz Tes 180 0 180 0D eg Tes 180 0 180 0D eg Tes 180 0 180 0D eg Tes 180 0 180 0D eg Tes 180 0 180 0D eg Left Ve SPL SPL SPL SPL SPL SPL SPL SPL SPL SPL SPL SPL oes Chapter 8 Cure Frequency Deg Q DI 200K 360 10 00 500K 360 10 00 10 00K 270 13 13 20 00K 142 25 4 1 40 00K 125 29 46 0 Deg Library Curves EP GEN 21 Input Deg 180 0000 180 deg 10 2 40 0KHz SPL Phase 5 Input Deg 180 0000 180 deg 10 2 40 0KHz SPL Phase 33 Input Deg 172 5000 172 5 deg 10 2 40 0KHz SPL Phase 40 Input Deg 165 0000 165 deg 10 2 40 0KHz SPL Phase 41 Input Deg 157 5000 157 5 deg 10 2 40 0KHz SPL Phase 42 Input Deg 150 0000 150 deg 10 2 40 0KHz SPL Phase 43 Input Deg 142 5000 142 5 deg 10 2 40 0KHz SPL Phase 44 Input Deg 135 0000 135 deg 10 2 40 0KHz SPL Phase 45 Input Deg 127 5000 127 5 deg 10 2 40 0KHz SPL Phase 46 Output Freq 2 0000K PolarConv F 2 0000K 180 0 180 0De
15. 19 2 4 Graph Hot Spots amp Popup Menus _ 20 2 5 Quick View Window 7 21 2 6 Graph Scrolling 22 2 7 Numeric Entry amp Formats 23 2 8 Color Select Dialogi 25 2 9 Font Select Dialog 28 2 10 Analyzer Block DIagE atm siemens 30 Chapter 3 Getting Started 3 1 3 1 The Analyzer Control Panel 33 3 2 Using Quickset FIGS aos tune 34 3 3 An SPL Measurement 35 3 4 An Impedance Measurement 41 3 5 The Scale System 44 LMS 4 1 User Manual Contents Contents Contents Chapter 4 File Menu 45 MESI TEUER 47 2 2 C 48 Ac or Ic 49 E DA 50 HD 51 i i 52 4 7 Load QuickSet File iii iii 53 48 Save QuickSet File iii 54 Z9 acta AES UI 55 is et LU esses 58 AA We Prell nees 60 Liu fU t i 64 Chapter 5 Graph Menu 65 5b T P aramelefS 2 sede A 67 DA Curve LID a eai
16. DATACURVE DBLIN gt DEC a DELTA END ERBEEP EXITTODOS EXPORT J EXPORTCN EXPORTFEN EXPORTVN EXTCAL GRPHCURVE GRPHSCRN IFCRKEYGOTO IFSBKEYGOTO IF GOTO 000 INC uos INPUT INTCAL LEVEL LMSINIT LOADLIB LOADQS Comment ADD curves A B Command Line Clear Command Line Message Compare a curve Copy a curve to another entry Change Curve vertical Units Set the sweep data curve entry Converts dB curve units to Linear now obsolete Decrement a variable value DELTA curves A B Same as SUB DIV curves A B Same as RATIO End of Macro Error Beep Sound Exit the Macro Export ASCII Data File Export ASCII Data File use CurveName Export ASCII Data File prompt fro FileName Export ASCII Data File use variable for FileName Run Internal Calibration Go to Line Number Set the curve entries to graph RollUp MacroRun Dialog If CR keystroke occurs then goto line If SB keystroke occurs then goto line If variable value then goto line Increment a variable value Input an integer to variable Run Internal Calibration Levels acurve Same as SMOOTH Initialize LMS Hardware factory use Load Curve Library Load QuickSet File 273 Macro Programs 274 Chapter 13 LOADMIC 14 Load new MDF file for Mic input MAKESPLZ Make a combination SPL and Z curve entry ME
17. Utilities Menu 8 8 MDF Editor Import Curve Data File Export Curve Data File Export Graphics to File Export Graphics to Clipboard Curve Capture Curve Editor Macro Editor MOF Editor Utilities F1 E E BGEMESG The Utilities MDF Editor menu item will open a dialog for creating or editing MDF files The tool button as shown above on the Utilities toolbar can also be used to activate this item E An MDF Microphone Data Format file defines the response and sensitivity of a microphone Your included M31 mic already comes with its own MDF file However if you are using an external microphone you will probably wish to use this utility to create an appropriate MDF file for your mic AnMDF file consists of two basic components a group of text fields with parameter information and a normalized curve giving the response of the mic Save to Cure Freq Ration Phase The parameter definitions provide general information about the mic and define its basic sensitivity The response curve is generally normalized to OdB at 1kHz and gives the mic s frequency response There is no restriction on the number of points in the curve or the frequency range However the maximum number of data points supported here is 4096 and the frequency range should cover the intended use range For LMS a log resolution should be used Data for the editor can be loaded from an existing MDF file Library Curves the int
18. In order to be in the near field region the microphone must be placed very close to the piston source The maximum distance permissible is dependent on the frequency range being measured At low frequencies the near field distance will be much greater than at high frequencies For measuring woofers placing the microphone within 0 25 inch from the cone will produce excellent near field curves If there is a port the mic should be placed in the baffle board plane of the port mouth For midrange drivers placing the microphone as close as possible without touching the cone is necessary Midrange near field measurements can be very tricky If good high frequency results are required the mic must be almost touching the cone For tweeters near field measurements are impractical The problem for multi way enclosures is that you cannot be in a near field condition for all the drivers simultaneously due to their spread out locations on the baffle board However for single driver measurements near field methods can be useful This is especially true for measuring low frequency response from woofers The near field method eliminates the need for any large open area around the speaker 283 SPL Applications 284 Chapter 14 However if separate measurements are taken for different ranges of an enclosure LMS can be used to sum these results together In this manner a full range frequency response curve can be produced A good choice would be t
19. LMS Sample lib File Graph Analyzer Processing Utilities Scale View ToolBars Help 18 SSHAGRAS 1 184 E E T FAR amp 4 a gt asl ES SPL vs Fre 95 150 p SAPE INTR LA 7 LMS Sample lib le x 85 E Graph Analyzer Processing Utilities Scale View ToolBars Help Quick View x 80 E SPL vs Fre A 5I UN RU 45 40 10 Hz 20 50 10 P25 at 1M 132 abs _Rel P25 at 1M LMS 4 1 21 User Manual General Features 22 Horizontal Scroll Bar 2 6 Graph Scrolling amp Panning Chapter 2 There are two scroll bars on the graph window one for vertical scrolling and one for horizontal scrolling Either or both may or may not be present depending on the zoom level of the graph window You can also drag or pan the graph window directly by use of the mouse First press and hold the SHFT key and then while holding the left mouse button drag the artwork The normal mouse pointer will be changed to a hand symbol LMS Sample lib File Graph Analyzer Processing Utilities Scale View ToolBars Help dBSPL 100 95 12258 E EUIS SPL vs Fre MELLA TT 5 55 90 85 75 120 150 4 132 Abs Rel 1 P25 a
20. T HSY Sat 2 56 5 pce EN Val 72 63 1 ooo Original Color The Color Select dialog provides many powerful and convenient features for color selection and editing Three different color models are supported as well as live mouse editing on a color wheel Colors can be picked from presets and new user defined colors can be saved as well The dialog contains many small color pads which have the dual function of display and selection Clicking a color pad loads the color as the current selection If the current color matches one of the pads than the pad will be highlighted LMS 4 1 25 User Manual General Features 26 Chapter 2 Standard Colors These are the 20 standard Windows colors Some of the black colors are actually masking colors but the remainder are generally the primary VGA 16 set If your video mode is 16 or 256 color then choosing one of these colors will provide for solid color Other special colors will require dithering which may be undesirable Clicking on one of the pads will select the color Extended Colors There are 30 additional colors provided here for quick selection Your video mode will need to have more than 256 colors for solid display or they will be dithered Clicking on one of the color pads will select the color Custom Colors There are 20 additional locations provided here for user custom colors When the Add Custom button 15 clicked the current color wil
21. 30 response curves mea sured across 10Hz B 40kHz 50 curves were then 420 normalized to the on axis 40 Hz 20 LMS 4 1 User Manual 50 150 0 Degree curve This s lished by di 100 200 500 1K 2K 5K 10K 20K 40K was accomp isne 1 viding all curves by the 0 Degree curve In this way the response at each location around the transducer is relative to the on axis response It was desired to produce 5 polar curves for the higher frequencies of 2kHz 5kHz 10kHz 20kHz and 40kHz Since there are 48 input curves and 5 output curves are required it was decided that a couple of the input curves would be deleted Since the response near the 0 Degree on axis location 15 relatively smooth the deleted curves were chosen to alternatively skip every other curve near 0 Deg Thus the resolution near the 30 Degree on axis region was 15 Degrees 201 Utilities Menu Polar Convertor x Library Curve Deg or Freq Right Polar Convertor Library Curve Deg or Freq Right 202 ce e cn ro ere Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg 30 0000 52 5000 5 0000 67 5000 0 0000 52 5000 45 0000 37 5000 30 0000 37 5000 15 0000 105 0000 0 0000 112 5000 Standard 360 Deg Inpu
22. Chapter 14 LMS 4 1 User Manual SPL Applications Most FFT type analyzers generate data that goes far below this critical gating frequency The data near and below this frequency is meaningless and must be ignored LMS helps in this regard by not even attempting to measure below the critical gate frequency The response below this frequency is set to a flat line For example a 1015 meter ON time will produce excellent results down to 200Hz with final data cut off at 100Hz Below 100Hz the data is eliminated Toaccurately measure an enclosure using a gate method itis necessary to maximize the distance to the closest boundary This is always desirable to enable measure ments down to the lowest possible frequency The ground plane method can be used for this purpose Typically the nearest wall or ceiling would produce your closest boundary For gated measurements a pole method can also be used This is shown in the figure below Here a small platform on top of a pole is used to hold the cabinet off the floor or ground This method produces an anechoic type result when used with gating 1 Meter MIC 17 2 Meters 289 SPL Applications 290 Chapter 14 Gating Example The primary limitation on the low frequency limit of gated SPL measurements is the distance to the nearest boundary The meter gate ON time must be short enough that it does not pick up the first reflection from a nearby boundary It should be o
23. Curve Name This panel displays the name of the library curve that the cursor is tracking If the cursor is not on a curve then N A will appear Using the following spin buttons you can move the cursor to a different curve The cursor will only track curves which are visible Curve Select Spin Button This panel contains a spin button for changing which library curve the cursor is tracking When stepped it will skip any curve numbers which are not currently being displayed You can also change the curve by using the keyboard arrow keys Up Dn Curve Line Sample This panel contains a sample of the curve line as it is drawn on the graph This is the library curve that the cursor is tracking When curves are drawn in different colors it is easy to indentify which curve the cursor is currently tracking by this sample line segment 235 Toolbars Menu Chapter 11 11428 Hz 408768mdBm Lek Fight MM Horizontal Data This panel displays current horizontal value of the cursor at the present position Usually this is frequency Vertical Data This panel displays current vertical value of the cursor at the present position Usually could be voltage dB SPL Impedance etc Left Right Vertical Data These two buttons control which portion of the library curve to track either the Left or Right vertical data Left data is generally magnitude and Right data is typically phase Progress Meter The next panel contains a progress meter tha
24. EE 22922522 Ratios of Car Response vs Ground Plane LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications With the windows open the response at the low end below 60Hz increases by about 5dB relative to when the windows are closed We can produce another ratio by dividing these two curves to see what the relative difference is between the windows being closed or open This is shown below It is interesting to note that above 100Hz there is very little difference between the windows being closed or open Below 100Hz there is generally a higher level with the windows open The response characteristics for most cars will always be slightly different In the case of vans or even household rooms the response will again be different By using the utility tools in LMS the relative differences between any given environ ment and a controlled measurement environment can be quickly accurately and easily evaluated dBSPL 5 Es eene eee EDS ERE ELEZI EEE Ae EEE AAAA LASA MAAA NH 2 D D EBEN Ratio of Windows Open vs Closed 295 SPL Applications Chapter 14 296 LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications 14 8 Acoustical Summations With LMS itis possible to sum together the respons
25. Location Option Center of Page f Corner of Page Scaling Option Scale Factor 2 50 00 55 File Menu 56 Chapter 4 Color Options This panel provides two options which control how the graphics are printed If the Color Gray option is selected and you are printing to a black amp white device the colors in the artwork will be dithered to produce gray levels When the Black amp White selection is used all colors in the artwork graphics will be printed as black regardless of the printer This is a very useful feature when printing to a dot matrix device Gray halftones of low resolution on small lines or fonts may often result in unreadable graphics Printing all colors as black will eliminate this problem and produce better looking plots on low resolution devices For printing on laser or ink jet printers where higher resolution is available it may be a matter of choice as to the representation of color Gray lines of varying density may help to produce more identity between multiple lines on the graphs With the low cost availability of color ink jet printers today printing in color will usually be the most popular choice Location Options This panel provides two options which control where the graphics are printed on the page If you are printing in full size neither option will be much different since the artwork will mostly fill the page regardless However if the graph is printed at reduce size the
26. BL 5 38 TM Ome 7 383 0 366 0 349 No 0 5204 SPLa 28 51 0R Vas 6 445cuFt Cms 1 172mM N Erm 6 553m0hm Erm 0 750 Mms 46 704g Mmd243 038mKg Kxm 32 8383mOhm Exm 0 629 P Test ta Graph T Copp lnia Test ta Right Graph Wates 143 Processing Menu Chapter 7 144 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Fourier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Curve Averaging Curve Compare Tail Correction Parameter Library Curve 8 P25 1M Tails Freq Hi Hz 0000K 15 0000 Freq Lo Hz ee LMS 4 1 User Manual Slope Hi dB Oct Slope Lo dB Oct Processing Menu 7 9 Tail Correction P E E ES AMHR DAE The Processing Tail Correction menu item will open a dialog that provides a means to fix the low and high ends of a curve so that the asymptotic slopes are precisely defined The tool button as shown above on the Processing toolbar can also be used to activate this item Many of the process operations require data at frequencies beyond the range over which the curve was originally measured The Minimum Phase Transform 15 particularly sensitive and requires correct magnitude slopes at both the low and high ends of the frequenc
27. C Relative Absolut Limit Curve 15 Max Limit Freq SPL Min Limit Curve 1 Min Limit Freq SPL Phase Relativ Tolerance dE 1 0000 t Reference Euwe 4 Relative Reference Curve 1 180 deg Freq SPL Phase Cancel Help Test Curve Exceeded Min Limit Curve F 10 1514 Abs Compare FAILED 550 0000 LMS 4 1 157 User Manual Processing Menu Chapter 7 Anexample of an Absolute testis shown below The test curve is shown in Blue and the max min limit curves are shown in Red The limit curves were produced using the Curve Editor and only required 10 data points Careful inspection of the test curve will show that it fails the min limit at about 7 3kHz However if the frequency limits are set to say 10Hz and 5kHz the test passes This is an example of how the frequency limits are applied Curve Compare x Metho Absolute Test Parameter Lo Freg Hz 10 0000 Hi Freg Hz 5 0000 14 5 Freq SPL Phase C Relative Absolut Limit Curve 15 Max Limit Freq SPL Phase Min Limit Curve 16 Min Limit Freq SPL Phase Helativ Tolerance dE 1 0000 t Reterencelunve 4 Relative Reference Curve 1 180 deg SPL Phase F T SPL vs Freg 10 10 Hz 20 50 100 200 5
28. Processing Menu 7 13 Curve Averaging P E ES RAM MG A A Sea The Processing Curve Averaging menu item will open a dialog which performs averaging of multiple curves into a single curve The tool button as shown above on the Processing toolbar can also be used to activate this item It is sometimes desirable to average multiple measurements to come up with a single representative curve Curve Averaging can mathematically average up to 50 curves and store the data in a separate library entry or on top of one of the data curves being averaged A common use for this utility is generating a true power response curve from multiple curves taken at different off axis angles around a transducer Other uses include averaging of multiple curves to determine the mean and then worst case max min variations from that average response Four different types of mathematical averaging are provided The Curve Param eters panel shows a data grid with the 50 library curves Each curve entry can be enabled or disabled for averaging A weighting value can also be specified for each curve Below the grid is another selection box for the resulting average curve Two additional buttons are provided for quickly enabling disabling all curves The Result Curve list box provides se Metho lection of the library curve for the result Scalar Ave Curve Parameter 1 000 1 000 1 000 1 000 1 000 1 000 1 000 1 000 310 LS T ST
29. or Win2000 50MB free Hard Drive space E 32MB RAM Memory Pentium 500 or better Video 1024 x 768 Res 64K or 16M Colors Adobe Fonts with Adobe Type Manager Installation Chapter 1 1 2 Software Installation This software requires a full Win32 operating system such as Win95 Win98 WinNT4 or Win2000 It cannot be installed under Win32 Win3 1 This software requires version 4 72 or higher of the Windows common control library COMCTL32 DLL This will be checked during installation and your system will be upgraded if necessary Note IMPORTANT If you are using NT your NT user account must have Administrator rights This is necessary to install the kernel driver Installation Instructions Place the distribution CD into your CD ROM drive If the CD does not AutoRun locate and run the Setup Exe file Follow the instructions on the screen Select an electronic or manual Registration method The registration will prompt you for the LMS card Serial Number which can be found on the LMS PCB or the product box Microphone Data Format MDF File During the installation you will be asked if you have an MDF floppy disk This disk contains the calibration data for your M31 microphone When prompted insert the floppy in Drive A and the file will be copied to the application directory LMS MDF When you later start the application software for the first time you will need to setup load this MDF
30. radiation domain 139 Range 211 Raster 167 raster formats 169 Raster Images 1068 RATIO 270 RCA 35 readouts 40 real 353 Real cos 114 real number format 24 REALIMAG 267 rectangular and circular plots 44 rectangular or circular plots 208 Redraw 225 reflecting surfaces 279 reflection path 83 Reflection Spikes 291 Relative 157 Relative Cursor Mode 62 Relative Flatness 1060 Relative Reference 159 RELCOMPARE 268 Reopen 49 resistance 91 resolution 56 resolution of acurve 151 Reve 132 reverb time measurements 86 Index Revert 52 RGB 26 ribbon speaker 132 Right Lighter 71 Right vertical 147 RLC bridge 85 RLC Meter 91 Roll Up Roll Down 79 RollUp RollDown 33 RT60 85 Rub amp Buzz ruler 184 Running Macro Programs 254 Running the Speaker Parameters 317 023 927 S Same Line Type 71 Save As 51 Save QuickSet File 54 SAVELIB 268 saving library files 51 Scalar AVE 154 Scalar RMS 154 SCALE 268 Scale Auto 213 Scale Down 217 Scale Parameters 207 Scale Up 215 Scale System 44 Scan Direction 177 scanner 175 scientific 353 scientific format 24 scripts 253 Scrolling amp Panning 22 Sd 137 sensitivity 195 Serial Number 4 363 Index 364 serial number 249 serial port 95 SETSCP 269 SETVAR 269 shortcut link 254 Show 70 229 SI multipliers 23 simulations 131 sine wave 80 Skip First Column 164 SMOOTH 269 Smooth Curve 105 110 snap 181 Software Installat
31. 100 PULSE REALIMAG OrgCurveNum RealCurveNum ImagCurveNum separate the Real amp Imag components into other curves This command takes the cos and sin of the OrgCurveNum and writes two new curves RealCurveNum and ImagCurveNum Example 100 REALIMAG 1 11 12 267 Macro Programs 268 Chapter 13 RELCOMPARE Testnum dB LoFreq HiFreq Compares a curve with dB rel tol between Lo and Hi Freq Range The RELCOMPARE keyword is used to compare a curve between a relative flatness tolerance and gives a PASS FAIL response The range for comparison can be limited to less than the actual curve frequency range The first parameter is the entry number to test and the second parameter is a positive dB value The LoFreq and HiFreq parameters are real numbers which specify the actual range to be tested This operation finds the average base line level of the test curve and then checks to see if any of the points on the curve are above or below the average by the dB tolerance value This is useful to check curves for relative flatness If the test curve differs from the average by more than the dB value a FAIL message will be given The following example tests curve 11 for relative flatness within 2 5dB from 35Hz to 15kHz Example 100 RELCOMPARE 11 2 5 35 15E3 B SAVELIB Saves the current curve library in memory to disk The SAVELIB keyword is used to save the curve library Example 100 SAVELIB SCALE entrynumber dB S
32. 180 0000 Reference Point Data Lower rs Fisel Coord Y Harz 97 647 10 0000 Left Ohm Right Vert Deg 2 0000 E 80 0000 Scan Directio Bottom Bottom to Top Color Preview Clear D 5 HER Library Curv D Program Files Borland Delphid ProjectssSLMSSIMPORTStest Load File He Graph Image The large region displays the raster image currently loaded The display 15 always a 1 1 pixel ratio and has scroll bars on both axis The Load File button will open a dialog to select the BMP file you wish to load The path of the currently loaded file is shown adjacent to the button Cursor Parameter Selection There are four parameters which must be defined with the image Lower Left coordinate Upper Right coordinate the Left Curve Color and the Right Curve Color The color panel nextto the Curve buttons displays the currently selected color for the curves Two curves Left Right will be captured from the image To set a parameter click one of the four toggle buttons and move the mouse cursor over the image A different cursor will appear which denotes the parameter to be set Click the eft mouse button and the parameter will be defined at that cursor location The button will then reset If you wish to cancel a parameter click the button again and it will reset LMS 4 1 User Manual Chapter 8 LMS 4 1 User Man
33. A large data grid table displays the 50 library curve entries The points column informs you whether each entry actually contains data oris empty The names of each entry are editable by the user and in many cases will be initially created by processing or import operations Each curve can be individually enabled for display on the graph and has definable line color width and style A library curve is actually a pair of curves with a left side vertical data type and a right side vertical data type In most cases these represent magnitude and phase respectively although any data can be transferred to either vertical side The Data Curve edit box allows you to select which of the curves will be used for the next sweep measurement data This can also be chosen by double clicking on any curve entry You can also use the shortcut key CTRL D Single or multiple curves can be selected by holding down the Shift or Ctrl keys while selecting another curve with the mouse All ofthe curves can be selected at once by using CTRL A The Show All and Hide All buttons will enable or disable all of the curves for display on the graph Itis often useful to use the Hide All button to shut off all curves You can also toggle selected curves for display by using CTRL G 70 LMS 4 1 User Manual Chapter 5 LMS 4 1 User Manual Graph Menu The Cut button will first copy the selected curves to the Windows s Clipboard and then delete them from the libr
34. As frequency is decreased the time period for a cycle increases The following table illustrates some example values Freq Period 10Hz 100mS 100Hz 10mS 1kHz ImS 10kHz 0 1115 The period is the amount of time required for a sine wave to make one cycle Because of the inverse relationship between period and frequency the lower the frequency the longer the time required to read or capture a signal For example a sine wave at 10Hz will take 100mS to make a single revolution through its cycle If the meter window ON time is only 10mS the waveform will only have passed through 10 of its full cycle There is no way that the meter will even see the full cycle to measure its amplitude If the frequency of the waveform was then there would be 10 cycles passing through the window which would make level measurement very easy LMS uses an instantaneous detector for gated sweep modes that can capture the signal level in a single cycle or even less However this assumes that when the meter window opens the signal has arrived perfectly on time to be read In reality this 1s quite difficult to achieve given the delay through the air and transducer response These quantities are difficult to measure or determine perfectly As arule of thumb the low frequency limit will be approximately equal to the reciprocal of the meter window ON time In many cases the response will start to degenerate at twice this value LMS 4 1 User Manual
35. C cable impedance 307 Calibration 100 Capacitance 85 capacitance 91 Capacitor Curve Examples Capture Dialog 178 Car Interiors 292 Clamping of Speaker Clipboard 71 173 Clipboard Viewer Cms 137 CMY 26 132 345 316 174 357 Index 358 Color Format 168 Color Match 178 Color Select Dialog 25 Color Space 27 COM port 3 COMCTL32 DLL 4 COMLCLR 259 COMLMSG 260 communications link 95 COMPARE 260 Compression 168 consecutive frequencies 191 constant current 307 control bar 231 Control Bar Texture 62 Control Bars 17 COPYCURVE 260 Creating Macro Programs 255 crosshair 189 cubic 151 current library 51 cursor 18 Cursor Style 61 Curve Averaging 153 Curve Capture 175 Curve Compare 157 Curve Data Manually 331 Curve Editor 181 Curve Editor Screen 182 Curve Info Dialog 73 Curve Library 36 69 Curve Line Sample 235 Curve Select Spin Button 235 Custom Adjustments 341 Custom Colors 26 D Data Curve 89 data curve 37 Data Realign 151 data realignment 152 Data Splice 149 Data Transfer 147 data units 37 DATACURVE 260 dB per Division 211 dB Reference 211 DBLIN 261 Debugging and Error Reporting 257 DEC 261 default extension 51 Delay Offset 108 Delay Phase Transform 121 DELTA 261 Delta Compliance 141 Delta Mass 139 Delta Mass and Delta Compliance Meth ods 315 display scale factor 223 distill vector curve data 175 dithered 56 DIV 261 DLLs 247 DMM 132 DPI 169 Drag
36. Funcion Deg or Frea Nome Horane let entered as either 180 or O to 360 but will be 1 Input Deg 170 0000 SPL Phase 2 InputDeg 1600000 SPL Phase automatically converted to the 180 range 3 Input Deg 150 0000 SPL Phase 4 Input Deg 140 0000 SPL Phase 5 Input D 130 0000 SPL Ph 11200000 SPL Phase The Output Freq selection is chosen for output 7 Input Deg 110 0000 SPL Phase 8 inpuDeg 11000000 x Ics curves which will contain a polar response at a 9 Input Deg 90 0000 SPL Phase ec 10 InputDeg 80 0000 SPL Phase specified frequency 11 Input Deg 70 0000 SPL Phase 12 Input Deg 60 0000 SPL Phase 13 Input Deg 50 0000 SPL Phase 14 Input Deg 40 0000 SPL Phase All Off _Standard 360 Standard 180 This button will reset the Function column to Not Cancel He Used and set the Deg or Freg values to zero Standard 360 This button will produce a standard setup for 36 Library Curves input curves covering 10 Deg radial resolution FE SESTERCE C SNR LSU EIL TER ES across the 180 range There will be 14 output Input Deg 85 0000 SPL Phase eea curves in 1 2 octave intervals from 40kHz and nput Deg 75 0000 SPL Phase 4 Input Deg 70 0000 SPL Phase 5 Input Deg 65 0000 SPL Phase lower B Input Deg 60 0000 SPL Phase 7 Input Deg 55 0000 SPL Phase 8 Input Deg 50 0000 SPL Phase Input Deg 45 0000 SPL Phase Standard 180 pps This
37. In some cases you may wish to copy the curve into another entry justin case you wish to reuse the original data later Several different types of operations are provided Magnitude Offset Phase Offset Delay Offset Exponentiation Smooth Curve Frequency Translation Mul j Div j Real cos Imag sin The dialog use is straightforward Simply select the library curve to process the operation and enter the desired numeric value for the operation Only the numeric field for the selected operation will be enabled with all other fields disabled The following examples demonstrate some various applications of each operation Unary Math Operations x Library Erde The Data Curve list box provides 18 C13 Packed Freg Imp Phase selection of the library curve for the operation This speciallistbox shows 1 0000 d the type of data contained in each Phase Offset Zero 20 0000 D curve Any curve which is currently Dely se 0 0000 Hs being displayed on the graph is de Esponentiati 1 0000 P noted by Red vertical lines between Smooth Curve 250 0000 Oct the zones of each curve entry Frequency Translation 1 0000 Ratio Multiple C Divide by ju Real cos Imag sin oes 105 Processing Menu 106 100 95 90 85 5 Chapter 7 Magnitude Offset This operation simply adds the numeric dB value to the magnit
38. MIC Curve Entry Number 15 Data Woofer True DataPoints 552 Ohms Frequency Hz 10 1514 10 1514 10 3051 Horizontal Left Vertical and Right Vertical Data Understanding the use of these three panels is key to the proper import of external data Each panel corresponds to the data in one of the file columns The general format is assumed to contain three data columns Typically this may be frequency magnitude and phase Ifyou have less than three columns such as frequency and magnitude use the phase selection for the third column anyway This will automatically substitute zeros for the missing column The type of data and units prefix is critically important to define what it is you are importing Always verify that the Units field displays the exact units that the data column contains For example a voltage measurement could have a magnitude column with data in units of Volts dBV or dBm The program treats each of these differently Linear Log would be used for Volts and the dB selection would be required for dB V or dBm For dB units the dB Ref value then defines whether it is dBV 1 000V or dBm 0 775 If your file contains acomment line listing the data column units then these can be read immediately in the viewer as shown above If your file contains an index column of numbers as the first column then use the Skip First Column option to ignore this column LMS 4 1 User Manual Chapter 8 U
39. Note Verify that the Voltage Selector switch is in the correct position for your local power 110VAC or 220VAC before connecting the AC power cord The next step is to connect the serial port cable to your computer You will need a free serial port Your mouse may already be using a port such as COMI so you will need to use one of the other three serial COM ports 2 3 or 4 Depending on whether your computer s connector is a DB25 pin male or a DB9 pin male you may or may not need to use an adapter on the line PAC Interface E Start Link System Statu Link Status Inactive OFF Baud Rate 0 LMSI Pat 0 PACCPURev 12 Bus Voltage BB 1 2v Bus Voltage BB 5 Bus Voltage OO Fy Bus Voltage Battery Voltage BB External Voltage BB Automatic Link Power Source 14400 19200 28800 C 38400 v 57600 Batten Status Turn on the power to the PAC unit either battery or external and after a few seconds the unit will beep to let you know it is ready for operation Start the LMS software and then go to this dialog Charge Amps LMS 4 1 95 User Manual Analyzer Menu 96 Chapter 6 Note After you have setup and activated the link for the first time you MUST run the Calibration routine to establish the correct operating parameters for the LMS even if you have previously done this already when the analyzer was mounted in your computer
40. RER p UA 22 i 138 Chapter 7 LMS 4 1 User Manual Processing Menu Double Curve Delta Mass This method is based on the use of two curves one reference curve and another delta curve where a known mass has been attached to the cone Complete electrical and mechanical parameters are derived for the loudspeaker based on the change in Fo due to the delta mass The resulting parameter set is the full electrical and mechanical values For this method the radiation domain must be selected as either Free Air or Infinite Baffle The radiation mass Mmr of any speaker is dependent on the air load and this is different for these two domains For speakers mounted and measured on IEC baffles or other large surfaces the Infinite Baffle selection is appropriate If the speaker is held in free air or clamped to an open frame structure the Free Air selection should be chosen The parameters for Revc Sd and Md must also be entered Revc is the DC voice coil resistance as typically measured with a DMM The Sd value is the piston area of the speaker You can click the Ellipse button for another dialog which will compute the Sd value for you based on diameter or radius The Md field is where you enter the delta mass added to the speaker You must also select the two library curves locations for the reference and delta impedance curves In the Model Simulation panel choose
41. User Manual Chapter 5 LMS 4 1 User Manual Graph Menu 5 2 Curve Library Graph Parameters pave L Curve Library Notes amp Comments The Graph Curve Library menu item will open a dialog which controls the library of curves used in the program The tool button as shown above can also be used to activate this item as well as the shortcut key F6 This is a dialog which is frequently used Library Curves are arbitrary data that can represent measurements obtained by the analyzer generated by processing functions or externally imported into the program There is a maximum of 50 library curves Library curves can contain a wide variety of different types of data measured across different frequency ranges and vertical axis Therefore any curve can contain data which is not necessarily in the same frequency range as that currently in use by the scale system of the program However there is a means to realign this data to the current scale frequency range or any other if desired Since the frequency data points contained in each curve may be different the data grid displays the number of data points frequency range and type of data for each of the curves The names used for curves can be set and or changed by the user When data is initially placed into the curves through various operations a default name will usually be created by the program For example when you import a curve from a file the file nam
42. amp white The resolution of the image is fixed at the time it 15 created While raster images are probably the most portable form of graphic representation they are very bulky and inefficient for high precision resolution Moreover printing low resolution raster image on a higher resolution output device does not improve the image quality The following industry standard raster formats are supported BMP Windows Bitmap Format JPG Joint Photo Experts Group ZSoft Picture Format PNG Portable Network Graphics MTIF Tagged Image File Format 168 LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu If you desire other formats use a paint type program to convert one of these into the other format There are many commonly available programs on the Internet as shareware which can do the job For more extensive editing capabilities PaintShop Pro or Adobe PhotoShop can most certainly be used Note We do not provide native support for the GIF format due to patent 4 558 302 issues involved with the Lempel Ziv Welch LZW compression algorithm owned by Unisys Corporation When using raster images you must choose a DPI dots per inch value which will determine the resolution With raster images it is very easy to produce extremely large files Be careful to note the Image Size parameter value given on the last line of the panel If you attempt to construct an image size that 15 larger than your availab
43. featuring log frequency resolution from 10Hz to 100kHz Two tracking filters are included for special purpose measurements orto increase SNR during SPL measurements by using their Bandpass filter functions The system is also capable of performing gated measurements to provide semi anechoic type data in reflective environments Programmable Oscillator Volt Freq Frequency con Convertor Counter Detector Filter Signal Gain Set Gated Peak Signal Detector 30 LMS 4 1 User Manual Chapter 3 Getting Started Getting Started 3 LMS Sample lib File Graph Analyzer Processing Utilities Scale View ToolBars Help SPL vs Freg P25 at 1M C13 at 1M D25 at 1M GP ATI Parking Lot 11 1552 A TE OA 7 252 S SVO Ke 28Ft 18 Pair 3wayimpl_ lib File Graph Analyzer Processing Utilities Scale View ToolBar Help 4 2 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K a woofer 1 58g m S mid 4 x 13 as Re NA Rig B 1 LMS 4 1 31 User Manual Getting Started Chapter 3 32 LMS 4 1 User Manual Chapter 3 Getting Started 3 1 The Ana
44. ls vertical lines between the zones of each curve entry C Program Files LM SSE xpartstest txt Browse The File Path panel allows you to choose the file name for ene the file to be exported It may be entered in the edit box or by use of the Browse button Export Curve Data 11 C13 Again Freg SPL Phase When you click the Ok button the file will be written If a file of the same name already exists you will be prompted to confirm the overwrite of that file A sample listing on the following page shows a typical file export The columns are delimited with commas for easy export into spreadsheet programs LMS 4 1 165 User Manual Apr 23 2668 Info4 X OR Ok OX OR OX Ok OR OX 1 0151308 0801 1 H815158E H081 1 03 051 0 01 1 046116E 6061 1 8619468E 681 1 8736260E 681 1 09 434 B8E 1 118918E H081 1 127728E B881 1 1548B8B8E 881 1 162138E H81 1 179728E B881 1 19758B8E H81 1 215718E B081 1 234118E 081 1 2528B8B8E H81 1 271768E BB1 1 291828E 081 1 318568E H81 1 33B84BBE d81 Sun 3 02 am Library Polar lib Curue 11 test txt Infot c Program Files LMS Export test txt Info File Created Apr 23 2660 2 51 AH Info3 File Imported Apr 23 2888 Sun DataPoints 552 Datalnits Hz Ohm Deg 6 68643 66E 666 6 68643 606E 666 6 68643 66E 666 6 68643 66E 666 6 68643 66E 666 6 686
45. periods of time as this will greatly reduce battery life The battery should be recharged as soon as possible to at least a reasonable level System Status This group box contains a number of readouts which display the current system status within the PAC unit This data is updated each time the link is activated or when the dialog box is re displayed Link Status displays verification of whether or not the PAC link is active Baud displays verification of the baud rate detected in the PAC unit Rev displays the revision code of the PAC internal computer LMS Port displays the port address of the LMS card installed in the PAC unit if one is found This field will show 0 if no LMS card is installed 12V Bus Voltage 12V Bus Voltage 5V Bus Voltage 5V Bus Voltage displays the actual measured supply voltages inside the PAC unit Battery Voltage displays the actual battery voltage inside the PAC unit External Voltage displays the actual measured DC voltage inside the PAC unit produced from the external power source This could be either from the AC line or from the 12VDC auto power connector Power Source This group box contains two readouts which display the origin of the operating power It shows if the unit is running off the internal battery or if the unit is running off external power AC line or 12VDC auto LMS 4 1 User Manual Chapter 6 Analyzer Menu 6 7 Macro Run Analyzer Analyzer x Parame
46. the fonts used in your design should be available on the computer s where the file is used However if the font is not available on the computer Acrobat Reader will substitute or synthesize the closest font automatically 171 Utilities Menu Chapter 8 172 LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu 8 4 Export Graphics to Clipboard Utilities MEE E E E E re Import Curve Data File Export Curve Data File Export Graphics to File Export Graphics to Clipboard The Utilities Export Graphics to Clipboard menu item will open a dialog which transfers the graph artwork to the Windows Clipboard The tool button as shown above on the Utilities toolbar can also be used to activate this item Curve Capture Curve Editor Macro Editor MOF Editar This function can be very useful when you wish to paste the graphics into another open application program The graphics are stored in the Enhanced Meta File format Not all word processing programs can place this kind of image but most graphically oriented programs should have little trouble It should be noted that the Windows Clipboard can only hold one item at a time When you transfer an item to the clipboard the previous item is discarded When the dialog opens the title of the graph appears Clipboard Graphics Transfer Graphic SPL vs Freq Cancel Help 173 Utilities Menu Chapter 8 The example belo
47. 1500 33 3345F Ok Cancel Help 11 Installation Chapter 1 1 7 Analyzer Calibration When the LMS card is first installed on a computer itis a good idea to calibrate the card at least once This is due to differences in supply voltages between different computers which can affect the operating parameters in the LMS system Running the calibration routines is also a good way of checking the system for proper operation Select the Analyzer Calibration menu item as shown here The File Graph 202020 Processing Utilities MS software provides two calibration routines INTERNAL pz Parameters Ctr and EXTERNAL Much of the LMS system is controlled via sweep Stat Stop software rather than hardware For this reason there are no Use OnO adjustments required on the actual card but are instead accom RAE plished through the software This process requires a minimum Microphone Setup of user involvement or other equipment qo PAC Interface Macro Run Note Before running either of the calibration routines always allow your computer to warm up for at least 15 minutes While the circuitry in the LMS card is temperature compensated it is necessary for the temperature offsets to be achieved before running these routines This will provide the best results Select the nternal option and then press the Run button The process will take about 5 minutes and the result should look similar to what is shown bel
48. 4 1 User Manual LMS 4 1 User Manual linear 151 linear frequency resolution 129 Linear scales 208 Linking 96 LL UR reference coordinates 178 LMS analyzer hardware 79 LMS INI 60 LMS EXE 254 LMS INI 4 64 197 LMS PAL 62 LMSINIT 264 Load QuickSet File 53 LOADLIB 264 LOADMIC 265 LOADQS 265 log 151 Log axis 208 loudspeaker 137 Lowpass 81 M M31 195 Macro Command List 273 Macro Command Reference 259 Macro Editor 193 macro language 253 Macro Programming 253 Macro Run 99 Macro Run Dialog 275 macro script programs 193 magnetic system 132 magnitude 70 Magnitude Offset 105 106 Major Div 67 208 MAKESPLZ 265 Map legend 39 mathematical operations 105 max min limit 158 Index MDF 4 94 MDF Editor 195 199 MDF file 195 Measuring Inductors amp Capacitors 343 Measuring Methods for Impedance 307 Measuring Methods for SPL 279 mechanical resonance 132 Memory 3 Menu Toolbars 233 MENUSCRN 265 Meter 33 Meter Filters 80 Meter On time 83 MICMAKE 265 Microphone Data Format 4 94 195 Microphone Setup 94 Minimum Phase Transform 117 Minor Div 67 208 Mirroring 118 Mmd 137 Mms 137 Model Simulation 139 modeless 79 Modifying the Mic Calibration Curve 337 MUL 265 multi path echos 279 multipliers SI 353 N NAMECURVE 266 near field 279 Near Field Measurements 283 near field measurements 149 new library 47 Node Editing 189 nodes 181 NOTEPAD 59 Notes amp Comments 75 3
49. Auto RollUp Analyzer Parameters will automatically roll up the analyzer parameters dialog when a sweep is started and roll it down when the sweep is completed Curves The Automatic Curve Notes enables transfer of the curve info fields from the first two displayed curves into the Note amp Comment graph fields This is a handy feature which automatically transfers and displays the extra curve info on the graph page However if you wish to create your own graph notes you will need to turn this off The Beep At End of Sweep function produces an audible beep when a sweep is completed The New Library Auto Color will create a rotating group of five different colors whenever a File New library is performed Scales The Automatic Labels option controls whether or not the system generates it s own labels for all scales automatically If this is enabled the labeling features in the Scale Parameters dialog are grayed out You can disable this if you wish to create special labels yourself The Auto Up Dn Right Vert Data option selects whether the right side vertical data in the curves is controlled by the scale adjustment functions It is common that you may not want the phase right vertical data to change with scale functions However if you have other data than Phase in your curves you may need to enable this features Cursor Style The bitmap used for the tracking cursor can be selected here There are several possible choices The blinking r
50. Cancel LMS 4 1 51 User Manual File Menu 52 Chapter 4 4 6 Revert File Fi New Ctrl N e tree pe E 8g e gj Reopen k Save Ctri 5 Gaves Revert The File Revert menu item allows you to abort the current library file changes and reload the last saved version of the library The tool button as shown above can also be used to activate this item Load QuickSet File Save Duick Set File Print Ctrl F Editor Preferences A dialog will be presented to ask you to confirm this action All changes to the library will be lost when the previously saved version is reloaded Cris Exit Question Revert ta last saved version wght lib LMS 4 1 User Manual Chapter 4 File Menu 4 7 Load QuickSet File File Hew Ctri M Open Ctrl Reopen Str FS Gaves Revert The File Load QuickSet File menu item opens a QuickSet file and loads the configuration data into the Analyzer sese 2 Fle Parameters dialog The tool button as shown above can also Print pun be used to activate this item as well as shortcut CTRL L Editor Preferences QuickSet files store configuration parameters from the Analyzer Parameters dialog E zit Ctrl File Load QuickSet File presents a dialog to choose the QuickSet file to load QuickSet files have an SET extension Load QuickSet File amp
51. Chapter 3 Getting Started These chapters will give you fundamental information about LMS and answer most of your fundamental questions These chapters will tell you about how to operate the LMS software for some of the more common types of situations you will be encountering very early on There are of course many more topics covered in the remaining chapters You can read these as needed when you encounter more questions about specific areas of the program Operating and understanding the Curve Library is of basic importance for all purposes You will need to know how to select curves what the notations mean and how to enabled disable curves for display Also understanding the operation of the Scale Parameters dialog will be of great importance The LMS4 software provides a wide array of scaling options and can display your curve data in a variety of different forms The three Applications chapters at the end contain a wide variety of useful examples and information These chapters should be reviewed so that you will know what tips and tricks are contained within them You may be trying to perform similar tests or measurements that will be covered in these sections If you run into questions about testing take a look in this chapter for additional help All of the manual contents are also available on line within the Help system LMS 4 1 User Manual Chapter 2 General Features General Features 2 LMS Sample lib File
52. Charged means that the battery is at full charge This corresponds to the Battery Charge LED on the control panel of PAC in the OFF condition Over Charging means that the battery 1s currently having its charge topped off by a controlled over charging cycle This corresponds to the Battery Charge LED on the control panel of PAC in the ON condition Fast Charging means that the battery 1s currently in the bulk charge cycle This corresponds to the Battery Charge LED on the control panel of PAC in the Flashing Fast condition Slow Charging means that the battery is currently in the conditioning charge cycle This corresponds to the Battery Charge LED on the control panel of PAC in the Flashing Slow condition In this state the battery voltage is very low and must first be brought up to a reasonable voltage before fast charging is possible If the charger never comes out of this state on an old battery then the battery probably needs to be replaced Discharging means that the battery is currently being discharged by the operation of the unit from battery power 97 Analyzer Menu 98 Chapter 6 The ChrgAmps text box shows the current in amps being used to charge the battery Maximum charging current is about 1 25 amps To fully recharge a heavily drained battery will typically take about 5 hours When the battery is in discharge this field will display 0 0 amps Note Never leave the battery in a heavily discharged condition for long
53. D AB AE ENT The Processing Fast Fourier Transform menu item will open a dialog which performs an FFT on a time domain library curve The tool button as shown above on the Processing toolbar can also be used to activate this item An FFT transforms a time domain response into a frequency domain response If the frequency domain result is to represent a transfer function then the time domain response must be an mpulse type response The time domain entry to be transformed is specified in the Source Curve list box The resulting frequency domain response entry is selected in the following list box When you choose the source curve the number of data points will be shown above the list box The number of data points produced in the frequency domain result curve will be 1 2 this value The frequency axis will be linear The curve list boxes provide selection of the library curve for the operations These special list boxes shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Fast Fourier Transform Parameter Source Curve Time Domain Data 4036 30 Impulse P25 1M Time Wot Phase Result Curve Frequency Domain D ataj 32 FFT Impulse P25 1M Tails Freg Volt Phase LMS 4 1 User Manual Chapter 7 LMS 4 1 User Manual Processing Menu The first graph below shows a typical Impulse resp
54. Entry List No longer supported in LMS version 4 Does nothing Example 100 LIBLIST Initializes the LMS hardware The LMSINIT keyword causes the hardware to be initialized factory use Example 100 LMSINIT E LOADLIB filename LiB Load a Curve Library File The LOADLIB keyword is used to load a curve library file into the system If no extension or path information is provided the program assumes the extension of LIB and a location in the LMS Lib folder Example 100 LOADLIB engr lib LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs B LOADOS filename SET Load a QuickSet File The LOADQS keyword is used to load a QuickSet file to set the analyzer parameters If no extension or path information is provided the program assumes the extension of SET and a location in the LMS Set folder Example 100 LOADQS spl set B LOADMIC filename MDF Load a new MDF File The LOADMIC keyword is used to load a new MDF file for the Mic Input If no extension or path information is provided the program assumes the extension of MDF and a location in the LMS Mdf folder Example 100 LOADMIC SN12345678 MDF MAKESPLZ SPLentrynum Zentrynum Create combination SPL Z entry The MAKESPLZ keyword is used to produce a combination SPL and Z curve entry This type of entry contains two magnitude curves SPL and Z The first entry number is that of the SPL curve and the second is that of the Z curve The Z magnitud
55. ITS Loudspeaker Measurement System User Manual Win32 Release 4 1 INEARX 5 E M S lt LMS 4 1 User Manual 2000 LINEARX SYSTEMS INC All Rights Reserved Tel 503 612 9565 Fax 503 612 9344 Printed in the United States of America July 19 2000 This document was produced on a Pentium Il A400 PC with WinNT 4 using Adobe PageMaker 6 5 Adobe Illustrator 8 0 Adobe PhotoShop 5 0 MathType 4 0 for mathematics typography and SnagIt 4 3 for screen captures Final masters were produced using an Agfa SelectSet 9000 image setter Help files were composed and compiled using Windows Help Designer 2 3 Contents License Agreement and Limited Warranty Carefully read all of the following terms and conditions of this agreement before opening and using the contents of this package The opening of this package indicates your acceptance of the terms and conditions of this license agreement If you are not willing to accept the terms and conditions of this agreement then you should return the entire product with the package seal unbroken to the place of purchase for a full refund of the purchase price Copyright Ownership Both the program and the documentation are protected under applicable copyright laws LinearX is the holder of this copyright Your right to use the program and the documentation are limited to the terms and conditions described herein Use of the software unless pursuant to the terms and conditions o
56. Manual Chapter 15 LMS 4 1 User Manual Impedance Applications The worst case impedance dips down to almost 3 Ohms at some frequencies The cable impedance is about 0 6 Ohms If we had not subtracted out the cable impedance the result would have been almost 20 higher than it should have been Subtracting the cable impedance should always be done whenever the speaker s impedance is low or when the cable is long This will produce the most accurate results Another means to accomplish this is by using the 4 Wire impedance measurement mode In this case both the Line Output and Line Input cables are used with both connected at the terminals of the speaker In this manner the Line Output cable impedance is removed from the measurement The method described here is known as constant current because the current through the speaker does not significantly change as it is dominated by the 500 Ohm LMS output impedance This is a low drive level test for impedance The previous method is very easy to apply and produces excellent results for most work However there are times when measuring impedance under true constant voltage drive may be desirable 309 Impedance Applications Chapter 15 310 A M P L F E R M VOLTAGE 100V RMS BLK Q 5 SPEAKER CURRENT 1 OUTPUT Zout 1 000 x 2 TM MAXIMU 15 3 Impedance by Constant Voltage One of the many uses for this type of test
57. Mat Used 0 0000 10 2 40 08 SPL Mat Used 0 0000 201207 10 2 40 0KHz SPL Hot Used 0 0000 201208 10 2 40 08 SPL Hot Used 0 0000 201209 10 2 40 08 SPL Mat Used 0 0000 201210 10 2 40 08 SPL Standard 380 Standard 180 LMS 4 1 199 User Manual Utilities Menu Chapter 8 Polar Convertor Only the Function and Deg or Freq column fields Library Curves P index pesarean wwe uen jou Ja require editing The remaining columns reflect NotUsed 0 0000 SPL Phase 1 LE S rere the data of the curve library entries Input Deg 0 0000 SPL Phase Output Fre l 0000 SPL Phase 4 0 Cn whe Notes AM ME The Function field has three possible selections Not Used 0 0000 SPL Phase eh tem Not Used Input Deg and Output Freq 3 Not Used 0 0000 SPL Phase 10 Not Used 0 0000 SPL Phase 1 NotUsed 00000 SPL Phase The Not Used selection simply indicates that the 12 Notlised 0 0000 SPL Phase 13 Not Used 0 0000 SPL curve is not involved in the conversion 14 0 0000 SPL Phase Standard 360 All Off Standard 180 The Input Deg selection is chosen for input curves containing the normal frequency response curves as measured at different radial locations around the transducer The position of each curve is then P Mm specified in Degrees Deg values can be ibrary Curves Inde
58. Quality Control PASS FAIL Testing 16 7 Measuring Inductors and Capacitors vs Frequency Contents Contents Contents Appendix 351 Appendix A SI Units 359 Index 357 X LMS 4 1 User Manual Chapter 1 Installation Installation 1 LMS 4 1 1 User Manual Installation Chapter 1 2 LMS 4 1 User Manual Chapter 1 LMS 4 1 User Manual Installation 1 1 System Requirements LMS is a Win32 application and runs under the MS Windows operating systems These include Win95A Win95B OSR2 Win98 Win NT4 and Win2000 NTS It will not run under older Win3 1 systems LMS also uses extensive graphics For best results a 1024 x 768 video resolution is suggested with at least 64K 16 bit color depth Advanced font support for both True Type and Adobe Type 1 fonts is also provided The program supports native exported graphics in many Adobe PostScript formats including PDF However to obtain all these features requires that Adobe Type Manager ATM be installed on your system The LMS card requires a full length ISA bus slot If you are usinga laptop computer which does not have slots you will probably need to use the PACA portable analyzer chassis This enables the LMS card to be placed in the PAC4 and then communi cation is handled across a serial COM port between the computer and PACA Recommended System Requirements Bi Full length ISA bus slot Win95 Win98
59. SPL Phase 47 Output Freq 5 0000K PolarConv F 5 0000K 180 0 180 0De SPL Phase 48 Output Freq 10 0000K PolarConv F 10 0000K 180 0 180 0De SPL Phase 43 Output Freq 20 0000K PolarConv F 20 0000K 180 0 180 0De SPL Phase 50 Output Freq 40 0000K PolarCony F 40 0000K 180 0 180 0De SPL Phase Standard 360 oft Standard 180 Phase 400 Solid 20 Phase 400 Solid 20 Phase 400 Solid 20 Phase 400 Solid 20 Phase 400 Solid 20 LMS 4 1 User Manual Chapter 9 LMS 4 1 User Manual Scale Menu Scale Menu 205 Scale Menu Chapter 9 206 LMS 4 1 User Manual Chapter 9 LMS 4 1 User Manual Scale Menu 9 1 Parameters Parameters Fe The Scale Parameters menu item will open a dialog which controls all of the horizontal and vertical scales used for the main graph in the program This dialog allows you to specify the range and resolution of each scale The shortcut key F7 or tool button as shown above on the Scale toolbar can also activate this item The Scale Parameters dialog consists of two principal groups of controls Horizon tal Scales and Vertical Scales A different scale is defined for each type of curve units The horizontal panel provides control over the frequency time or angle unit scales The vertical panel controls a wide variety of different types of unit scales Labeling of the scales is by default handled automatically If you wish to perform manual labeling go to the File P
60. SPL Phase 0 Solid 20 5 No SPL Phase 0 Solid 20 O SPL Phase 0 Solid 20 Ll No SPL Phase 0 Solid 2 8 SPL Phase 0 Solid 20 38 No SPL Phase 0 Solid 2 10 No SPL Phase 0 Solid 20 1 O SPL Phase 0 Solid 2 12 1 No SPL Phase 0 Solid 2 E Cancel Help LMS 4 1 User Manual Chapter 3 2 LMS Untitled_lib Getting Started Note Only curves of similar units can be displayed on the graph simultaneously The type of data units for display are defined by the first enabled curve in the list If you attempt to display mixed curve types curves which do not match the first enabled curve will be automatically disabled from display For example you cannot display an Impedance curve at the same time with an SPL curve The types of grids and scales would not be compatible The Data Curve is the location of where the data of the next sweep taken will be stored This is a pair of angle brackets around the index number of the curve in the grid box table It is also displayed in an edit field shown in the upper left hand corner The data curve can be selected using the edit field or simply by double clicking on a curve entry in the table When a new data curve is selected it is also automatically enabled for display The remaining columns in the table show a variety of information about the curve entries Each curve can be given a name and there is additional information that can
61. User Manual Chapter 4 LMS 4 1 User Manual 4 9 Print Hew Ctri M Open Ctrl Reopen Str FS Gaves Revert Load QuickSet File Save QuickSet File Editor Preferences Exit Ctrl File Menu File amp The File Print menu item is used to print the main graph window data The accelerator key CTRL P can be used to activate this item using the keyboard or the tool button as shown above The Print item opens a dialog for printing control From here the artwork generated in the program can be printed to any output device currently supported in your Windows system The graph used in the program has a layout of 10 inches wide by 8 inches high Printing at a scale factor of 100 will require landscape orientation on 8 x 11 letter size paper This is the default mode for the printer setup For portrait printing use a reduced scale factor such as 80 or less Printer Configuration This panel displays the configuration for the currently selected printer When you start a print this configuration will be used To change the configuration use the Setup button at the bottom of the dialog box Printer Configuratio Printer Port LPT1 Printer M ame EPSON Stylus COLOR 600 Orientation Portrait Paper Size Letter 85xllln Spectrum CCC Device Dry ECPDJS3DLL Y2 0000 Cancel Setup Help Color Option f Color or Gray Black amp White
62. Win95A 3 Win95B 3 Win98 3 Windows colors 26 Windows Metafile 169 WME 167 LMS 4 1 365 User Manual Index 366 LMS 4 1 User Manual
63. a dialog which derives numeric electromechanical speaker parameters from one or more impedance curves The tool button as shown above on the Processing toolbar can also be used to activate this item This dialog provides five different methods of generating speaker parameters Moreover the parameters generated can be produced for two different models Standard or LEAP The dialog also provides the means to generate impedance curve simulations based on the derived parameters This allows for easy viewing and comparison of the model to the actual measured impedance data Four buttons are provided in the Operation panel There are three phases to the parameter derivation estimation optimization and simulation The large button runs all three phases with a single click However if you wish to run or rerun each phase individually the three smaller buttons provide this capability pj hedialogcontains anum aaa ber of small arrow buttons Reference Curve 2 woofer 1 Reve 5 72 Freq Phase above the edit boxes which Delta M C Curve 3 woofer 1 58g Freq can be used to change the Frees Reve Ohm Sd sqM Yab cuM Md units for a particular field C Inf Baffle 5 720 34 000m j 1 000 50 000 The curve list boxes pro vide selection of the library 12108 3 1 000K 4 855 curve for the operations These special list boxes 26 673 4 45m 12 108m 1 000
64. a name for the library If it already has a valid name that name will be kept When saving library files it is generally best to create a project folder under which all of your files for that project can be placed This can include imported exported data files graphics files etc Library files have an extension of LIB You should always use the default extension Itis notrecommended that you use other extensions or you may not recognize the files in the future LMS 4 1 User Manual Chapter 4 File Menu 4 5 Save As File ax New Ctrl N ae Ctrl 0 Pe E E d BH e gj Reopen k Save Ctri 5 The File SaveAs menu item saves the current library under a new name The tool button as shown above can also be used to activate this item A dialog will be presented to specify the file name and or folder Revert Load QuickSet File Save GuickSet File Print Ctrl F Editor Preferences When saving library files it is generally best to create a project folder under which all of your files for that project can be placed This can include imported exported data files graphics files etc E zit Ctrl Library files have an extension of LIB You should always use the default extension It is not recommended that you use other extensions or you may not recognize the files in the future Save Library File Save n CX Lib File name Save as type Library Files
65. a pair of curve entries where the simulation curves can be placed After clicking the Estimate Optimize Simulate button an estimate of the param eters is derived from the input data and then optimized for best fit The simulation curve is then placed into the specified library curve entry The following page shows an example of a typical parameter set generated for the LEAP model The input curves are shown in Blue and the model simulation curves are shown in Red The resulting parameters are Md was 45 g Revc 3 12 Ohms Fo 37 8 Hz Sd 0 0856 sqM Krm 4 58 mOhm Kxm 10 7 mOhm Erm 0 701 Exm 0 690 Mmd 56 2 g Mms 70 6 g BL 11 38 TM No 3 4 SPLo 97 3 dB Cms 252 uM N Vas 0 262 cuM Qms 3 78 Qes 0 40 Qts 0 36 139 Processing Menu 140 Chapter 7 A simulation is produced for both the reference and delta curves The simulation curves show a close match to the original data for both the reference and delta curves This result is fairly typical for most loudspeakers These parameters were generated for the LEAP model Speaker Parameters Metho Single Curve Elec Motor Curve Elec System Single Curve with Mmd Double Curve Delta Mass Double Curve Delta Comp Model Parameters Data Transfer R EYE Fo 5 8 99 600m Ohm 3 120 Hz 56 221 mi Krm Erm Input Parameter Reference Curve 1 15 FA Reve 3 12 Fre
66. a sweep measure ment The tool button as shown above can also be used to activate this item or the shortcut key F9 Selecting the menu item tool button or shortcut key again will start stop the sweep The ESC key can also be used to stop a sweep When a sweep is started it is based on the parameters as defined in the Analyzer Parameters dialog The selected Data Curve will be loaded with the sweep data 89 Analyzer Menu 90 Chapter 6 6 3 OSC On Off EBLDBSG Parameters Fh Sweep Start Stop sc On Off ALC Meter Microphone Setup PAL Interface Macro Hun Calibration The Analyzer OSC On Off menu item will toggle the oscillator Line Output On Off The tool button as shown above can also be used to activate this 1tem or the shortcut key F10 Turning the oscillator On Off by the method described here pertains only to fixed frequency static measurements The oscillator is automatically turned On during a sweep LMS 4 1 User Manual Chapter 6 Analyzer Menu 6 4 RLC Meter Fh 2 59 Parameters Sweep Start Stop Ose On Off F1 ALC Meter Microphone Setup PAC Interface Macro Run The Analyzer RLC Meter menu item will open a dialog which performs resistance inductance and capacitance mea surements The tool button as shown above can also be used to activate this item Calibration The RLC Meter utility will measure resistance inductance or capac
67. at any of three locations the top control bar the Toolbox or as single floating windows When a toolbar is added or removed the control bar or tray will resize When all ofthe toolbars are removed the control bars will collapse down to minimal height The user may arrange the toolbars in whatever fashion is desired Generally only the most heavily used functions have toolbars enabled for display Displaying all of the toolbars on small screen size 800x600 can use up valuable pixels If you have a large screen then more toolbars can probably be displayed without difficulty Toolbars can be arranged in single rows or multiple rows Sea 233 Toolbars Menu Chapter 11 234 LMS 4 1 User Manual Chapter 11 Toolbars Menu 11 4 Status Bar The status baris shown along the bottom ofthe main window The baris sub divided into a number of different smaller panels These panels will now be described from left to right 100 ats Re amp TESTNG 11428 Hz 408768mdBm Lei LMS 4 1 User Manual Zoom This panel shows the current zoom level of the main graph in percent Abs Rel These two buttons are used to switch the tracking cursor between absolute and relative readout mode When the cursor 15 in switched to relative mode a marker is dropped at the current position of the cursor When the cursor is moved the readouts display the relative difference between the reference position and the new position
68. be stored with each curve as well Other columns provide information about the type of data in the curve number of data points and the line attributes for the curve Most of this is self explanatory and will not be covered here in any further detail For more information about the Curve Library see the Graph Menu chapter For now just exit the Curve Library dialog using the Cancel button We are now ready to start the sweep Select the Analyzer Sweep File Graph Processing Utilitie Scale View 2 Hoa Parameters Sweep Start Stop Osc On Off ALC Meter Microphone Setup PAC Interface Macro Run 0 Calibration Sweep Button 2 LMS Untitled lib LMS 4 1 User Manual Start Stop menu item Note that a shortcut key F9 can also be used to activate this function A tool button is provided as indicated by the Red dot which turns Green when a sweep is active When the sweep starts the status bar at the bottom of the screen will display a progress meter A message is also displayed which informs you how to stop the sweep using F9 or ESC As the sweep progresses a blip marker is shown at the leading edge of the curve as it is being drawn on the graph In a case like this where no previous data curves exist on the graph the scales may not be in a position where the new sweep data is visible while it is being drawn It may be at the top or bottom of the graph However once the sw
69. button will produce a standard setup for 36 11 Input Deg 35 0000 SPL Phase 12 _ InputDeg 30 0000 SPL Phase input curves covering 5 Deg radial resolution 13 Input Deg 25 0000 SPL Phase 14_ ImputDeg 200000 SPL Phase gj across the 90 range There will be 14 output ES curves in 1 2 octave intervals from 40kHz and Dk Cancel Help lower 200 LMS 4 1 User Manual Chapter 8 dBSPL 4 Utilities Menu The standard setup buttons provide an example of how to setup the polar conversion process and its parameters However in many cases you will wish to modify or change these values for your own specific purposes There is no particular order required for either the input or output curves They can be mixed or out of sequence in any order The conversion routine reads the Function and the Deg or Freq values to determine whatis contained in each curve and applies automatic sorting to properly construct the polar response output curves Example of Polar Conversion To illustrate how this utility can be used an example is probably the best way to demonstrate the process The directivity characteristics of a 1 2 Inch microphone are to be measured A series of ground plane De measurements were HT Lilli made by rotating the mic by 7 5 Degree incre ments through the entire SPL vs Freq 120 360 Degree circle This resulted in 48 frequency 60
70. data into the software This will enable accurate SPL measurements Once loaded the data 1s saved in the LMS INI file and will be retained and used whenever the program is started LMS 4 1 User Manual Chapter 1 1 3 Hardware Installation IBM PC ISA EISA Expansion Bus 1 0 Port Map 200 3FF Hex 01234 56789 ABCDEF Game Controller 3270 PC Network Card BiSync Comm 2 390 OF 3A0 SBiSyCommi 3AF 3B0 3BF 3C0 EGA VGA Video 3CF 3D0 CGA Video 3DF SEO Reserved 3F0 01234 56789 ABCDEF 370 37F LMS I O PC Port Map LMS 4 1 User Manual Installation Note The LMS analyzer card has several parts that are static sensitive and may be damaged by the static electricity that may have built up in your body The best way to assure that no damage comes to your analyzer is to observe precautions First handle the card by the edges avoid ing contact with any of the copper traces Secondly make sure to ground yourself This can be done by touching any metal surface such as the computer chassis Before your LMS card can be installed the proper I O Port Address must be selected The LMS card has four pos sible port addresses which are selectable by setting the jumper positions on jumper pins and P2 The base port addresses are 21F 25F 31F and 35F Port Selection Installation Chapter 1 A detailed description of the LMS port locations as well as other assigned PC
71. delay To measure each of the individual response curves two of the three drivers in the enclosure are disconnected from their crossover sections for each sweep The response curves for each of the three ranges are shown on the next page The frequency range used here is 10Hz to 40kHz Looking at the curves in the top graph it should be noted that the roll off amplitudes in the stop band regions of each response do not continue to fall as they should but of course limit out at the noise floor of the environment Note that on the midrange and tweeter curves there is ahump shown at 30Hz of about 70dB This was background noise caused by an air conditioning unit This must be corrected before the phase is generated This is done by using the Tail Correction utility The Woofer curve is corrected above 9kHz The Midrange curve is corrected below 60Hz and above 9kHz The tweeter curve is corrected below 1200Hz and above 35kHz The resulting corrected curves are shown in the lower graph These corrections do not affect the magnitude data in the pass band regions but are vital to producing correct minimum phase data iili ie 200 Complete Full Range Response of 3 Way System LMS 4 1 User Manual SPL Applications Chapter 14 midrange and woofer curves This can be done by using the Processing Unary has been completed the appropriate delay values must be combined into the Math Operations dialog with the Delay Offset op
72. design The figure below shows two curves produced from shorting the output lines together and by leaving them open circuit A frequency range of 10Hz 100kHz is used Theareabetween these two curves represents the region where the system can take valid inductance measurements Outside of this region the system is limited by the maximum impedance it can measure 1000 Q and the interface cable resistance 0 3 Q Inductance vs Fre E H 0 Inductance Measurement Range 347 Misc Applications 348 77 16 The range shown here only covers the inductance scale from 0 3mH to 30mH By projecting the limit lines to both higher and lower values one can easily judge what frequency range will be required to test a given size inductor Large inductors will require low test frequencies and small inductors require high test frequencies The usable measurement range for inductors is approximately 0 01 mH to 1000mH Inductor Curve Examples The graph below shows five examples of different inductor curves 9mH powdered iron bobbin 5mH powdered iron bobbin 4mH laminated iron bar 1 5mH air core and a 0 75mH air core All of the chokes have different DC resistance values ranging from 0 3 to 0 9 Ohms Looking at the curve for the 9mH choke we see that the curve rolls up at the low end from 10 20Hz due to the resistance of the cable and choke and reaches the 1000 O
73. enabled both for a frequency horizontal object and value vertical object the cursor will be snapped to the common intersection whenever possible When snapping to a Library curve tracking may become difficult if the slope of the curve reaches high values This can happen on the nulls of elliptic response or similar sharp transitions The vertical density of points may be too low to provide continuous tracking Snapping to the grid occurs at both major and minor divisions The number of divisions on the Curve Editor graphs are the same as those defined for the main system graph 185 Utilities Menu Help oom In zoom Out v oom 100 oom U0 oom 400 oom BUDE Redraw EditMode Question oom In oom Out Insert Made Delete Mode Select All Lave Revert Shift dd Shift Sub Shift F Shift F 2 Shift F4 Shift F8 186 Chapter 8 View Menu This menu provides different commands for changing the display scale factor The Zoom In and Zoom Out menu items will change the cursor icon and allow you to drag arectangle around a region of the graph to zoom The Zoom NNN items provide instant zoom to the specified value The center of the graph will be maintained Redraw will refresh the display Tool buttons are provided for each of these menu items Note An alternate method of instant zoom is also provided using the Add Sub keys in the numeric keypad on the keybo
74. factor in dB then take 20 Log of this value If you wanted to scale the near field pressure to a far field equivalent for a full space environment anechoic you would divide this ratio by 2 or subtract 6dB MIC PORT Mouth of Port LMS 4 1 User Manual Chapter 14 SPL Applications The following example should help to explain the process This enclosure used a 15 woofer and a port of 4 5 in diameter The following scaling constants are produced 15 Woofer Sd 0 089sqM Pf Pn 0 0842 21 5dB 4 5 Port Sd 0 010sqM Pf Pn 0 0286 30 9dB The figure below shows the raw near field curves taken at the port and woofer before scaling Note the woofer null at 40Hz where the port is tuned Also note that the port curve is higher than the woofer curve This is because the area of the port is smaller than the speaker Now the curves are scaled down The woofer curve is shifted by 21 5dB and the port curve is shifted by 30 9dB The scaled curves are shown in the top graph on the following page Now the amplitudes of the port and woofer show similar levels The next step is to generate the phase curves for each The only precaution which should be observed here is that the slopes of each curve as they cross the low frequency limit be at the asymptotic rate of 12dB Octave For this example the woofer curve was fixed using the Tail Correction utility at 25Hz and was set to 12dB Octave 130 on SPL vs Freq
75. hardware card has a complete software routine which calibrates all of the different sub systems within LMS LMS should be calibrated each time the card is installed in a new computer Beyond that it should not be necessary to re calibrate the instrument although periodic monthly yearly calibration is not unreasonable especially in a production situation Note Be sure to warm up the system at least 15 minutes first The nternal calibration procedure does not involve any outside connections or operations The memo area will display the various tests being performed and give a pass fail tag as each 15 completed as shown below Calibration requires about 5 minutes If your system fails many of the calibration tests you probably have an I O address conflict be tween the LMS and some other card in your system Change the I O port jumpers on the LMS card and run the calibration tests again If the calibration tests still fail try another address If Analyzer Calibration E fe Estemal Internal Calibration Parameter Under Tes FregScale 0 18 000 Index Internal Calibratian Working LMS I O port 021 the condition continues there may be a problem Trnsfr Patio 251 937 uV Hz PASSED Attenuator Scale 259 968 mdB Step PASSED with your power supply or other local interfer AutoBange Gain 1 3 986 Vs PASSED AutoBange Gain 2 10 116 V V PASSED ence Gate
76. here is from about 20Hz to 10kHz The capacitance curve in this region is quite flat and shows little frequency dependency on its value The 60uF electrolytic curve is of most interest Note that the curve would not intersect with the lower limit projection until a very low frequency far below 10Hz There is a significant downward slope to the curve in the valid range from 10Hz up to 2kHz From there the curve rolls into the cable resistance limitation at higher frequencies The electrolytic capacitor does not show the same kind of flatness as did the mylar film capacitors The value is more frequency dependent Electrolytic capacitors do indeed have higher dissipa tion factors internal losses than do film capacitors and larger frequency coefficients LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications Inductor Range When viewing the inductor value curves produced from a sweep across a frequency range it is important to recognize the limitations of the measurement system and setup There are two basic limitations 1 the LMS system will clamp the maximum impedance to 1000 Ohms and 2 there is always a cable resistance present of about 0 3 Ohms in series with the component These two limitations define the maximum minimum measurement range for the system However even with these limitations 70dB of impedance measurement range is provided and covers the region most commonly used by inductors for crossover
77. image will appear either in the middle of the page or in the top left corner The Center of Page positions the artwork in the center of the available printing area The printing area is dependent on the page size selected for the printer The Corner of Page option positions the artwork at a corner of the available printing area The printing area 15 dependent the page size selected for the printer and the specific corner will very depending on whether landscape or portrait orientation is in use LMS 4 1 User Manual Chapter 4 File Menu Scaling Options This editing field allows you to specify the amount of enlargement or reduction in the magnification of the printed image The value is entered in percent A full size 100 plot represents an artwork width of 10 inches and a height of 8 inches for the standard sized graphs Setup Button Use this button when you wish to change the selected printer and or configuration When this button is pressed another dialog will open to change the printer port selection These dialogs are produced from the printer driver The contents of these dialogs will be different for various printers An example is shown below Print 5etup HE Properties Ready EPSON Stylus COLOR 600 Comment Orientation Portrait Size Letter B1 22a11in Source auto Sheet Feeder Network Cancel Landscape LMS 4 1 57 User Manual File Menu 58 C
78. in Fo due to the delta mass The resulting parameter set is the full electrical and mechanical values For this method the radiation domain must be selected as either Free Air or Infinite Baffle The radiation mass Mmr of any speaker is dependent on the air load and this is different for these two domains For speakers mounted and measured on IEC baffles or other large surfaces the Infinite Baffle selection is appropriate If the speaker is held in free air or clamped to an open frame structure the Free Air selection should be chosen The parameters for Revc Sd and Vab must also be entered Revc is the DC voice coil resistance as typically measured with a DMM The Sd value is the piston area of the speaker You can click the Ellipse button for another dialog which will compute the Sd value for you based on diameter or radius The Vab value is the volume of the test enclosure You can click the Ellipse button for another dialog which will compute the Vab value for you based on dimensions You must also select the two library curves locations for the reference and delta impedance curves In the Model Simulation panel choose a pair of curve entries where the simulation curves can be placed After clicking the Estimate Optimize Simulate button an estimate of the param eters is derived from the input data and then optimized for best fit The simulation curve is then placed into the specified library curve entry The following page shows an
79. interpreter Each statement line of the program is read decoded and executed in a linear sequence As with BASIC program lines must start with a line number Line numbers are used to reference and report errors and as labels for GOTO statements The macro command keywords and variable names can be either upper or lower case Comments and messages will be displayed exactly as they are entered Text messages are always entered between double quotes All keywords and parameters must be separated by one or more spaces The maximum number of characters per line is 255 Comment lines can exceed this since they are not used by LMS However messages to be displayed on the screen will be truncated if the total line length exceeds 80 chrs The maximum length of the program is limited to 4096 lines which is usually more than adequate A sample program is listed below The general syntax of each line is as follows LineNumber KeyWord Parameter s 100 WORKMSG This is a message in the work area 10 Title LMS Macro test Program for Development 20 Date 11 10 91 30 Author Strahm 40 Description This program is for testing macro keywords 4 6 50 WORKCLR 60 COMLCLR 70 GOTO 80 80 COMLMSG This is a Command Line Message HELLO 110 WORKMSG I am Now going to wait for 5 seconds 120 WAIT 5 130 INPUT Enter in t
80. item will open a dialog which allows you to load Microphone Data Format MDF files into the system The tool button as shown above can also be used to activate this item Calibration MDF files define the acoustical to electrical relationship of the mic sensitiv ity and also contain the actual response of the microphone The system uses this data to calculate true SPL levels and to correct the response of the mic When you load an MDF file the data is retained and stored in the LMS INI file and restored each time the application program is started You should not need to reload an MDF file unless you change the microphone or the LMS INI file is replaced Both the Mic Input and Line Input support MDF file definitions The Mic Input is typically used with the included M31 microphone During the program installation you were asked if you had an MDF disk If you answered YES then that file was copied to the LMS MDF folder You should load the file located in that folder to setup the software for use with the Mic Input If you are using a different external microphone with the Line Input then you will need to create your own MDF file See the chapter on Utilities MDF Editor for this requirement Operation of this dialog is very straight forward Simply click the Load MDF button for either the Mic or Line Model MST AcousicRef 340000 SPL inputs Locate the MDF file probably in the LMS MDF Serial 123456 ElecticRef 38
81. measurements to cover the mid and high frequency regions This operation allows a finished combined result to be produced using data from both Bothlow high data curves must be of the same type ofunits These cannot be mixed The units of the result curve will be the same as those of the low high data curves The frequency points will be the same as the low curve below the splice frequency and the same as those of the high curve above the splice frequency If the two low high curves were not of the same frequency range then the result curve points will not have consistent frequency density This can be corrected by using the Data Realign processing operation This can be done directly in the curve library or from the Processing menu Data Splice x Farameter Source Curve For Higher Data 3 025 at 1M Source Curve for Lower Data 1 P25 at 1M Result Curve 21 Spliced 1 5500K Horz Splice Transition 1 5500 Cancel Help LMS 4 1 User Manual The curve list boxes provide selection of the library curve for the operations These special list boxes show the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Freq SPL Freq SPL Phase SPL Phase The splice frequency should be chosen at a point where the curves have similar if not identical values The cursor system can be v
82. must be colored differently than other items The graph axis should be square with the image boundary The first requirement can easily be achieved by use of a Paint program which can perform the needed file conversion If the original file format was TIF JPG PCX GIF etc use of a Paint program is required to convert the file to BMP Many such programs are commonly available on the Internet as shareware The second requirement involves image color The capture process picks the curve out of the image by a color matching technique The color of the curve must be somewhat unique to enable it to be identified from other items in the image For handling images that are Black amp White they must be imported into a Paint program where the curve can be colored manually as needed The last requirement is that the graph on the image not be rotated or skewed The processing routines assume that the graphical image is square with the edges 175 Utilities Menu 176 Chapter 8 Horz Dat Left ert Dat Fight Vert Dat Freg C Linear Log fimp C Lin Log C dB Phase Lin Log C dB Polar Freq Hz Prefix Units dB Ref Prefix Units dB Ref Prefix Units 1 0000 Hz 10 711 Ohm 10 zj Deg Graph Imag Reference Point Data Upper pun LL Coord UA Coord Left Curve Right Curve a Pisel Coord XY 28 L L L TT z 110430 40 0000K Ohm Right Vert Deg 30 0000
83. of the Car response all three curves will now be leveled with a 1 2 octave factor The leveled curves are shown in the graph below Now the sharp interior reflections are removed and the basic frequency response can be seen a 5 i 1 2 Octave Leveled Responses 293 SPL Applications 294 Chapter 14 To see what the environment of the car looks like relative to the controlled ground plane measurement both of the car response curves are each divided by the ground plane curve producing the ratio transfer function curves shown in the graph below The curves were scaled to produce a normalized response in the mid and high frequency area of OdB As shown below the response in the car rises by about 12dB Octave below frequencies of 200Hz This is the transition region where the environment changes from a free field to a constant pressure field There are also some very strong standing waves inside the car causing the large peaks and dips No doubt these are probably due to the wall sides and windshields SPL vs Freq ee px epos EE CR ER NICE LEJOS EXGCES EEE Ee Ee ERES Depos cpm e EES CCE
84. on the computer where the file is used LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu EPS Formats The EPS format is very popular for professional graphics They contain PostScript vector code to produce the final high resolution output and also contain a low resolution TIF raster image preview The two EPS formats provide both gray scale Black amp White or full CMYK color The fonts used in your design must be available on the computer where the file is used Al Format The Adobe Illustrator format technically requires Adobe fonts If you have assigned TrueType fonts in the program to some text items you will receive a warning message when you open the AI file in Adobe Illustrator of an unknown font However you can easily reassign the font as needed in Illustrator or other drawing programs Other graphics programs often ignore the font name informa tion altogether The fonts used in your design should be available on the computer where the file is used PDF Format The Adobe Acrobat PDF format is becoming heavily used on the Internet for documentation download The format is very powerful very efficient and viewable by almost everyone using the free Acrobat Reader The files also use ZIP compression which makes them very small and easy to attach to emails While the PDF format contains the ability to embed the fonts directly this function is not supported at this time with this version of LMS Therefore
85. operator of something The message parameter should be in double quotes The first work area message will be placed at the top of the work area Each following work area message will be automatically placed on the next line below When WORKCLR command is given this process repeats After a WORKCLR command the next work area message will again be placed on the top line ZCURVEFO entrynumber Fo tol compare Fo to tol The ZCURVEFO keyword will run a comparison test on a speaker impedance curve resonance for Fo This operation sets the internal Pass Fail flag which can be used with the ONFAILGOTO command This example tests curve number 11 for Fo 28Hz 5 Example 100 ZCURVEFO 11 28 0 5 0 ZCURVEZO entrynumber Zimp tol compare Zo to tol The ZCURVEZO0 keyword will run a comparison test on a speaker impedance curve resonance for Zo This operation sets the internal Pass Fail flag which can be used with the ONFAILGOTO command This example tests curve number 11 for Zo 55 Ohms 10 Example 100 ZCURVEZO 11 55 0 10 0 271 Macro Programs Chapter 13 2 2 LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs 13 8 Macro Command List The following is a summary listing of the LMS macro commands For any new possible updates check the README MAC file in the LMS MAC folder for any possible additional new commands ADD COMLMSG COMPARE 4 COPYCURVE CURVEUNITS
86. port locations are given in the previous LMS PC IO Port Map Choose one of the port locations and set the jumpers accordingly If you are not certain of the port locations of other devices operating on your computer s bus start with location 21F If erratic behavior is encountered you may wish to try another port address The software driver automatically detects the presence of the LMS card and its I O base address The application software obtains this information to setup the LMS analyzer Note If you have tried all port addresses and still see erratic readings you have a high memory problem or a power supply problem Consult your Device Manager in the Windows Control Panel to check for memory conflicts C383 C316 C308 E NN uM ELE z U307 D ueva uega uege U2g1 m U2g4 E t320 R316 C307 g C301 R43 x 01 or 02 A Re R4 q myn ole C3 2 329 03101 R315 D C341 uses uses Cee Ces C24 Ce3 XJ U324 ule 3 X C380 C381 m 15 remace 9 BART
87. s now go back to the analyzer control panel Select the Analyzer Parameters item from the menu or use the tool button or F5 As shown below one of the group panels in this dialog is called Sweep This panel contains a list box titled Data Curve This allows you to choose the data curve for the next sweep justas you would in the Curve Library dialog Providing this function here eliminates the need of having to leave the Analyzer Parameters and open the Curve Library There are several other similar features offered in this panel You can set the Name for the data curve here as well Also by pressing the Graph button you can select the data curve for display alone and disable all other curves Another commonly used feature is to take static measurements from this dialog You can turn the Oscillator On Off by using the lower left hand button This function is also provided on the main menu and on a tool button If you have a requirement where you wish to manually adjust the oscillator frequency the slider control in the Oscillator group panel provides this capability The dialog also features several buttons which perform automatic unit conver sion By clicking the unit button you will be cycled through a list of units Analyzer Parameters Mad Hi Speed Data Precision Data Meter Filter 1 Filter Functian Fiat Track Ratio 1 000 448 813 Oscillata Output Level 6 000 Frequenc
88. shows the number of the entry from 1 to 50 When an entry is selected as the data curve a pair of angle brackets are shown around this number The data curve entry can be selected by double clicking on an entry or by using the Data Curve edit box The G column provides an array of check boxes which are used to select the curve entry for display on the graph The Name column can be edited to enter a name for each curve entry T1 Graph Menu Chapter 5 The nfo column provides access to some additional notes which can be attached to each curve If there are additional notes the field will say Yes Click on the ellipse button to open the info editing dialog The Horz Data Range column provides an abbreviated message giving the range of horizontal data If it is a frequency axis it will show the lowest and highest frequency values in the curve You can click on the ellipse button and another dialog will open which allows you to realign the data to a different frequency range log or linear axis and number of data points For more details on this function see the Processing Data Re align chapter and section Curve Healign Curve Parameter E13 at 2H SPL Phase Linear Paints Harz La Limit Harz Hi Limit Log 552 10 1514 39 994 5K Cancel Help Interpalatio Linear C Quadratic Cubic The Left Vert and Right Vert columns provides the ability to change the type of vertical dat
89. space bar or enter key as needed to perform another test All other program functions are preset in the program including changing screens files and entry numbers Custom Adjustments for Improved Speed Much of the LMS system s operation is controlled by many software parameters in the File Preferences dialog box The default settings provide the best overall performance and speed for a wide variety of possible tests These parameters can also be programmed from a macro However if a limited number of specific tests are to be run on a regular basis improvements can be made for these dedicated tests Many times speed improve ments of 100 to 500 can be realized SCP 40 41 42 45 44 45 These are time parameters which allow the system to settle after ranging changes over frequency This allows small DC offsets within the system to settle out in order to provide for maximum accuracy at low level signal measurements In many cases where the signal strength is strong these values can be decreased substantially without significant loss of accuracy This will speed up the system sweep Because of the diverse nature of possible tests and set ups no general specific recommendations for values can be given for all circumstances The ability to increase the sweep time will largely depend on the data being measured If the data is at very low levels the settling parameters will play an important role in controlling accuracy Ifthe signal levels be
90. the assigned MDF data for either the Mic or Line inputs Impedance The impedance data type is specifically intended for measuring the impedance of a loudspeaker or many other passive electrical devices The measurement is based on the 500 Ohm output impedance of the line output and the resulting voltage divider formed with the load Either the Line Output or Line Input can be selected for 2 Wire or 4 Wire impedance measurements respectively LMS 4 1 User Manual Chapter 6 LMS 4 1 User Manual Analyzer Menu Since the oscillator output is being taken via the analyzer s internal 5000 load resistor the impedance measurement is the voltage divider type The LMS system will automatically remove the effect of the internal 500Q source and record the level in actual Ohms Inductance Capacitance These data types produce measurements which contain either Henrys or Farads The setup for these data types would be the same as that of impedance The computations assume that the impedance being measured is a pure reactance This is different from an RLC bridge which separates the resistive component Measuring reactive components with LMS is somewhat more complex than using an RLC bridge or meter and the user should study the pertinent information provided in the Miscellaneous Applications chapter Polar Volts The polar data type is used to perform a true polar sweep The oscillator frequency is held constant and the TTL output is pulsed f
91. the detail of a curve The first parameter is the entry number for the curve to level and must be an integer 1 through 50 The second parameter is the octave width to apply to the leveling process and is a real number The larger the octave number the more the curve will be leveled Example 100 SMOOTH 12 0 5 B SORT entrynumA entrynumR SQRT A R The SQRT keyword is used to produce a result curve that is the square root of another curve All parameters must be integers and between 1 through 50 This is the equivalent of taking the square root of a curve Example 100 SORT 11 15 269 Macro Programs 270 Chapter 13 B SUB entrynumA entrynumB entrynumR SUB A B R The SUB keyword is used to produce a difference result curve from two other curves All parameters must be integers and between 1 through 50 This is the equivalent of subtracting the curves A typical application might be subtracting an impedance curve measurement from another curve with the cable ends shorted to produce a resulting curve which is purely the speaker s impedance without cable impedance Example 100 SUB 11 12 15 SWEEP RunsaSweep The SWEEP keyword is used to initiate a sweep If the MacroRun dialog is currently rolled down it will then be rolled up Example 100 SWEEP B RATIO entrynumA entrynumB entrynumR DIV A B R This keyword is an alternate for the DIV command Example 100 RATIO 11 12 15 VARLABEL var var var Declares vari
92. the resistance andreactance quantities It therefore assumes in the calculations that the impedance being measured is entirely reactive Most inductors and capacitors will maintain this assumption over a wide range of frequency Knowing the current oscillator frequency it then computes the fundamental quantity of inductance or capacitance that is producing the measured impedance The system then displays this value on the control panel and records it into a library entry during a sweep Analyzer Parameters Oscillato Mad Mater Filter 1 Output Level 1 000 fc V pe ie iter Fist x Precision Frequency 100 289 gt Track Ratio 1 000 Gatin IU C On Frequency Hz 100 289 Meter Filter Filter Functian Flat Track Ratio 1 000 Frequency 100 289 Mete Data Capacitance uF Source Line Output Freq 0 000 Hz Data Curve Graph Name 9 SPL Phase Gate Timin Osc OF 200 0000rn Sec Ose On 50 0000 Meter Di 50 0000 Sec Meter 100 0000m Sec LoFreq Hz HiFreq Hz Points Directio 100 000 1 0001 100 Dn Up Contro Osc OnOff FTU Pulse Gate Time Calculator 343 Misc Applications 344 Z RAA _ E NL A Chapter 16 Capacitor Measurement Range When viewing the capacitor value curves produced from a sw
93. then be run representing the free air curve Next a mass is added to the cone and another sweep taken which is the delta mass curve This is typically clay or some other material that will stick to the cone As asimple guide line the amount of mass added should be in the range of the expected speaker s mass This can be a guess based on the size of the speaker or mass values known for similar size speakers There is no particular value which is necessary but it should be enough to cause a significant change in the resonance frequency and the exact value of the mass must be known Also you must measure the DC resistance of the speaker Revc The frequency range over which the curves are taken should be wide enough to cover the entire driver s impedance changes As a general rule use the 10Hz to 40kHz frequency range with a Precision sweep mode of 300 points It is very important that there is adequate resolution and precision This range will work for any type of driver from woofer to tweeter The Speaker Parameter dialog will make use of the data at both ends of the frequency range It is strongly recommended that the 10Hz to 40kHz range be used when taking these types of impedance curves The 10Hz low end limit is needed for most woofers and the inductive rise at the high end will be used by the Speaker Parameter dialog as well to determine the frequency dependent modeling of the electromagnetic system Generate the Phase The phase
94. typical setup for the LMS Analyzer Parameters for this type of test would be as follows Meter Filter 1 and Meter Filter 2 Filter Type Bandpass Osc Freq Tracking ON FreqRatio 1 000 F O Sweep Control Meter Input Mic Input Data Type SPL Data Mode High Speed or Precision Data Points 30 50 339 Misc Applications 340 Chapter 16 Manual Testing After the physical layout is constructed and the setup for the analyzer param eters tests are performed to establish a standard loudspeaker curve to judge the rest of the production units The oscillator level and frequency set prior to running the sweep must be documented so that the same conditions can be later duplicated for the comparison testing After the standard speaker has been measured use the same LMS analyzer parameters setup with the oscillator set to the same frequency and level established when measuring the production lots Saving this setting to a QuickSet file is very helpful for later recall of the same setup The standard speaker s curve must be located in the currently loaded Curve Library Set the Data Curve position to the next consecutive Curve Library number from where the standard curve is located and run the first sweep on the production speaker Before running the Curve Compare processing operation Max and Min limit curves must first be established To quickly get started these can be produced by simply offsetting the standard curve up an
95. typically to a value of unity In some dialog locations additional constraints may be placed on the numeric value that you enter This is to maintain the validity of the inherent formulas involved with the parameter For example if you were entering one of the values involved with the equation 2 3 5 then some other value in the equation must be simultaneously adjusted to maintain the validity of the equation The program will perform many of these tasks for you automatically Equation checking is performed when the focus leaves the current edit control This informs the program that you have finished editing a value You can Tab to another control or click the mouse in a different control to force the program to check the parameter relationships LMS 4 1 User Manual Chapter 2 General Features 2 8 Color Select Dialog A special button control is located on many dialogs throughout the program which pro Background Eu vides for special editing of color selection Two examples of such buttons are shown here Note Underline EN on the right The center of the button displays the current color for the parameter When you click the button another dialog will open to change the color Standard Calor BETTEN NH Extended Color BREED E Custom Color Selectia Current Color Add Custom Hue 218 2 Made
96. vertical data in the Source Curve entry The transform will write the resulting group delay response to the Left vertical data of the Result Curve entry The curve list boxes provide selection of the library curve for the operations These special list boxes shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Group Delay Transform Parameter Source Curve with Phase Data 13 2kHz BandPass Freq Result Curve for Group Delay 29 Result G13 G12 Freq atin Phase Cancel Help LMS 4 1 User Manual Chapter 7 Processing Menu The first graph below shows the magnitude and phase response of a Highpass filter After the Group Delay Transform is applied to this data the lower graph of group delay is produced Theripples in the response are due to the measurement variations typical of empirical data The group delay transform 1s very much like a derivative and accentuates any variations or instabilities in the phase response m Voltage vs Freq 3d Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K Time vs Freq Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40
97. vertical lines between the zones of each curve entry After this is selected the low high slopes will be automatically calculated and presented in the two editing fields with units of dB Octave The graph below illustrates the asymptotic slope at both the low and high frequency limits For impedance curves the Automatic Tail Correction and Mirroring provides additional special processing The calculated slope values may require adjustment If the magnitude curve contains ripple or noise the slope near the frequency limits may not be stable In these cases you should adjust the values to represent the true asymptotic slopes as the frequency goes to OHz and Infinity Magnitude Response LMS 4 1 User Manual Chapter 7 LMS 4 1 User Manual Processing Menu The asymptotic slope of a Ist order filter function 1s of course 6 02dB Octave If you know the actual Lowpass and Highpass orders of the response represented in the magnitude data you can easily enter the appropriate values as multiples of 6 02 For example in the previous graph the magnitude data was relatively rough and it was known that both the Lowpass and Highpass slopes should be 4th order The slopes were corrected to 424 08 and 24 08 dB Octave The resulting phase and group delay are shown below Phase Response 119 Processing Menu Chapter 7 To demonstrate the accurac
98. would be required for dB V or dBm For dB units the dB Ref value then defines whether it is dBV 1 000V or dBm 0 775V Note Please pay close attention to whether you have linear or log axis data Library Curve The data that is obtained from the capture process will be written to a Library Curve entry The entry is selected from one of the 50 possible choices in this list box The default name given to the entry will be Capture Filename and the curve will be enabled for display Scan Direction The curve scanning process can be performed from either the Top Down or from the Bottom Up This can be significant if there are other colors on the image similar to that of the curves Scanning from either direction may avoid picking up other similar colored pixels above or below the curve 177 Utilities Menu 178 Chapter 8 Color Match The slider controls a tolerance matching value in for pixel colors scanned in the image The current value is displayed above If the value is zero then pixels will only be selected as part of the curve if their color matches the exact Curve Color selection described above A higher tolerance value will allow more latitude in pixel matching The Preview button will run the curve scanning process and draw a sample curve on top of the image This shows you how the pixel curve colors will be mapped The Clear button will erase the preview curve The small color button allows you to change the color u
99. 00 1K 2K 5K 10K 20K 40K 158 LMS 4 1 User Manual Chapter 7 Processing Menu An example of a Relative Reference test is Shown below The test curve is shown in Blue and the reference curve is shown in Red The reference curve was produced using the Unary Smooth operation If the comparison is conducted with a tolerance of 0 25dB or higher the test passes At around 5kHz the 0 25dB worst case deviation occurs with the reference curve This method is useful when you wish to compare single curve measurements with an ideal reference curve Curve Compare Metho Test Parameter C Absolute Lo Freg Hz 10 0000 Hi Freg 10 0000K 14 5 Freq SPL Phase Relative Absolut Limit Curve 18 Max Limit Freq SPL Phase Min Limit Curve 16 Min Limit SPL Phase Relativ Tolerance dB 0 2500 t Reference Curve Relative Flatness Reference Curve 17 Bcalarhms Smoothed Freq SPL Phase Cancel Help SPL vs Freq 2 3 5 7 ins um 49 725 LMS 4 1 159 User Manual Processing Menu Chapter 7 An example of a Relative Flatness testis shown below The test curve is shown in Blue There are no other curves required The Relative Flatness method computes it s own mean value by averaging
100. 105 10 G nano 10 n M If additional numeric values fol low E then it 1s treated as scientific we w v Co ee T format peta 10 femto 10 f pw w S fe ee 353 Appendix 354 LMS 4 1 User Manual Appendix LMS 4 1 355 User Manual Appendix 356 LMS 4 1 User Manual LMS 4 1 User Manual Index Symbols 2 Wire and 4 Wire 41 A About Box liv About Modules 247 About Program 249 Absolute 157 Absolute Relative 18 accelerator key 47 Acoustic Ref 196 Acoustical Summations adapter cable 41 Adobe Illustrator 169 Adobe Type Manager 3 Adobe 1 3 AI 169 airload 139 alligator clips 41 Analyzer Parameters 79 Analyzer Block Diagram 30 Analyzer Configuration 63 Analyzer Control Panel 33 Analyzer Parameters 33 anechoic chamber 279 297 Anechoic Chamber Measurements 280 arithmetic operations 115 artwork 67 ASCII columns 163 ASCII text listing 143 asymptotic slope 119 asymptotic slopes 145 3 28 audio amplifier 35 Auto Color 61 Automatic Curve Info Notes 75 Index Automatic Labels 61 207 Automatic Tail Correction 118 AutoRun 254 AutoRun a Macro 254 Axis 21l B Background color 67 Backup Library Files 61 BAK 61 Bandpass 81 Bandreject 81 Baud Rate 96 Beep At End of Sweep 61 Binary Math Operations 115 BL 137 blinking rate 61 block diagram 30 blocked electrodynamic speaker BMP 168 Border Line 67 boundaries 279 burst of sinewaves 82
101. 15 2 Impedance by Constant Current The method used for direct impedance measurements by LMS is called constant current This is because the source impedance is high 5000 so that the current following through the voice coil remains relatively constant The previous graph shows the cable impedance measurement Also the phase transform was run on this entry to produce the phase response This is accomplished by simply shorting the clips together that will be connected to the speaker As shown LMS even measures the high frequency rise of the cable inductance At the mid and low frequencies the cable shows about 0 6 Ohms Now the clips are hooked to the speaker and another sweep taken This is actually the impedance of the cable plus the speaker We can then use the SUB process to subtract the shorted cable curve from this curve leaving the true speaker s impedance without the cable The graph below shows the SUB result curve which is the true speaker impedance and the cable plus speaker impedance As the curves show there is a noticeable difference between the two when the impedance magnitude 15 at the low portions b b e A Lb rr 8 _ ABB Ls T sss Lo ds rep ws pp M INTE I E S 11 ENT ER EN PES LL o dp RCE OM no EXE H o R 3 CN E UE CT LMS 4 1 User
102. 181 graphics applications 167 Grid Parameters 67 ground plane 279 Ground Plane Measurements 281 group delay 117 Group Delay Transform 124 GRPHCURVE 263 GRPHSCRN 263 guidelines 181 359 Index 360 H half space 279 Half Space Measurements 282 halftones 56 Help About Modules 247 Help About Program 249 Help Contents 241 Help I Glossary 245 Help Index 243 Hide All 70 Highpass 81 HiSpeed 80 Horizontal Angle Scale 210 horizontal data points 151 Horizontal Frequency Scale 208 Horizontal Left Vertical and Right Vertical PG Data 164 Horizontal Scales 207 horizontal scales 44 Horizontal Time Scale 209 Hot Keys 274 Hot Spots 20 HSV 26 I O port 100 IEC baffles 137 IF 263 IFCRKEYGOTO 263 IFSBKEYGOTO 263 Imag sin 114 Impedance 84 Impedance by Constant Current 308 Impedance by Constant Voltage 310 Impedance Measurement 41 Import Curve Data File 163 Impulse response 129 INC 203 Inductance 85 inductance 91 Inductor Range 347 Infinite Baffle 137 ink jet 56 INPUT 264 INTCAL 264 Internal calibration 100 Internet liv interpolation 151 Inverse Fast Fourier Transform 126 inverted 109 ISA bus slot 3 J 168 K KeyWord 256 keywords 259 Krm 132 Kxm 132 L Labeling of the scales 207 Labels 212 landscape orientation 55 laser 56 last library 48 LEAP 131 141 Left vertical 147 LEVEL 264 LIBLIST 264 limit curves 158 line attributes 72 Line Output XLR 307 LMS
103. 20 INPUT Enter Menu Selection Number 1 3 x Work Are Test Program for Macro Development Selection Menu ilj BRun Sweep Test Sweeps 4 Print Graph 3 Levwel Curve 4 Compare Curves 5 Name Curve 6 Ratio 15 16 18 i Delta 15 16 18 8 Graph Display 91 Program Command Lin Enter Menu Selection Number 1 3 Parameter Sn ten LMS 4 1 251 User Manual Macro Programs Chapter 13 252 LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs 13 1 Macro Programming The LMS system software contains a capability known as Macro Programming This feature allows the user to write programs or scripts that contain LMS macro commands that perform a variety of tests and system software operations Using macros the LMS system will perform a set of prescribed tests and or menu operations automatically as the program is executed Writing macro programs is structurally very similar to that of programming in BASIC The program can be created and written using any of the usual types of text editor programs or word processing programs However the LMS software contains a built in Utilities Macro Editor which is ideally suited to this task The LMS macro language is straightforward and provides many additional features which help the operator during program execution and allow program functions to be modified and controlled during run time These include writing cust
104. 43 66E 666 6 68643 66E 666 6 68643 66E 666 6 68643 66E 666 6 68643 606E 666 6 68643 66E 666 6 68643 66E 666 6 68643 66E 666 6 68643 606E 666 6 68643 66E 666 6 68643 66E 666 6 68643 66E 666 6 68643 66E 666 6 8643 66E 666 6 68643 66E 666 4 7942 88H 4 7942 88H H 8743 06E 88H 54 954458HE 5 B 03788B8E 5 12128B8E 000 5 2808BBBE 5 29049BHB8E 888 5 38568HBE 88H 5 4 763 86E 88H b5 571888E 5 65658BBE 888 5 765BB8BE 5 86528HE 888 5 0682B8HE 88H 6 80 238B8E 88H 6 1817 BBE 88H 6 291188E 88H 6 B66BBE 668 6 52218B8E 88H 2 52 am Utilities Menu Chapter 8 Notepad TEST TAT _ OF gt lt File Edit Search Help LHS TH 4 0 0 147 Apr 23 2088 C opyright 1993 2688 by Lineark Systems Inc LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu 8 3 Export Graphics to File Utilities __ ES Import Curve Data File Export Curve Data File E alii Export Graphics to File Export Graphics to Clipboard CuweCanue The Utilities Export Graphics to File menu item will open a dialog which produces graphical export of the artwork from the graph window in the program The tool button as shown above on the Utilities toolbar can also be used to activate this item Curve Capture Curve Editor Macro Editor MOF E ditor T
105. 5 dBm Different tab units have different dB reference choices 211 Scale Menu 212 Chapter 9 Divisions When the axis is Linear or dB the Major Div and Minor Div values will be enabled For Log axis only the minor divisions are relevant Units Using the Prefix you can produce units of mVolts uVolts nVolts etc This is only enabled when either Linear or Log axis is chosen When a dB axis is in use this is disabled The units field displays the total combined unit label for the scale Labels A data grid is displayed along with three buttons Make Clear Sort Once you have defined the other parameter values clicking Make will generate a suitable list of labels for the scale The generated labels are then listed in the data grid The generated labels are placed at the major divisions of the vertical grid lines If you wish to delete the entire label list click the Clear button Single labels can be deleted simply by erasing the text in the desired entry Additional labels can be added using the empty locations further down the list Clicking the Sort button will sort the list based on the time value represented in the label text Note The labeling controls will be disabled if the Automatic Labels option is enabled in File Preferences LMS 4 1 User Manual Chapter 9 LMS 4 1 User Manual Scale Menu 9 2 Auto The Scale Auto menu item provides automatic adjustment of the vertical scale in the
106. 61 Index 362 NT4 3 NT5 3 number of divisions 44 number real format 353 Numeric Entry amp Formats 23 Nyquist 208 O OKBEEP 266 on line help ONFAILGOTO 266 Open 48 optimization 131 OSC On Off 90 OSC output On Off 33 Oscillator Panel 80 OSR2 3 out of phase 301 Output Level 80 P PAC Interface 95 PACA 3 pan 22 PASS FAIL 157 Pass Fail SPL measurements 339 Passive Network 323 paths 49 PAUSE 266 PCX 168 PDF 3 169 PHASE 266 phase 70 Phase Offset 107 108 Phase Offset 105 Phase Transform 117 pit measurements 282 pixel ratio 176 Planning A Macro Program 258 PNG 168 point Floating numbers 353 Polar Conversion 201 Polar Convertor 199 polar plots 210 Polar SPL 85 Polarity 211 Popup Menus 20 Portable Analyzer Chassis 95 portable analyzer chassis 3 Portable Document Format 169 portrait printing 55 PostScript 3 167 power amplifier 310 Precision 80 Preferences 60 Prefix 212 pressure field 280 PRINT 266 Print 55 PRINTCN 266 Printer Configuration 55 printer setup 55 PRINTFN 267 PRINTVN 267 PRNPORT 267 Program Structure and Syntax 256 program window 229 Progress Meter 19 project folder 50 PULSE 267 Q Q values 135 Qes 135 Qms 135 Qts 135 LMS 4 1 User Manual LMS 4 1 User Manual quadratic 151 Quality Control Pass Fail Testing 339 quasi anechoic measurements 288 quasi distortion measurements 81 Question 186 Quick View 21 QuickSet Files 34 R
107. 8980 folder with a file name such as SN123456 MDF The Author Linear Systems Inc serial number of your file will of course be different Date Jun 23 2000 Fri 12 35 am Data Points 300 Ok Cancel Help Lo Freg Hz Hi Freq Hz 100000 400000 A summary of the data will appear in the fields of the dialog Click Ok to save your changes LMS 4 1 User Manual Chapter 6 Analyzer Menu 6 6 PAC Interface Analyzer Analyzer x Parameters 5 Start Stop ES Pu B F10 1 ES gi RLC Meter Microphone Setup The Analyzer PAC Interface menu item will open a dialog which controls the setup and linking of the Portable Analyzer Chassis PAC unit The tool button as shown above can also be used to activate this item PAL Interface Macro Run Calibration The PAC interface allows you to setup and establish the communications link between the LMS software and an LMS analyzer card located in the PAC unit The PAC unit communicates over a serial port with your computer which eliminates the requirement of mounting the analyzer card in your computer General Operating Instructions and Setup The first step 1s to mount the LMS analyzer card into the PAC unit With the PAC power OFF remove the screws on the cover of the unit and remove the cover Mount the LMS analyzer card into one of the three or four slots Replace the PAC cover and then fasten again with the screws
108. Atel set a wrub set 3 Rub set 2 Z 1 set File name Splset Files of type Set Files set Cancel LMS 4 1 User Manual Chapter 3 Getting Started 3 3 An SPL Measurement In order to make a simple SPL measurement of a loudspeaker with the LMS analyzer you will need the following A loudspeaker to measure The LMS installation completed An audio amplifier SIR If your amplifier does not have XLR inputs you will need to make an adapter FEMALE MALE cable consisting of a female XLR and the appropriate plug on the other end for 1 s your amplifier like the RCA connector shown here Since the LMS oscillator output cable is unbalanced you can connect the adapter cable to Pin 2 and or ground to Pin 3 of a female XLR Place the loudspeaker and microphone as desired Since this is not going to be a gated measurement the choice of placement will determine the results If you have an extension cable and can locate the speaker outdoors a ground plane measure ment is the quickest to setup Simply place the speaker on its side on the ground preferable on concrete or asphalt and place the microphone also on the ground about 1 meter on axis in front of the speaker If you choose to make the measurement indoors you will also be including the room reflections Analyzer Parameters EH EI Plug in the LMS microphone to the Oscillato Mod Meter Filter 1 LMS microphone input cable black Output Le
109. COMLCLR first Example 100 COMLMSG This is a command line message COMPARE Testnum Maxnum Minnum Compares a curve The COMPARE keyword is used to compare a curve between two other curves used as limits and gives a PASS FAIL response on the screen This is an Absolute Comparison The parameters are entry numbers in the curve library and must be integers 1 through 50 The first parameter is the number of the curve to be compared or tested The second and third parameters are the maximum and minimum limit curves If the test curve is between the two limit curves a PASS response will be given If the test curve exceeds either the max or min limits a FAIL message will be given Example 100 COMPARE 11 12 13 COPYCURVE entrynumFrom entrynumTo Copy Curve The COPYCURVE keyword is used to copy a curve to another entry position in the library This produces a duplicate The first entry number parameter is the curve to be copied and the second entry number is the location of the copy Both parameters must be integer numbers 1 through 50 Example 100 COPYCURVE 11 13 CURVEUNITS entrynum LeftUnitName RightUnitName set the type of vertical data units The CURVEUNITS keyword is used to change the type of vertical units of a curve Unit names are Freq Time Phase SPL Volt Amp Imp Ratio Ind Cap Excur Veloc Accel The curve entry number parameter must be 1 50 Example 100 CURVEUNITS 11 Imp Phase DATACURVE entrynumber Se
110. Curve Capture The Utilities Polar Convertor menu item will open es y dialog for compiling a group of frequency curves into acra MDF Editar polar curves The tool button as shown above on the Utilities toolbar can also be used to activate this item This utility is very useful for manually constructing polar plot data from a group of normal frequency response measurements Each frequency response curve is taken at a different location radially around the transducer Using this dialog the representative locations of each curve are entered and then an output list of curves is established with specific frequencies for which the polar curves will be generated Since there are a maximum of 50 curve entries in a library the total number of input and output curves must fit within a single library Typically there are many more input curves than output curves The process can be repeated while changing the output polar frequencies saving multiple libraries thereby producing a larger number of output polar curves Polar Convertor Library Curve Mat Used 0 0000 161995 10 2 40 08 SPL Hot Used 0 0000 161586 10 2 40 08 SPL Hot Used 0 0000 161557 10 2 40 08 SPL Hot Used 0 0000 161588 10 2 40 08 SPL Hot Used 0 0000 161999 10 2 40 08 SPL Mat Used 0 0000 161990 10 2 40 08 SPL Mat Used 0 0000 161991 10 2 40 08 SPL Mat Used 0 0000 161992 10 2 40 08 SPL Mat Used 0 0000 161995 10 2 40 08 SPL
111. Delay Settle Reads Sec 00400 ATED Test Delta dB 20 0000 Debounce Time Gain Sec 1 0000 Gate Cutoff Freg Mult 1 0000 Debounce Time 100H2 Sec 1 0000 AutoRng Hi Limit Mult 1 1000 Debounce Time 1kHz Sec 1 0000 AutoRng Lo Limit Mult 0 0330 Debounce Time 10kH2 0 5000 Cancel Help 63 File Menu 64 Chapter 4 4 12 Exit The File Exit menu item is used to terminate the us n program The accelerator key CTRL Q can be used to activate this item using the keyboard as well Reopen Etits Gaves Revert When this option is selected the system checks to see if any changes have been made since the library was last saved If changes have been made then a dialog box will appear with three options for exiting the program Load QuickSet File Save Duick Set File Print Ctrl P que If the current library name is Untitled you will always Preferences receive this message Use the YES button if you wish to save the library and another dialog box will appear to allow you to enter a new file name if the current name is Untitled If the current name is valid the file will be updated The program will exit after saving the file Use the NO button if you do not wish to save the current library as a file or do not wish to update the existing file on disk The program will exit after pressing this button Use the CANCEL button if you wish to abort the exiting pr
112. Gain Ratio 0 957 Ratio PASSED Gate Freq Ratio 1 003 Fatio PASSED Offset Test 0 999 Ratio PASSED Freq ffzet 0 592 Index PASSED Freg cale z 526 Index PASSED Fremq ffzet 1 180 Index PASSED Freg cale 5 449 Index PASSED Freq ffzet 2 342 Index PASSED 100 LMS 4 1 User Manual Chapter 6 Analyzer Calibration Jippe Farameter Under Tes TEE Full Scale Output Voltage rme fe External Enter LineOut Click Ok when done Abort a 25 External Calibration LHS port UZIlF Analyzer Menu External calibration is a test which is completed for your LMS card at the factory prior to being shipped While it is generally not necessary to perform this calibration more than once it should be run at least initially This will allow you to set the absolute voltage levels You will be prompted to measure the output voltage by connecting a voltmeter to the OSC Line Output Note If you do not have a suitable meter just enter 5 20 on the command line when asked and continue with the procedure The test frequency is 60Hz The meter should have an input impedance of gt 100k Ohm for best accuracy Cables should be connected to Pin 2 and Pin 3 of gray cable male XLR Set the voltmeter for reading an AC voltage of 5 Volts If you do not have a meter ignore this request and click Ok Next you will be prompted to connect the various cables together so the analyzer can perform loopbac
113. Graph Analyzer Processing Utilities Scale View ToolBars Help P25 at 1M C13 at 1M D25 at 1M GP ATI Parking Lot 11 15 52 2 83 v at m 4 0 0 224 Person Project Jun 13 2000 Jun 11 2000 Company File Sample lib Tue 3 28 am zl 100 Abs Rel 1 P25 at 1M Sif 19081 Hz 76 522dBSPL Let LMS 4 1 15 User Manual General Features Chapter 2 16 LMS 4 1 User Manual Chapter 2 Toolbars LMS 4 1 User Manual General Features 2 1 Tool Bars Tool Buttons amp Control Bars There are 9 menus in the program and over 60 tool buttons arranged on 7 moveable Toolbars Essentially the functions given ona particular menu column are provided as tool buttons on a single corresponding toolbar There is also a status bar shown at the bottom of the screen which provides cursor readouts and other associated functions A progress meter and message display are also contained here There are two 2 control bars also known as trays shown on the main screen These trays autosize to hold the toolbars and have user selectable backgrounds like the Marble pattern shown below One tray is fixed at the top of the screen below the menu and the other tray is known as the ToolBox and is a floating window Toolbars can be moved and r
114. Help LHS Data File C opyright 1993 2668 by LinearX Systems Inc Uersion 4 8 8 198 FileType SET Date Hay 23 2000 Time Tue 2 56 am Aanalyzerset DataCurue 2 DataPoints 200 GateCalcSrcTime 2 65 GateCalcRefTime n 3889m UnitsGateCalcSrcTime 3 UnitsGateCalcRefTime 3 GateOscOnTime 28 888m GateOscOffTime 28 888m GateHtrOnTime 18 888m GateHtrDlyTime 5 B8888m UnitsGate sc nTime UnitsGate sc fFFTime UnitsGateHtr nTime UnitsGateHtrDlyTime FilteriType Filter1Track True Filter1Ratio 1 0000 FilteriFreg 1 0058E Filter Type Filter Track True Filter Ratio 1 0000 Filter Freg 1 0058E OscLevel 4 3460 File Menu The image above shows a text file opened with the NOTEPAD editor 59 File Menu Chapter 4 4 11 Preferences File The File Preferences menu item opens a dialog that us n contains additional parameter settings for the program Reopen These are parameters which are changed on a less frequent basis or provide optional behavior Etits Gaves Revert Preference parameters are stored in the LMS INI file as global characteristics and are not loaded or stored in library files Load QuickSet File Save Duick Set File Print Ctrl P Editor Preferences Cri Editor Path This is the path to the editor you wish to use when opening text files for viewing or editing inside the program The default choice is the Wind
115. IS Ls Ls EX 4 Scalar AMS Vector Ave C Vector AMS of the operation This special list box shows the type of data contained in each 180 deg noana SPL Phase curve Any curve which is currently 15 deg 30 deg 45 deg 60 deg 75 deg 90 deg ene being displayed on the graph is denoted 10 2 40 0KHz SPL Phase 18240 DKHz SPL Phase by Red vertical lines between the zones 10 2 40 0 2 SPL Phase of each curve entry 10 2 40 0 2 SPL Phase 10 2 40 0KHz SPL Phase 105 deg JD2400KHz SPL Phase Note The result curve entry can be the d AT 40 Abit rri ri s same as one of the data curves used to Result Curve 14 Freg Imp Phase All Off All Unity construct the average However the Cancel Hep original data will be overwritten when LMS 4 1 User Manual the operation is completed 153 Processing Menu 154 Chapter 7 The following is an exact description of each of the averaging methods Scalar AVE This is a simple weighted arithmetic average of the magnitude data for each of the curves The phase is ignored in the averaging W ZW Se AW Z We lvl Scalar RMS This is an RMS weighted average of the magnitude data for each curve The phase is ignored in the averaging W ZW Sus AW e X Welv21 Vector AVE This is a weighted average performed using vector mathematics in the complex plane with the magnitude and phase at each dat
116. K LMS 4 1 125 User Manual Processing Menu Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Chapter 7 7 6 Inverse Fast Fourier Transform P E E ES AMM DAB AE ES amp The Processing Inverse Fast Fourier Transform menu item will open a dialog which performs an Inverse FFT on a frequency domain library curve The tool button as shown above on the Processing toolbar can also be used to activate this item Data Transfer Data Splice Data Realan An Inverse FFT transforms a frequency domain response into a time domain Impulse response This dialog also provides convolution to automatically yield a Step response as well Curve Averaging Curve Compare Prior to performing the Inverse FFT the frequency domain source curve must be converted into a specific number of linear frequency data points This process is fully automatic and the user only needs to specify how many linear frequency data points are to be used The list box at the top provides a list of available choices The frequency domain entry to be transformed is specified in the Source Curve list box The resulting time domain Impulse and Step response entries are selected in the following two list boxes The curve list boxes provide selection of the library curve for the opera
117. MS MDF folder Select the Analyzer Microphone Setup menu item as shown below The first tab Mic Input shows the setup information which is initially blank An MDF file can be loaded into both the Mic or Line inputs but in most cases the Line input is left blank We are only interested in setup here for the Mic Input Click the Load MDF button and then select your MDF file in the Open MDF File dialog You will need to change into the MDF folder The SN of your file will be different After the MDF file is selected the data will appear in the dialog tab panel as shown below Click OK to save these changes permanently Microphone Setup Mic Input Line Input ix Parameters rl Sweep Start Stop Osc On Off F10 Meter Microphone Setup Interface Macro Editing 10 Macro Aun Calibration Open MDF file Look in Mdf Filename 5180001 Files of type MDF ASCII Files Cancel LMS 4 1 User Manual Microphone Setup x MOF Dat Model Acoustic Ref 00000 SFL Serial Electric Ref 00000 BHO Date Data Points Lo Freg Hz Hi Freq Hz 0 0 0000 0 0000 Cancel Help Mic Input Line Input MDF Dat Model CES Acoustic Ref 94 0000 epu Serial ETS Electric Ref 556600 Author Linear Systema Ine 0000000 Date May22 1998 Fn1231AM ko o Data Points Lo Freg Hz Hi Freq Hz 552 10
118. MS output level controls in the analyzer parameters dialog Before starting the measurement sweep we will create a new curve library Select the File New menu item This will clear all library curve entries title block data and any notes The library will be given the name Untitled Lib To see what the Curve Library now looks like select the Graph Curve Library menu item This can also be activated by using the shortcut key F6 or the tool button with the wavy lines The Curve Library dialog is shown below 2 LMS Untitled_lib File Analyzer Processing Utilities Scale ESSI amp EN Curve Library There are 50 curve entries in a given library These entries can hold many different types of data possibly taken over a variety of different frequency ranges The Curve Library also shows which curves are selected for display on the graph as indicated by a check in the second G column A single curve is always selected as the location where the next sweep data will be placed This is called the data curve entry It is indicated by the angle brackets in the first column and is also provided in the edit box Data Curve Farameter Data Showall Hideall Delete Delete All Copy Curve Paste C mile 24 a ert Curve Pees Right Lighter Right Phase eee as width SPL Phase 0 20 2 i SPL Phase 0 Solid 2 3 Ll No SPL Phase 0 Solid 20 98 4 No
119. Moving the analyzer to the PAC unit is equivalent to moving the analyzer to a different computer where the bus clocks may not be the same Serial Port This group box contains buttons for selecting the serial port to which the PAC unit is connected This group box is only enabled when the PAC link is NOT active The selection cannot be changed while the link is active and can only be changed when the link is OFF Note If you choose a wrong COM port where another device such as the mouse is already connected when you press the Start Link button the mouse may malfunction requiring a reboot to restore mouse operation Baud Rate This group box contains buttons for selecting the speed of communication over the serial port to the PAC unit This group box is only enabled when the PAC link is NOT active The selection cannot be changed while the link is active and can only be changed when the link is OFF The PAC unit has a built in feature of AutoBaud detection and will automatically lock on to the baud rate chosen here No jumper or switch changes in the PAC unit are required It is best to always use the highest baud rate of 57 600 unless other circum stances do not permit this Generally the only problem with using high baud rates occurs when long cables are used between the computer and PAC unit For typical applications where the serial port cable is 1Oft or less using 57 600 should be no problem If longer cables are needed and errors o
120. NUSCRN RollDn MacroRun Dialog MICMAKE 1 Generate a MIC cal file MUL MUL curves A B NAMECURVE Enter the name for a curve OKBEEP OK Beep Sound ONFAILGOTO If Compare test Fails goes to Line Number PAUSE Wait for Key Press PHASE gt Generate Minimum Phase Response PRNPORT 4 Selects the port for the PRINTSTR command PRINT PRINTCN PRINTFN PRINTVN 4 Print a graph PRINTSTR 2 Send a string to the PRNPORT PULSE Pulse the TTL output REALIMAG Seperates the Real and Imaginary curve values RELCOMPARE Relative Curve Compare SAVELIB Saves Curve Library to Disk SCALE Scale a curve adjust the magnitude SETSCP Change the value of an SystemControlParam SETVAR Set the value of an integer variable SMOOTH Smooths a curve Same as LEVEL SORT SORT of curve A SUB 2 SUB curves A B Same as DELTA SWEEP Run a sweep RATIO RATIO curves A B Same as DIV VARLABEL Declares variable labels WAIT Wait time in Seconds WORKCLR s Work Area Clear WORKMSG Work Area Message ZCURVEFO Test a speaker Z curve for Fo ZCURVEZO Test a speaker Z curve for Zo Hot Keys ESC 1 End macro program and return to LMS CTRL End End macro program and return to LMS CTRL D End macro program and return to LMS This completes the summary listing of Macro Keyword Commands Be sure to check t
121. Sample font size e This program only utilizes vector fonts This means that TrueType and or Adobe ATM fonts should be present If you will be printing to a pen plotter you should choose a plotter stroke font such as Modern that does not require fill and can be easily drawn by a pen LMS 4 1 User Manual Chapter 2 LMS 4 1 User Manual General Features TypeFace In this panel the number of vector font families is shown the type of font which 15 currently selected and a list of the available fonts TypeSize The size of the font in points can be selected from the list box incremented using the spin buttons or entered directly in the list box TypeStyle Several check boxes are provided to control the style of the font All or none of the options can be combined TypeColor This button displays and selects the color for the font To change the color click the button and the Color Select dialog will be presented Sample Text A text sample of the current selection is displayed in this panel The background color will be automatically set depending on the color of the font A check box allows you to view the font in actual size or at a different size controllable by the spin buttons at the lower right of the panel 29 General Features Chapter 2 2 10 Analyzer Block Diagram The figure below shows the equivalent block diagram for the LMS analyzer The analyzer is a digitally controlled analog system
122. Scrolling 188 E Editor 58 Editor Path 60 Electric Ref 196 electrical and mechanical parameters 137 electromechanical 131 Email liv 249 LMS 4 1 User Manual LMS 4 1 User Manual 167 EncapPostScript 169 END 261 engineering 353 engineering format 24 engineering notation 23 Enhanced Metafile 169 Entering Numerical Values 24 environment 279 environmental reflections 279 EPS 167 EQ curve 337 ERBEEP 261 Erm 132 EXE 247 Exit 64 EXITTODOS 261 Exm 132 Exponentiation 105 109 EXPORT 262 Export Curve Data File 165 Export Graphics to Clipboard 173 Export Graphics to File 167 EXPORTCN 262 262 EXPORTVN 262 EXTCAL 262 External calibration 101 external microphone 195 F fan out 41 far field measurements 283 Fast Fourier Transform 128 favorite editor 60 Fax File Editor 58 File Exit 64 Index File Preferences 60 Floating point numbers 24 floating window 237 floating windows 231 flowchart 258 Font Parameters 67 Font Select Dialog 28 Fonts 3 format engineering 353 format scientific 353 Frame Parameters 67 Free Air 137 Frequency 80 frequency domain 126 frequency magnitude and phase 164 Frequency Translation 105 111 G Gate Time Calculator 83 gated measurements 149 Gated SPL Measurements 288 Gating 80 Generate the Phase 316 GIF 169 global or library specific 62 GOTO 263 Graph Parameters 67 graph designs 67 graphical editing
123. Woofer Mid the tweeter s response is now added or subtracted as well The correct response in this case was produced by ADbDing the tweeter curve into the WOOF MID previous result curve The tweeter needs to be summed in phase 100 90 80 70 60 50 30 A Woofer Mid Woofer Mid 301 SPL Applications 302 Chapter 14 The final result is shown in the graph below along with the original measured system response The phase curve shown is for the summation response The match is very good with the notable exception at 2200Hz of a sharp edge The reason for this was a severe cone break up problem in the 6 5 inch midrange driver The cone break up was more severe when only the midrange unit was active When both the midrange and tweeter are connected the cone break up from the midrange improved This is probably due to some mutual coupling effects between the two drivers It should also be mentioned that the phase response produced in the final result curve from the summation of the individual ranges includes the non minimum phase components caused by the summation of multiple ranges through a crossover SPL vs Freq 100 90 70 60 50 40 30 Computed Response vs Measured Response LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications The graph here shows the phase response produce
124. a Frequency Time Angle Axl Hang Division C Linear Max 40 DOCOK Major fo i L 94 Min 10 0000 Minor 2 Pla tv Hect Unit Polar Prefix El i EE peur 44 The powerful scaling system provides the ability to show data curves in al most any manner desired Both rectan gular and circular plots are fully sup ported The labeling system runs fully auto matic and produces excellent labels for most applications If you have some special need for custom labels you can disable the automatic mode from the File Preferences dialog However in this case you will then be responsible for manually regenerating labels as needed whenever the scales are changed LMS 4 1 User Manual Chapter 4 LMS 4 1 User Manual File Menu File Menu I Ctri 0 F Save Ctrl 5 Saves Revert Load QuickSet File Save QuickSet File Print Ctrl F Editor Preferences Ctrl Q File B g GE E SGIBSge 45 File Menu 46 Chapter 4 LMS 4 1 User Manual Chapter 4 File Menu 4 1 New EI ae Ctrl 0 Pe BH e gj Reopen k cuf Sp The File New menu item starts a new library The aves ko Revert accelerator key CTRL N can be used to activate this item Load QuickSet File using the keyboard or the tool button as shown above Save Duick Set File Print Ctrl P If your existing library has changes
125. a point The phase is used in this method W ZW Vip I We Vector RMS This is 5 average performed using vector mathematics in the complex plane with the magnitude and phase at each data point The phase is used in this method W LW Vous X We v2 LMS 4 1 User Manual Chapter 7 Processing Menu The top graph shows an example of 12 SPL curves representing the response of a speaker at different angles of rotation The bottom graph shows the resulting Scalar RMS average of these curves SPL vs Freq dBSPL 2 10 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K SPL vs Freq dBSPL 2 1715 20 50 100 200 500 1K 2K 5K 10K 20K 40K LMS 4 1 155 User Manual Processing Menu Chapter 7 156 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Processing Menu 7 14 Curve Compare P E E ES AMHR DAB AE DS The Processing Curve Compare menu item will open a dialog which pe
126. a represented in the curve For example you may wish to change a voltage measurement which actually represented current through a shunt to Amps The type of units defined here determine which scale set will be used when drawing the curve on the graph The Points column displays the number of data points in the curve The maximum number of data points in a curve entry is 4096 The Style Width and Color columns determine the line attributes used to draw each curve The width parameter is given in mils 1 1000 of an Inch If the Same Line Type check box is enabled all curves will have the same style width and color If the Right Lighter check box is enabled the right side curve generally phase will be drawn with a lighter shade of the specified color Note Win9X does not support drawing complex lines larger than I pixel width This means dash dot etc WinNT is required to support these styles T2 LMS 4 1 User Manual Chapter 5 LMS 4 1 User Manual Graph Menu Curve Info Dialog When an ellipse button in the nfo column is clicked the Curve Info dialog will appear as shown below This dialog allows you to enter edit additional notes for each curve entry The Transfer options panel provides some handy features for displaying the curve info text on the graph page If the Auto Copy 1s enabled then the first two enabled curves will have their notes automatically transferred to the graph note area This isadynamic process which oc
127. a tedious job to say the least but in fact it is really very easy The Utilities Curve Editor is ideally suited to vector line drawing of a response curve The Utilities Curve Capture provides a means to distill vector curve data out of raster images These can be scans of printed graphs pen plotters etc Another way to create curves is by using asimple text editor or spread sheet program to manually create an ASCII text data file The Utilities Import Curve Data File can then be used to import the data file The graph below illustrates the need for creating two max min test limit curves for a curve comparison Any of the above methods could be used to construct the limit curves On the following page the Curve Editor is shown pereforming such a task SPL vs Freq 10 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 331 Misc Applications Chapter 16 2 LMS 3wayspl2 lib File Graph Analyzer Processing Utilities Scale View ToolBars Help Curve Editor Left Vertical SPL Control Graph Node Show Snap View Help NA SAN F 1 i ii ii Wi Mil Curve C13 Partioned Freq Imp Phase Points 500 Read Write 369 0280 Hz 88 3938 dBSPL 2 The Cur
128. able labels The VARLABEL keyword is used to declare the variable labels that will be used in your macro All variables must be declared before any operations can be performed on them The labels are delimited by a SPACE character There 15 a maximum of 20 variables and the number of characters in the labels of all variables combined must not exceed 80 The labels can be made up of any alpha numeric combination Only one VARLABEL command is allowed per macro program All variables must be defined with a single VARLABEL command Example 100 VARLABEL A X IAB FLAGI WAIT seconds Wait time in seconds The WAIT keyword is used to cause the system to wait before executing the next statement line This could be used to allow the operator to view a message or to do something before the next command The seconds parameter can be a decimal number or an integer This example causes a wait for 5 and a half seconds Example 100 WAIT 5 5 LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs WORKCLR Work Area Clear The WORKCLR keyword is used to clear the work area in the MacroRun dialog If other messages orinformation are no longer desired in the work area then use this command to erase it Example 100 WORKCLR WORKMSG message Work Area Message The WORKMSG keyword is used to write a message in the work area of the MacroRun dialog This could be used to tell the operator something to do or to notify the
129. al Chapter 15 Impedance Applications Impedance Applications 15 Impedance vs Freq De 200 180 150 120 100 90 80 90 70 60 60 50 30 40 30 E 30 20 60 90 10 1 1 9 120 8 7 150 3l 180 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K LMS 4 1 User Manual 305 Impedance Applications Chapter 15 306 LMS 4 1 User Manual Chapter 15 LMS 4 1 User Manual Impedance Applications 15 1 Measuring Methods for Impedance Making impedance measurements with LMS requires a minimum of setup Simply connect the speaker to the oscillator Line Output XLR load the Zimp2Wire or Zimp4Wire QuickSet files and run a sweep With the 500 Ohm output impedance of the LMS oscillator the load is placed into an equivalent voltage divider The LMS software solves this voltage divider for the true load impedance of the speaker automatically removing the effects of the LMS output impedance This type of impedance measurement method is called constant current since the driving impedance is relatively high To enhance the accuracy of the measurement the shorted cable impedance can be measured first and then subtracted from the speaker cable curve using the LMS Processing Binary Math Operations SUB process Impedance vs Fre 307 Impedance Applications 308 Chapter 15
130. alyzer Menu 80 Chapter 6 Oscillator Panel The Output Level edit box is used to set the output level from the sine wave oscillator This edit box also contains a spin button which can be used to adjust the level up or down by about 3 The maximum output level is around 5Vrms A units button directly follows the edit box and can be used to toggle through different units for the output level including Volts dBV and dBm The Frequency edit box operates in much the same way The low frequency limit is 10Hz and the upper frequency limit is 100kHz This frequency is the static frequency when the system 15 not performing a sweep The spin buttons will change the frequency by about 1 increments A units button is also provided The frequency can be swept manually by use of the slider control The range of the slider is 10Hz 100kHz Mode Panel There are two measurement modes provided Precision and HiSpeed In the precision mode a settling algorithm is employed to produce the most accurate and stable data In high speed mode only a single measurement is taken at each frequency to provide maximum sweep speed Gating Panel Gating is a technique where the oscillator and meter are both turned off on in a synchronous repetitive pulsed fashion This is often used during SPL measurements to remove the reflections of boundaries in the measurements Further information on gating 15 covered in the following pages Meter Filters 1 amp 2 The con
131. ance vs Freq 30 60 90 120 5 10 Hz 20 180 150 180 100 200 500 1K 2K 5K 10K 20K 40K LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu 8 6 Curve Editor UT Import Curve Data File Export Curve Data File Export Graphics to File Export Graphics to Clipboard Curve Capture Curve Editor The Utilities Curve Editor menu item will open a dialog which provides graphical editing and creation of curve data The tool button as shown above on the Utilities toolbar can also be used to activate this item Macro Editor MOF Editor The Curve Editor is a specialized drawing program which allows you to modify or create Library Curves by editing an array of control points or nodes This special edit curve is drawn as an array of straight line segments between the nodes Nodes can be added deleted or moved to create virtually any desired curve shape The edit curve can also be created by reading the data of an existing Library Curve entry or can be used to write a Library Curve entry The number of nodes on the edit curve or the number or data points in a Library Curve are typically different The Curve Editor is also equipped to display existing Library Curves from the system along with the edit curve Many different alignment snap tools are provided for editing the no
132. and has not yet been Editor saved you will be prompted to save it first Preferences Cris Es File New changes the name of the library to Untitled and initializes and or clears some of the various system param eters including the curve entries You will be required to set a real name before the program will allow you to save the library file 2 LMS Untitled lib File Graph Analyzer Processing Utilities Scale View ToolBar Help gt RP EE LE Jun 27 2000 Company File Untitled lib Wed 3 51 am ee ot Maer e P m 100 Abs _ Rel Hj N A Rig LMS 4 1 47 User Manual File Menu 48 Chapter 4 4 2 Open p Ctrl i g 2 9 B El eb Fal E Reopen a ii The File Open menu item opens an existing library aves Revert The accelerator key CTRL O can be used to activate this item using the keyboard or the tool button as shown above Load QuickSet File Save Duick Set File Print Ctrl F Editor Preferences If your existing library has changes and has not yet been saved you will be prompted to save it first Exit Ctrl File Open presents a dialog to choose the library file to open Library files have an LIB extension Depending on the various options in the File Preferences d
133. anual Scale Menu Chapter 9 216 LMS 4 1 User Manual Chapter 9 Scale Menu Parameters Fe Auto F8 Up The Scale Down menu item will decrease the vertical scale range for the currently displayed scale units The tool button as shown above on the Scale toolbar can also be used to activate this item This feature is heavily utilized The Scale Down function instantly decreases the display range For dB scales the Max Min ranges are decreased by the value per division For fixed scales the range is decreased to the next appropriate decrement Note Decreasing the scale moves curves up The Left Vertical scale is always controlled by this function However control of the Right Vertical is optional depending on the setting of Auto Up Dn Right Vertical Data in File Preferences LMS 4 1 217 User Manual Scale Menu Chapter 9 218 LMS 4 1 User Manual Chapter 10 LMS 4 1 User Manual View Menu View Menu 10 amp amp 5 5 amp AB Zoomin Shift Add oom Out Shift Sub oom 1x oom a Shitt F oom 4x Shitt F4 oom oe Shift F8 Redraw 219 View Menu Chapter 10 220 LMS 4 1 User Manual Chapter 10 LMS 4 1 User Manual View Menu 10 1 Zoom In Zoom Out Shit AAA ee Zoomi Shift F1 doom zZX Shift F2 lt oom gs Shift F4 os Shift F8 Zoom In Hedraw Ctri f The View Zoom In Zoom Out menu
134. ard Add will ZoomIn and Sub will ZoomOut Popup Menu The popup menu 1 activated when you right click the mouse button This menu will appear locally at the cursor position The first item Edit Mode 15 only active when a mode other than edit is currently in operation such as zoom or node insert delete This item will change the mode back to edit and restore the default cursor The Question item activates an information mode and changes the cursor to a question mark When the cursor is moved to an object on the graph and clicked a message box will appear describing the object This same function can be activated by clicking on the panel in the upper left hand corner of the graph This function is very useful if you wish to know the name of a curve on the graph or need to know its exact frequency or value Clicking on a blank region of the graph will display general information about the number of nodes and guidelines The frequency and value of the first and last nodes is also displayed The Zoomin ZoomOut provide instant zoom without changing the cursor Insert Node Delete Node and Select All perform identically to the functions listed on the main menu The same is true of Save and Revert LMS 4 1 User Manual Chapter 8 Utilities Menu Ej malade ae gag z Tool Buttons On the left of the toolbar 12 tool buttons are located These functions are identical to the previously described menu items Moving
135. are not allowed Using the Prefix you can produce units of KHz uHz MHz etc When the scale is Linear the Major Div and Minor Div values will be enabled For Log grids only the minor division value is relevant A data grid is displayed with three buttons Make Clear Sort Once you have selected the type of scale and the Lo Hi end frequencies clicking Make will generate a suitable list of labels for the scale The generated labels are then listed in the data grid The auto generated labels are placed at major divisions for Linear scales and at 1 2 5 locations for Log scales If you wish to delete the entire label list click the Clear button Single labels can be deleted simply by erasing the text in the desired entry Additional labels can be added using the empty locations further down the list Clicking the Sort button will sort the list based on the frequency represented in the label text Note The labeling controls will be disabled if the Automatic Labels option is enabled in File Preferences 208 LMS 4 1 User Manual Chapter 9 Scale Menu Frequency Time WIE Hang Division 4 Linear 25 0000m Major 10 JL 9 bim 0 0000 Minor 5 iv Peck Unit 4 7 5m Pale Prefix El 35 mes Horizontal Time Scale The time scale appears when displaying time domain data The time scale is always Linear The Min and Max parameters define the ends of the scale In most cases the Min tim
136. ary The Copy button will copy the selected curves to the Window s Clipboard The Paste button will paste the copied curves from the Window s Clipboard starting at the currently selected curve entry If the block of copied curves extends past the last entry they will be wrapped around to the top of the library This provides the means to move or copy curves from one location to another Since the clipboard is used a different library can be loaded and the curves pasted into that library The Paste button will only be enabled if one or more curves are present in the clipboard When a curve is present the Paste button will show hint text containing the name and parameters of the curve For multiple curves a list of the original curve entry numbers will be displayed The Delete button will delete the selected curves from the library Deleting all of the curves at once can be performed by pressing CTRL A and then using Delete Check Boxes The check box Same Line Type will force the same line attribute settings for all curves This means color width and line style Right Lighter will make the right side vertical data curve such as phase a lighter color shade then the left vertical data curve This is sometimes useful for distinguishing between the left right data shown on the graph The Left Magnitude and Right Phase check boxes enable disable the display of either vertical type data on the graph Table Grid Columns The Curve column
137. ate of the cursor can also be controlled by entering a numeric value in the edit box 61 File Menu ASPHALT i THUNDER RIBS MARBLE DARKGRAY y 2 v 72 Pus 0 y cu E 62 aoe HS s Id SPATTER REDCARPET LIGHTGRAY COBBLESTONE BRICKWALL SPACEGEARS Chapter 4 Relative Cursor Mode Horz Data When taking relative cursor measurements this option provides two different readout modes for the horizontal data You can have the horizontal value represent the absolute true value at the cursor or the horizontal difference between the reference point and the current position of the cursor This would be similar to what happens with the vertical data Optional Library File Data These options determine whether some configuration parameters will be treated as global or library specific For example when opening a library file one may wish for the current graph fonts and color settings to remain unchanged Likewise one may wish that the toolbar locations remain the same and not be affected when a library is opened Conversely if you want to restore all of the full configuration elements by each library file when it 15 opened you can enable these options Control Bar Texture These are selectable backgrounds which can be WALNUT used in control bars located at the top and in the Tool Box FX XD cm me wx ms The color
138. been completed and the computer rebooted go to the Start Menu and locate the entry LinearX gt LMS gt LMS Application a F pone LA FilterShop LMS Application Quic LMS Help uic a LMS Headme Rese a LMS Release Haut 8 a LMS Uninstall saris ku Silice If during installation you also chose to install a group folder of icons on your desktop you may also start the program from that location as well If you have installed the program to a different folder directory than the default the tutorial files will not be automatically loaded when you start the program the firsttime You will need to select Filel Open from the menu and locate the files in the actual installation folder 2 LMS Sample lib File Graph Analyzer Processing Utilities Scale View ToolBars Help amp amp amp lt vw SPL vs Freq atl 4 132 Abs Re NA let LMS 4 1 User Manual Chapter 1 2 LMS Sample lib File Graph zum Processing Utilities Installation 1 6 Microphone MDF Setup Probably the first task to be performed is to load the MDF file for your microphone The MDF file should have been copied during the program installation and will be located in the L
139. being read using 20 40 and 80 points The end points of the Library Curve are always included in the node array The choice of density depends on your application In some cases you may wish to transfer hundreds of data points and in other cases only a few You can always add or remove points as well during the remaining editing 190 LMS 4 1 User Manual Chapter 8 Writing Library Curves Utilities Menu Writing a Library Curve from the nodal edit curve produces uniform high density data The number of points written to the resulting Library Curve is again defined by the Points field The frequency range is the system horizontal scale RECT All nodes must have consecutive frequencies With the exception of the end nodes each interior node must have adjacent nodes above and below in frequency The sample here shows a node backcrossing over a lower frequency node This is an invalid condi tion The program will check your node data when you attempt to write a Library Curve and inform you if this condition exists Although the Curve Editor is always reading writing with data in two different vertical arrays you may only be editing or interested in the data of a single array and ignoring the data in the unneeded vertical array It is not required that you edit the nodes in both of the vertical arrays but only the arrays you require
140. bvious that the smaller the environment and the nearer the boundaries are to the test area the higher the low frequency limit will be Gated measurements made in residential household living rooms usually must be gated to 2 or 5 mS at most which means a response down to only 200 500Hz However the effectiveness of gating can be easily illustrated by the figure below Herea three way cabinet was measured using the ground plane method with a nearby boundary placed very close at 1 meter away The mic distance was also 1 meter The solid curve shows the gated response while the dotted curve shows the normal sweep response The sweep frequency range is 200Hz 20kHz with both curves taken at 300 data points to pick up all of the reflection effects E SPL vs Freq MEER D HH HH HE A B HB Ee es Ee Ee eem Comparison of Gated and Normal Sweeps LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications With the gate METER ON time of 2 3mS the sweep terminates at about 435Hz As the solid curve shows the gated sweep starts to break up as it approaches 435Hz This is due to only 1 to 2 sinewave cycles passing through the meter window with non perfect delay timing The gated response above IkHz is extremely smooth with no sharp reflection effects shown The dotted line showing the non gated normal sweep shows exactly the effects of boundary reflections There is a very noticeable spiking thr
141. cales a curve using the dB value The SCALE keyword is used to offset the magnitude of a curve up or down by the amount given by dB The first parameter is the entry number for the curve to scale and must be an integer 1 through 50 The second parameter is the dB value to adjust the curve by and is a real number Example 100 SCALE 12 6 0 LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs SETSCP index value Set an SCP value The SETSCP keyword is used to change a value of a System Control Parameter The index can be an integer including 3 8 14 15 18 40 46 and the value can be any real number SCP index Function 3 1 Enable MDF Correction 8 Set dB Div 14 Enable Left Magnitude curve display 15 Enable Right Phase curve display 18 RT60 Delta dB 40 DelayStartS weep 0 1115 units 41 DelaySettleReads 0 1mS units 42 DebounceF10k 0 1mS units 43 DebounceFlk 0 195 units 44 DebounceF100 0 1mS units 45 DebounceGain 0 1115 units 46 DidNotSettle Display Time 0 1mS units Example 100 SETSCP 31 1 0 SETVAR variable value Set variable value The SETVAR keyword is used to assign an integer value to a variable name The variable parameter must be defined with the VARLABEL command before using this command The value should be an integer Example 100 SETVAR X 129 SMOOTH entrynumber octave Smooths a curve using octave width The SMOOTH keyword is used to level out or smooth
142. cations are also possible In the graph below the Black curve was frequency translated by a ratio of 0 50 as shown in the Red curve 2 SPL vs Freq 30 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K LMS 4 1 111 User Manual Processing Menu Chapter 7 B Multiply by jo This operation multiplies the curve data by the complex radian frequency at each point This operation effects both the magnitude and phase The phase curve will have 90 degrees added everywhere It is useful for converting inductance curves to impedance or impedance curves to inverse capacitance and other applications In the graph below the Red curve is the result of the operation applied to the Blue curve Voltage vs Freq aBm 30 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 112 LMS 4 1 User Manual Chapter 7 Processing Menu Divide by jo This operation divides the curve data by the complex radian frequency at each point This operation effects both the magnitude and phase The phase curve will have 90 degrees added everywhere It is useful for converting impedance curves to inductance or inverse capacitance curves to impedance and other applications In the graph below the Red curve is th
143. ccur during general operation then it may be necessary to choose a lower baud rate Linking The large Start Link button 15 used to manually open and close the communi cation link from this interface dialog box When the link is active the text in the button will change to End Link When the button is pressed with the link active the link will be closed Therefore this button is used to manually toggle the link ON and OFF LMS 4 1 User Manual Chapter 6 LMS 4 1 User Manual Analyzer Menu The Automatic Link check box provides the means to allow the software to establish the link automatically each time the software is started Using this feature eliminates the need of using this dialog box each time to open the link The software automatically closes the link upon exit In order to use this feature you must have the PAC unit connected and with power ON before starting the software When the link is activated or deactivated the PAC unit will produce a confirmation beep to acknowledge the status change System Power This group box contains a number of readouts which display the current status of the battery inside the PAC3 unit PAC4 units do not have a battery This data is updated each time the link is activated or when the dialog box is re displayed Note These indicators apply only to the PACS If you have a PACA the Battery Status will always indicate Fully Charged with ChrgAmps at 0 000 when the link Is active Fully
144. ch will be available as well on those computers Typically you will need to use standard Windows TrueType fonts such as MS Sans Arial etc Editing amp Placing Vector Images Vector formats provide the most powerful editing capabilities You can modify the content change the colors reassign fonts or add delete items from the artwork Unfortunately they also produce the most trouble with portability and have a nasty habit of locating any and all bugs in the other application s import filters However with a little experimentation and testing you should be able to determine which formats and applications will achieve the desired results For best editing use the AI format with Adobe Illustrator WMF Formats If you will be importing WMF files into other graphics applications you may often need to use the WMF Placeable format and not the WMF Standard The placeable format contains an additional header which many applications require Both WMF formats contain full RGB color information The fonts used in your design must be available on the computer where the WMF file is used Note Many applications do not handle rotated text correctly in the WMF format EMF Format This is the new 32 Bit format of the previous 16 Bit WMF format This version has many improvements over the old WMF format When possible use this format instead of the WMF The EMF format contains full RGB color information The fonts used in your design must be available
145. ch performs re indexing of the horizontal data points of a curve entry The tool button as shown above on the Processing toolbar can also be used to activate this item In most cases the horizontal data is frequency but it could also be time or angular position information This dialog reprocesses and interpolates the vertical data based on a new linear or log array of horizontal values A common use for this operation is to reduce the resolution of a curve For example a curve containing 500 data points can be realigned into a 100 point curve This could be within the same frequency range or a different frequency range This routine can also be used to simulate higher resolution using quadratic or cubic interpolation and increasing the number of data points Both of these methods will produce curvature rather than straight line segments However be aware that itis impossible to create data that was not originally present For example if the original frequency range was 100Hz 1kHz and you realign the data to 1OHz 1kHz there is no original data below 100Hz The result is a flat line segment from 10Hz 100Hz at the value of the original 100Hz data point When changing the horizontal data from linear to log there will be a loss of resolution either at the low end or high end of the spectrum The curve list box provides selection of the library curve for the operation This special list box shows the type of data contained in each curve A
146. ckSet files which will be used by your macro program The Analyzer Parameters are setup during the macro by loading previously saved QuickSet files You cannot program each parameter individually Instead you will need to set and save one QuickSet file for each setup your program requires Curve libraries can also be loaded by the program so any curves to be used as standards will need to be prepared first and saved in a library In the program you would then want to load this library so the appropriate curves are there when needed If you need to change scale settings this is also handled by loading curve libraries All of the scale information is saved in curve libraries as well LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs 13 7 Macro Command Reference The following listing gives the macro commands currently supported in the LMS system Some of the commands have changed for use under Windows vs DOS The macro commands or keywords cause the LMS system to perform certain tasks or tests These encompass far more than simply running sweeps Some of the keywords will need no additional information while others may require certain parameters These parameters may be messages variable labels or other data All of the macro keywords have names which lend themselves to help understand the functions they perform This makes the program very easy to read and comprehend what is occurring throughout its operat
147. cs to File Export Graphics to Clipboard Curve Capture Curve Editor Macro Editor F4 Editor Polar Convertor LMS 4 1 161 User Manual Utilities Menu Chapter 8 162 LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu 8 1 Import Curve Data File Utilities E ER RS ES Import Curve Data File E Export Curve Data File Export Graphics to File Export Graphics to Clipboard Curve Capture Curve Editor The Utilities Import Curve Data File menu item will open a dialog which imports text file data into library curve entries The tool button as shown above on the Utilities toolbar can also be used to activate this item Macro Editor MOF E ditor This dialog supports many different kinds of formats and will generally operate in a universal fashion for almost any kind of file data The only requirement is that the data be contained in ASCH columns of data points It also provides many different kinds of automatic translations during the import process The maximum number of data points allowed is 4096 If your file contains more points than this an error message will appear and truncation of data will result The data file format 1s relatively simple as follows Lines starting with any char other than space or numeric are treated as comments Data lines have two or more columns as defined by the format Each value in a data line can be delimited by space commas or tab
148. cted to the signal ground and pin 2 the active output line The Output XLR line has an output impedance of 500 Ohms This is to facilitate direct impedance measurements with only a 2 wire hookup Microphone E Input Line JJ Input Oscillator Output LMS Interface Cable Installation Chapter 1 Note f you will be connecting the LMS output to a power amp or other device with unbalanced inputs you will need to make sure that Pin 2 of the output line is connected to the active input line of the power amp or device Remember Pin 3 of the LMS output is a ground line not a signal line The figure below shows the LMS connectors and their functions This sche matic can be used to construct other useful cables for special purposes or to provide easier hook up for various tests A common requirement is that of loudspeaker impedance testing For this type of test pins 2 and 3 of the output line need to be connected to the speaker s terminals Pin 1 is not used 500 Audio Out Output Common Ground Computer Chassis Balanced Line1 Input Bal Input Common Computer Ground Chassis LMS Mic Input LMS Interface Cable Pin Functions 8 LMS 4 1 User Manual Chapter 1 LMS 4 1 User Manual Installation It is a good idea to construct a short cable consisting of a female XLR with 2 single wires from pins 2 and 3 terminated to two alligator clips This cable would then be plugged int
149. ction Fiat x v Track Ratio 1 000 Frequency 448 813 Gate Timin Ose Off 20 0000m Sec OscOn 20 0000m Meter 5 0000m Sec Meter On 10 0000m Sec 2 Import SAMPLEMB WY Z GDT LMS 4 1 User Manual 43 Getting Started 3 5 The Scale System Chapter 3 SLMS Test lib The heart of the curve graphing system is the Scale Parameters Scale Parameters dialog This dialog controls how every type of curve is displayed and also defines the number of divisions on the grid as well as the labeling on all axis The dialog is organized into two sections horizontal scales and vertical scales Each type of data has it s own scale definition Most of the fields and parameters are self explanatory but are explained in full detail in the Scale Menu chapter The scaling system may seem somewhat complex when you first start working with it However as you work with it more you will quickly see that all of the vertical tabs contain essentially the same information Scale Parameters V ertica Inductance Capacitance Excursion Velocity Acceleration Time Phase SPL Voltage Current Impedance Ratio Asi Division Linear Major 12 f Lag F d l Minor 2 Bipolar Per Div 2000 Positive ek Ret 1 Horizont
150. curs automatically as different curves are selected for display Since there are only 8 text lines in the graph notes and 4 lines in a curve entry info only the notes from the first two displayed curves can be shown in the graph notes area The other two options Copy Info Text to Left Right Notes provide a manual method to transfer the content of the curve info to the graph notes when desired Curve Info Curv 1 P25 at 1H Horz Range Left Vert Right Vert Polar Freg 10 2 40 0E Hz SFL Fhase 0 0000 Inf GP ATI Parking Lot 11 13 82 2 837 at Amp 25Ft 18Ga Twisted Pair Transfe ony Ate Graphhotes P Copp ata bn Bight Graph dates Auto Copy Cancel 73 Graph Menu Chapter 5 T4 LMS 4 1 User Manual Chapter 5 LMS 4 1 User Manual Graph Menu 5 3 Notes amp Comments Graph Parameters C ES 9 The Graph Notes amp Comments menu item will open a dialog which allows you to enter user defined notes and identification information The tool button as shown above can also be used to activate this 1tem Automatic Curve Info Notes Ifthis feature is enabled the graph note fields are filled automatically from the curve entry info fields Manual editing of the notes is disabled Left Page Right Page There are eight lines of possible notes which can be entered four on each of these two tabs The note lines will appear on all of t
151. d down to provide an initial comparison window When the limit curves have been constructed run the Processing Curve Compare Select the proper entry numbers for the test Max and Min curve entries Once the entry numbers are set click the Ok to run the comparison If the test passes you will hear a confirmation beep If the test fails vou will see a dialog message noting the frequency that failed and by how much To begin the procedure for the next speaker start another sweep by hitting the F9 key This begins the whole sequence once again The sequence of key strokes for the remaining speakers in the test batch once the first setup test is performed is summarized below Run Sweep Processing Curve Compare LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications Automatic Testing The previous procedure would certainly be reasonable if only a few tests were to be done however for normal production on a regular basis an LMS Macro Program will make the process fully automatic and much easier The macro program must be first written to perform the necessary series of sweeps and utility operations This is fully explained in Chapter 13 Writing the program can be done in as few as 5 to 10 lines The LMS programming commands are very powerful and concise Another advantage of this technique is that no specific knowledge is required by the operator All that the operator will need to do is press the
152. d from the minimum phase transform This phase curve does not contain the delay components that were present in the summation response method The reason for this is that the minimum phase transform has no way of knowing whether a single driver produced the response or a combination of drivers through the use of a crossover The phase response produced from the summation of the individual ranges is the actual true phase for the system This method can and should be used when the total phase of a system is required which contains the non minimum phase components caused by multi way crossovers While the magnitude response curves are the same the phase response differences between the two methods will produce very different time domain graphs The two graphs on the following page show the step and impulse responses derived from the minimum phase and magnitude The top graph shows the step and impulse responses derived from the phase and magnitude of the summation system curve dBSPL 100 90 40 Minimum Phase response for System 303 SPL Applications Chapter 14 It can be clearly seen in the lower graph that there is significantly more time delay present Also the phase reversal in the region of 0 5mS is quite different than that of the upper graph Voltage vs Time L ee Step Impulse response from Minimum Phase Voltage vs Time a Step Impulse response from Summation Phase 304 LMS 4 1 User Manu
153. defects in a speaker There are many different types of problems a speaker can develop No single test will catch all of them The sweep of a good transducer should produce a curve that largely follows the noise floor of the LMS system When a rubbing buzzing device is tested a large rise in the curve should result Typical variations of anywhere from 5dB to 40dB have been observed Note This is a tracking bandreject type of sweep The LMS system should be in good calibration to produce a low residual feed through of the fundamental If in doubt run the INTERNAL CAL As a simple test of the system a speaker can be placed with the cone facing up on a table or floor and a small object such as a penny placed on the cone to vibrate The object should be non magnetic Run two sweeps one with and one without the object on the cone A sizable difference should exist between the two curves 329 Chapter 16 Misc Applications Voltage vs Fre Woofer Units Tested for Rub Buzz Voltage vs Fre Woofer Units Tested with Flat Filters LMS 4 1 User Manual 330 Chapter 16 LMS 4 1 User Manual Misc Applications 16 4 Creating Curve Data Manually There are many occasions when curves may need to be manually created by the user You may wish to enter data from other test equipment that is not computer based special curves of EQ or corrections or limit curves for use in PASS FAIL comparison operations This may sound like
154. depth of these texture patterns vary from 4 Bit to 24 Bit Depending on the mode of your video system some may not be suitable for display FA ihe i X Se 3 SMOKE SA NDSTONE Hi qe es i ai RAINDROPS POLISHEDMETAL You can create your own bitmaps as well and place them into the ControlBarTexture folder The program will automatically load them for selection the next time it is started There is also a palette file LMS PAL which should be used if you are creating 256 color bitmaps All Ces sw files must be BMP format CLOUDS x f BLUECARPET ET ATOMS FIREWORKS LMS 4 1 User Manual Chapter 4 LMS 4 1 User Manual File Menu Analyzer Configuration The fields in this panel represent some of the calibration and or operational control data for the analyzer There are also a couple of additional check boxes which enable disable certain specific system functions Most of these parameters should not be changed by the user The two exceptions are the TTL pulse width and RT60 threshold delta These values can be adjusted as needed by the user Preferences General Analyzer Configuratia Enable Mic Input SPL Mic Setup Enable Gain Auto Ranging Enable Line Input SPL Mic Setup DNS Display Time Sec 40 0000 TTL Pulse width Sec 01000 Min Time Per Step Sec 0 1000 Settle Limit Acoustic dB 2 0000 Delay Start Sweep Sec 1000 Settle Limit Electric dB 0 2000
155. des You can snap to the grid guidelines or existing curves A scale system is provided independent of the main system The Curve Editor operates on two different types of curves Left Vertical and Right Vertical An individual edit curve is provided for each of these types of data You may edit only a single curve or both of the two curves depending on your requirements The curve list box provides selection of the library curve for the read write This special list box shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry 181 Utilities Menu Chapter 8 E Curve Editor Left Vertical Imp Control Graph Node Show Snap View Help exe ajaj Hels ale Glolol 22 Curve 8 P25 1M Tails Freq SPL Phase Points 500 Read Write 325 5724 Hz 8 6618 Ohm Curve Editor Screen When the editor dialog window first appears itis automatically sized to cover the majority of the program s screen This is a dialog window and you cannot use other features outside this dialog while it is open The Curve Editor is virtually a program itself with its own menu and toolbar Vertical scale controls are located on the toolbar along with several controls for reading writing Library Curves located
156. det Blocked Woofer imp Impedance vs Fre LMS 4 1 133 User Manual Processing Menu Chapter 7 Parameters and simulation results for the LEAP Model Blue curve is the input and Red curve is the simulation Note that both the magnitude and phase match the original data much closer than the Standard model Speaker Parameters 45 Blocked Woofer Freq mp Phase 8 Freq me a E Inf Baffle 100 s C Impedance vs Fre EEE pS A LI n oe HG i RER FERRER as ER Y 4 4 ER 134 LMS 4 1 User Manual Chapter 7 LMS 4 1 User Manual Processing Menu Single Curve Elec System This method is used when you only require electrical parameters for a loudspeaker The resulting parameters are the electrical motor and the Q values representing the mechanical resonance system There are only two Input Parameters that need be specified the curve containing the reference impedance data and the Revc value Revc is the DC voice coil resistance as typically measured with a DMM In the Model Simulation panel choose a curve entr
157. dialog to close Microphone Setup Interface Macro Run Calibration This dialog is modeless meaning that it does not lock out other operations in the program You may leave this dialog open and continue to open other dialogs or activate other program functions This dialog also supports the Roll Up Roll Down feature When leaving this dialog on the screen it is helpful to reduce its size so that the graph underneath is visible The first double arrow button in the top right corner of the title bar controls this feature However you can also control the roll function by using the CTRL PgUp and CTRL PgDn or the toggle key F2 There is also an option in the File Preferences dialog which controls the automatic roll up during a sweep This allows full view of the graph during a sweep Analyzer Parameters Oscillato Mad Mater Filter 1 Output Level 396 883m d v C HiSpeed Data Filter Function Flat 2 eater 100 253 z Tack 1 000 Gatin II Du Frequency 100 289 Meter Filter Filter Functian Fiat Track Ratio 1 000 Frequency 100 289 Data Curve Graph Name 1 P25 at 1M Freq SPL Phase Lo Freq Hz HiFreq Hz Points Directio 100000 1096 E Dn C Up i TTL Pulse Gate Time Calculator Gate Timin Osc OF 200 0000rn Sec Ose On 50 0000 Meter Di 50 0000 Sec Meter 100 0000m Sec 79 An
158. ds Ctrl F a A Cut Ch Ctrl C Uperations Print Ctrl F Faste Suntax Check Ctrl G Delete Ctrl Del Macro Ctril A m Select All E E amp oo MA Rec The tool bar replicates most of the commands from the menus The function of each tool button can be found by moving your mouse over the button and reading the hint about each button Most of the buttons are self explanatory The Syntax Check provides a simple means to verify your script prior to running When you click this button or select it from the menu a message box will appear if there is a problem If no problems are found then only a confirmation beep is produced Syntax checking covers the following program structure e Line numbers present on all lines except if blank Keyword commands are valid QuickSet and Curve Library files can be found The syntax checker does not verify if the parameters for acommand are correct This can only be determined by running the macro 194 LMS 4 1 User Manual Chapter 8 HDF Editor Ea Parameter Model Acoustic 94 0000 SPL Serial 15248 Electric Ref 238800 Author Linea Systems ne Date May 32000 Wed 12 32PM Magnitude dB Phase Deg Index Frequency Hz Load MOF File Save MDF File Load fram Curve 5 MDF 182848 LMS 4 1 User Manual Load Data from Mic Input Load Data from Line Input os
159. e deleted This is the fastest means to delete many nodes at once LMS 4 1 User Manual Chapter 8 Snap View wv Cues wv uides Delete Guides View Help w Vert Guides wv Horz Guides Vert Ruler Grid Horz Ruler Grid Curves LMS 4 1 User Manual Utilities Menu Show Menu This menu allows you to selectively enable disable various items for display When displaying Library Curves only those curves which are enabled for display on the system graph will be shown Guidelines are pulled from the rulers and can be enabled disabled using this menu item The Delete Guidelines menu item will destroy all of the guidelines Guidelines can also be deleted individually by moving them back to rulers To create a guideline move the cursor over aruler click and hold the left mouse button and drag the guideline on to the graph Guidelines can be repositioned at any time Snap Menu This menu allows you to selectively enable disable different objects to be used for snap alignment Snapping the cursor to an object occurs when moving a node or guideline and the cursor is near the object The cursor will jump to the object and remain on the object for small cursor movements Large movements will break the cursor away from the object The horizontal axis is always frequency on all four graphs However since the vertical axis has different units for each graph the vertical axis 1s given the generic name of Value When snap is
160. e ERBEEP keyword is used to produce a beep sound from the computer s speaker the same as those used throughout the program when an error occurs The user can use this command to signal the operator Example 100 ERBEEP B EXITTODOS Exit LMS and Return to DOS This command has been retained for backwards compatibility with old macros but under Windows now behaves the same as the END command Example 100 EXITTODOS 261 Macro Programs 262 Chapter 13 EXPORT entrynumA Name Export ASCII Data File by Name The EXPORT keyword is used to produce a data file The first parameter is the curve number to export the second file name The file will be written to the LMS Export folder if no path info is included in the name An extension of TXT will be used if none is specified Example 100 EXPORT 11 TESTNAME EXPORTCON entrynumA Export ASCII Data File by CurveName The EXPORTCN keyword is used to produce a data file using the first 8 characters of the curve entry name as the export file name The first parameter is the curve number to export The file will be written to the LMS Export folder Make sure that the curve name contains legal file name characters in the first 8 positions Example 100 EXPORTCN 11 EXPORTEN entrynumA Export ASCII Data File prompt for Name The EXPORTEN keyword is used to produce a data file and allow the user to enter a file name each time the command is executed The first parameter is the curve n
161. e an integer 1 through 50 Up to all 50 entry numbers can be listed All entry numbers in the list must be separated with spaces Any curve numbers not listed will be turned off from display on the graphs Example 100 GRPHCURVE 1 3 15 19 20 B GRPHSCRN RollUp the MacroRun Dialog The GRPHSCRN keyword is used to roll up the MacroRun dialog Example 100 GRPHSCRN BH IFCRKEYGOTO line Takes Jump if CarriageReturn Hit The IFCRKEYGOTO keyword is used to check for operator keystroke of the ENTER key This command would normally be used after the PAUSE command Example 100 IFCRKEYGOTO 500 B IFSBKEYGOTO line Takes Jump if SpaceBar Hit The IFSBKEYGOTO keyword is used to check for operator keystroke of the SpaceBar key This command would normally be used after the PAUSE com mand Example 100 IFSBKEYGOTO 500 IF variable value line IF variable value GOTO line number The IF keyword is used to test if a previously defined variable is equal to the value This command provides conditional branching The variable parameter must be defined with the VARLABEL command before using this command If the variable equals the value then the GOTO line number will be executed If not execution continues with the next statement number Example 100 IF X 1 GOTO 130 INC variable Increment variable The INC keyword is used to increment add one to the variable The variable parameter must be defined with the VARLABEL command before u
162. e controls the color and line width of the sub divider border lines between different sections of the title block note block and map block Grid Parameters The Background coloris applied inside the region of the grid itself The Border Line controls the color and width of the border surrounding the grid The Major Div controls the color width and line style of the major division lines drawn on the grid The Minor Div controls the color width and line style of the minor division lines drawn on the grid Font Parameters Fram ne mis Large Frame Line ED Mis There are six tabs in this panel that control the Smal Frame Line Mis fonts used in different regions of the graph artwork The titles are self explanatory The ari Background m color can be changed directly by clicking the Mew Joc Color button and the font can be changed by Border Line 20 Minor Div 5 Sois El clicking the Font button Title Block Graph Title Font Typeface Scale Vertical Scale Horizontal Map Legend Note List Note Win9X has support for line styles other than Solid when using line widths larger Style Size Color aZz Aia 24207 than 1 WinNT4 does support this however LMS 4 1 User Manual non Solid line drawing is extremely slow Post mm Script printing export is always supported 67 Graph Menu Chapter 5 68 LMS 4 1
163. e crossover network This should be done right at the enclosure terminals The next sweeps taken will be at each of the driver s terminals out of the network sections The LMS control panel will be set for anormal VdBm sweep with the filters FLAT and the Line input selected The example here uses a frequency range of 10Hz to 40kHz The top graph on the next page shows the basic results of a 3 way system Next each of the output curves should be divided by the network input curve using the binary math DIV function This produces the individual transfer functions of the passive network sections The response of the power amp itself is cancelled out The lower graph on the next page shows the results From these curves one can easily see the differences between passive crossovers with reactive loading and their ideal alignment equivalents Peaking and non constant slopes are graphically demonstrated HiPass Section Power Amplifier BandPass Section 323 Chapter 16 Misc Applications Voltage vs Fre 150 Ps Voltage Curves of Network Input Outputs Voltage vs Fre Lo Mid Hi Passive Net Transfer Functions LMS 4 1 User Manual 324 Chapter 16 LMS 4 1 User Manual Misc Applications 16 2 Acoustical Rub amp Buzz Testing Traditional Rub and Buzz testing consists of a limited frequency range sinewave sweep with a steep tracking highpass filter set at a frequency about 5 10 times that of the osci
164. e curve Ohms will be written into the SPL entry in place of the SPL phase Example 100 MAKESPLZ 11 20 B MENUSCRN RollDown the MacroRun dialog The MENUSCRN keyword is used to roll down the MacroRun dialog This makes the contents of the workarea and command line visible Example 100 MENUSCRN MICMAKE entrynum Create MDF File from curve entrynum The MICMAKE keyword is used to produce a calibration file for mic correction This command is mainly for factory use The entry number should be that of an entry containing a ratio curve of the mic response vs some reference The sweep range ofthe curve must be 10Hz to 40KHz The entry number must be an integer through 50 When the command is activated it will prompt the user to enter a serial number for the mic file This must be a 6 digit integer from 100000 to 999999 The mic file will then be written to the main LMS Mdf folder as SNnnnnnn MDF Example 100 MICMAKE 11 MUL entrynumA entrynumB entrynumR MUL A B R The MUL keyword is used to produce a multiplication result curve from two other curves All parameters must be integers and between 1 through 50 This is the equivalent of multiplying the curves It can be used on either the graph or menu screens Example 100 MUL 11 12 15 265 Macro Programs 266 Chapter 13 NAMECURVE entrynumber Enter Edit the Curve Name The NAMECURVE keyword is used to enter a name for a curve The entry number parameter must be an i
165. e curves measured from separate drivers and with crossover sections into one final response curve The following example will show the process for a 3 way enclosure like that of the figure below In order to sum the drivers together it will be necessary to know the relative delay positions between the drivers When the minimum phase curves are generated for the individual drivers response no position delay will be included This must be combined into the curves separately The point of reference at which the position of the drivers should be measured is at the voice coil This is the plane of the top plate of the driver or the magnetic gap It is the location at which the signal is converted from electrical to acoustic propagation This is the source of the acoustic wave As the figure below shows the distances between the driver voice coils are measured The velocity of sound is about 100uS micro seconds per 1 37 inches The tweeter has the most forward voice coil position so its delay will be 0 The mid is delayed by 146uS and the woofer is delayed by 220uS behind the tweeter MID DELAY 2IN 2 1 37 14605 WOOF DELAY 1 37 22005 297 SPL Applications 298 Chapter 14 The graph below shows the direct measured response of the complete system with all drivers active The goal will be to duplicate this response from summing the individual response curves together with the correct minimum phase and position
166. e is set to zero 3 jo The Major Div and Minor Div values describe the design of the horizontal grid Using the Prefix you can produce units of mSec uSec nSec etc A data grid is displayed along with three buttons Make Clear Sort Once you have defined the Min Max time values clicking Make will generate a suitable list of labels for the scale The generated labels are then listed in the data grid The generated labels are placed at the major divisions of the horizontal grid lines If you wish to delete the entire label list click the Clear button Single labels can be deleted simply by erasing the text in the desired entry Additional labels can be added using the empty locations further down the list Clicking the Sort button will sort the list based on the time value represented in the label text Note The labeling controls will be disabled if the Automatic Labels option is enabled in File Preferences LMS 4 1 209 User Manual Scale Menu 210 Chapter 9 EET Frequency Time Angle 150 120 WIE Division f Linear 1800000 0000 Major 2 2 bur F600000 Minor 2 Pla Rect Unit 30 Frefi Polar GE Srt Horizontal Angle Scale The angle scale appears when displaying polar curve data The angle scale is always Linear The Min and Max parameters define the ends of the scale These are fixed at 180 deg and 180 deg The Major Div and Min
167. e required to test a given size capacitor Large capacitors will require low test frequencies and small capacitors require high test frequencies The usable measurement range for capacitors is approximately 0 01uF to 1 000uF Capacitor Curve Examples The graph below shows three examples of capacitor curves 60uF electrolytic 12uF mylar and 2 7uF mylar Looking at the curve for the 2 7uF cap we see that the curve has a sharp break point at 60Hz For frequencies below this the measurement has become limited by the 1000 Ohm maximum impedance At the higher frequency end there is a peak reached at 80kHz This is due to a resonance occurring with the cable inductance Between 100Hz and 1OkHz it is clear that the capacitance is very constant and has little frequency dependency The curve for the 12uF cap shows it just reaching the lower limit near the end of the frequency range at 10Hz At the higher frequency end a small resonance occurs at 30kHz with the cable inductance and then the value falls off due to the cable resistance limitation VS d bac sl JENELUNED tn LE Hi T Mylar Cap TCI az SR LL SLT 1 2 NO EIE HE T H BIDOU E E EE mi Bis BE og gg DE T Examples of Capacitor Value Sweeps 345 Misc Applications 346 Chapter 16 The valid range of significance
168. e result of the operation applied to the Blue curve Voltage vs Freq 70 H HEF io FRET 100 Er LEGS 110 10 Hz 20 50 100 200 500 1K 2K 5K 10K 40K LMS 4 1 113 User Manual Processing Menu Chapter 7 Real cos This operation returns the real portion of the complex curve data by applying the cos function to the phase and magnitude data The resulting phase curve will be either or 180 degrees This operation effects both magnitude and phase This operation can be useful in separating the resistance from complex impedance or other similar applications In the first graph below the Red curve is the result of the operation applied to the Blue curve B Imag sin This operation returns the imaginary portion of the complex curve data by applying the sin function to the phase and magnitude data This operation effects both the magnitude and phase The phase curve will be either 90 or 90 degrees This operation can be Impedance vs Freq Deg useful in separating the reactance from complex impedance or other simi lar applications In the graph below the Red curve is the result of the operation applied to the Blue curve 114
169. e will be inserted as the curve name You can change the name later to whatever you prefer The program also performs a wide array of housekeeping chores by filling in various types of comments into the nfo curve fields automatically For example when sweep measurements are taken a date time stamp note is placed in the Info fields denoting when the measurement was taken 69 Graph Menu Chapter 5 Parameter F Data l Same Line M Left Magnitude 1 Cuve Show All HideAl _ cu M Paste X Delete D RightLighter I Right Phase C13 1M Tails 10 2 40 0KHz SPL Phase Width Color 4 1 M P25 at 1M Yes 10 2 40 0KHz SPL Phase 552 Solid 2 2 v C13at 1M No 10 2 40 0KHz SPL Phase 552 Solid 2 3 M D25 at 1M No X 10 2 40 0KHz SPL Phase 552 Solid 20 4 P25 at 2M No 102 40 0KHz SPL Phase 552 Solid 2 5 C13 at 2M No X 10 2 40 0KHz SPL Phase 552 Solid o0 E D25 at 2M No X 10 2 40 0KHz SPL Phase 552 Solid 2 of P25 1M Tails Yes 10 2 40 0KHz Time Phase 552 Solid 20 8 P25 1M Tails Yes 10 2 40 0KHz SPL Pha 9 C13 1M Tails 10 2 40 0KHz S se 552 So and 10 D25 1M Tails No X 10 2 40 0KHz SPL Phase 552 Solid 2 11 C13 Again Yes 10 2 40 0KHz SPL Phase 552 Solid 2 12 Woofer Covered No X 102 40 0KHz SPL Phase 552 Solid 20 Cancel Help Parameters
170. each of the different types of data The scale and ruler values will change to match each graph and type of data Node Menu This menu provides the basic node operations of Insert Delete and Select All Tool buttons are also provided for each of these menu items Insert This menu item begins an insert mode and changes the cursor to the node insert icon You can move the cursor to any location click the left mouse button and a new node will be inserted Nodes are always inserted between two closest nodes To exit the insert mode you can select the item again press the ESC key or use the right mouse button and choose Edit Mode from the popup menu Note Another method of inserting nodes is also supported while in the normal editing mode By simply pressing the Insert key a node will be placed at the present cursor location Delete This menu item begins a delete mode and changes the cursor to the node delete icon You can move the cursor to any existing node click the left mouse button and the node will be deleted whether or not it is selected If you are not within the capture range of a node an error message will appear To exit the delete mode you can select the item again press the ESC key or use the right mouse button and choose Edit Mode from the popup menu Note Another method of deleting nodes is also supported while in the normal editing mode By simply pressing the Delete key all currently selected nodes will b
171. each toolbar will be checked If the toolbar is outside the main program window it will be brought within the bounds of the program window This function along with the Hide All can be used to locate toolbars which are off the screen and force them back into view An example with all of the toolbars visible is shown on the following page 229 Toolbars Menu Chapter 11 2 LMS Lms lib MITES File Graph DRA Processing Utilities Scale view ToolBars Help t s Scale F4 1 ES ES E3 fel lud fol Rx m PA 5 ES d pee En pae LII RE EH z co E 6 TESTING Jul 03 2000 File Lms lib Mon 3 45 pm EP AL TE AN 1 100 Abs Rel lat 230 LMS 4 1 User Manual Chapter 11 LMS 4 1 User Manual 11 2 Hide All Toolbars Show All Hide All v File w Graph w Analyzer v Processing w Utilities Scale wv Toolbox Toolbars Menu The Toolbars Hide All menu item will remove all of the toolbars and the Toolbox Toolbars can be removed from any of three locations the top control bar the Toolbox or as single floating windows When a toolbar is added or removed the control bar or tray will resize When all of the toolbars are removed the con
172. earranged simply by grabbing the handle on the left of each toolbar They can be docked into any of the three trays or dragged onto the screen by themselves as a single floating window They can also be enabled or disabled for display Toolbox Control bar Tray 2 LMS Sample lib ME File Graph Analyzer Processing Utilities Scale View ToolBars Help Jamon nonl SPL vs Fre FEN 2 Tm Graph Notes Ll Processing li eS SRST mos moms m P25 at 1M C13 at 1M PIECE D25 at 1M GP ATI Parking Lot 11 15 52 2 82 V at 25Ft 1863 Pair J 400224 Person Project Jun 13 2000 l INEAR X 100 Abs Rel 1 P25 at 1M 19 081 Hz an 76 522 dBSPL tet Right 17 General Features Cursor Marker 18 Chapter 2 2 2 Tracking Cursor In the bottom status bar the cursor system readouts are shown The cursor will track any data curve based on the points in the curve To move the cursor to another frequency quickly double click the left mouse button at the desired frequency Use the Left Right or the Home End keyboard arrow keys to move along a curve Use the Up Down keyboard arrow keys to change to a different curve in the same curve group To cha
173. ected from any power amp and transducers before turning the meter on Measuring Resistance When the Resistance type is selected the Test At Frequency selection will also be forced Since normal resistors have constant impedance irrespective of frequency the Test At Impedance mode has no relevant use Any convenient frequency may be used Remember that when measuring resistance the cable resistance from the LMS card to the component will also be included For the LMS interface cable this is about 0 3 Ohms LMS can only measure resistance using an AC signal nota DC signal as with DMM devices To measure the DC resistance of inductors use a DMM Measuring Inductance and Capacitance When the Inductance or Capacitance measurements are selected and the Test At Impedance method is used the system will automatically search for a frequency which produces a component impedance equal to the specified test value within 10 It is assumed by the system that the impedance being measured is entirely reactance The system then determines and displays the component value based on the frequency and reactance measured 93 Analyzer Menu Microphone Setup Mic Input Line Input 94 MOF Dat Chapter 6 6 5 Microphone Setup Analyzer Analyzer Ea Parameters Sweep Start Stop Pup B F10 ES d ALC Meter Microphone Setup FAC Interface Macro Run The Analyzer Microphone Setup menu
174. eep is completed you can use the Scale Auto to bring the curve into view Scale Auto 37 Getting Started Chapter 3 SPL vs Fre You should now see a curve similar to what is shown above Your SPL data will of course be different since you are measuring a different object Note that in the Map area justbelow the graph grid there is a single short line in the same color as the curve Now we will put anameonournew curve Select the Graph Curve Library menu item to open the Curve Library dialog Note that curve 1 is now ON and that the number of points and the horizontal freq data items are filed in We can now enter a name for our curve such as My New Curve Click Ok to close the dialog saving your changes Parameter 1 Show All Hide All Delete Delete al Copy Curve Paste Curve B dE 5 Sys wih 1 MyNewCuvd Yes 10 2 40 0KHz SPL Phase 552 Solid 20 2 No SPL Phase 0 Solid 2 3 No SPL Phase 0 Solid 20 e 4 No SPL Phase 0 Solid 20 5 No SPL Phase 0 Solid 2 O No SPL Phase 0 Solid 20 NM O No SPL Phase 0 Solid 2 8 No SPL Phase 0 Solid 20 38 No SPL Phase 0 Solid 20 98 10 No SPL Phase 0 Solid 20 1 O No SPL Phase 0 Solid 2 12 No SPL Phase 0 Solid 2 j oes 0 38 LMS 4 1 User Manual Chapte
175. eep across a frequency range itis important to recognize the limitations of the measurement system and setup There are two basic limitations 1 the LMS system will clamp the maximum impedance to 1000 Ohms and 2 there is always a cable resistance present of about 0 3 Ohms in series with the component These two limitations define the maximum minimum measurement range for the system However even with these limitations 70dB of impedance measurement range is provided and covers the region most commonly used by capacitors for crossover design The figure below shows two curves produced from shorting the output lines together and by leaving them open circuit A frequency range of 10 7 100kHz is used The area between these two curves represents the region where the system can take valid capacitance measurements It can be noted that the shorted cable curve has a slightly higher slope for frequencies above 20kHz This is due to the small inductance also present in the LMS output cable in addition to the 0 3 Ohms resistance ui Capacitance v req Capacitance Measurement Range LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual ER Ig 1000 Z 1000 Ohms all 1 10 Misc Applications The range shown here only covers the capacitance scale from to 100uF By projecting the limit lines to both higher and lower values one can easily judge what frequency range will b
176. enerated This routine also enables the polar curves for display auto matically when the processing is completed and disables the input curves The graph view of the polar curves is now shown on the following page LMS 4 1 User Manual Chapter 8 dBSPL Utilities Menu Curve Frequency Deg Q DI 2 00K 360 1 0 0 0 5 00K 360 1 0 0 0 10 00K 270 1 3 1 2 20 00K 150 2 4 3 8 40 00K 135 Zr 4 3 LMS 4 1 User Manual The beam width Q and Directivity Index are also calculated on the graph for each polar curve frequency The curves show the expected directivity increase with frequency At 40kHz the response is highly directional At 2kHz and below the response is virtually omni directional If the Polar Convertor dialog is now reopened the output curve names appear as shown on the following page A view of the Curve Library is also shown The routine automatically provides names for the polar curves and also places a date time stamp into the last Info field of the curves Since polar curves made by this process are of low resolution a small number of points it can be helpful to use the Data Realign operation to increase the point density This process will produce much better interpolation than the simple straight line segments which would normally be drawn by the graphing system The polar plot on the next page shows cubic interpolation for 400 points 203 Utilities Menu dBSPL 180 SPL Vs Angle
177. ernal Mic or Line setups or by editing the fields manually In some cases you may use a combina tion of several of these If you are creating an MDF file for a new mic you will first need to create the response curve in the Curve Library This can be done by importing the data using Curve Capture or by using the Curve Editor 195 Utilities Menu 196 Chapter 8 Model This is an information text field You can place a short line of text here which describes the model of the microphone Serial This is an information text field You can place a short line of text here which describes the serial number of the microphone Author This is an information text field You can place a line of text here which describes who created the file A person name or company name Date This 1s an information text field You can enter a line of text for the date and or time when the file was created Acoustic Ref This is a sensitivity field Enter the value which defines the acoustic level at which the microphone produces the stated electrical reference output level Assuming the response curve is OdB at this would be the level at IKHz Electric Ref This is a sensitivity field Enter the value which defines the electrical output level at which the microphone receives the stated acoustic reference pressure Assuming the response curve is OdB at this would be the level at IKHz Note You can change the units of the two para
178. ery helpful in selecting the splice frequency 149 Processing Menu Chapter 7 In the top graph below two SPL curves are shown The curves cross in the frequency region of 1500Hz A splice frequency of 1550Hz was selected The resulting curve is shown in the bottom graph The minimum phase response for this curve could now be generated using the Minimum Phase Transform Tail Correction might also be useful prior to generating the phase SPL vs Freq SPL vs Freq TT E Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 150 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Realign Curve Averaging Curve Compare Data Healign x Curve Parameter 8 30 deg t Linear f Lag Paints LMS 4 1 User Manual Harz La Limit 552 10 1514 40 0000K Cancel Help Processing Menu 7 12 Data Realign P E E ES AMHR DAB Dp The Processing Data Realign menu item will open a dialog whi
179. etas 1 1 tracking bandpass filters when making SPL measure ments which ensures maximum noise rejection This greatly reduces the effective noise floor by as much as 30 40 dB Bandreject Filter The bandreject filters have a sharp attenuating characteristic shown by a single bandreject filter These filters have a depth of typically 40dB attenuation at the center When used in sweeps misalignment between the Osc frequency and the Filter notch frequency will limit this attenuation depth to between 30 40dB By combining both filters as bandreject a notch with a depth of 60 80dB can be produced for quasi distortion measurements gt dBm Voltage Measurement lt Phase gt ap 20 100 Highpass Filter The Highpass filter also has a rolloff rate of 12 dB Octave 2nd order Setting both Meter Filters as Highpass filters results in a 24 dB Octave 4th order slope rate Highpass filters are typically used to restrict the low frequency range of the system LMS 4 1 User Manual Lowpass Filter The Lowpass filter has a rolloff rate of 12 dB octave 2nd order as shown in the graph Notice the rolloff knee has a flat characteristic up to the corner fre quency of the filter Setting both Meter Filters as Lowpass filters results in 24 dB Octave 4th order attenuation Lowpass filters are typically used to limit the u
180. example of a typical parameter set generated for the LEAP model The input curves are shown in Blue and the model simulation curves are shown in Red The resulting parameters are Vab 2 07 cu Ft Revc 1 62 Ohms Fo 22 1 Hz Sd 0 034 sqM Krm 6 55 mOhm Kxm 32 9 mOhm Erm 0 750 Exm 0 629 Mmd 43 g Mms 46 7 g BL 5 35 TM No 0 5 SPLo 89 2 dB Cms 1112 uM N Vas 6 45 cuFt Qms 7 38 Qes 0 366 0 349 141 Processing Menu Chapter 7 A simulation is produced for both the reference and delta curves The simulation curves show a close match to the original data for both the reference and delta curves This result is fairly typical for most loudspeakers These parameters were generated for the LEAP model Speaker Parameters Metho Single Curve Elec Motor Single Curve Elec System Single Curve with Mmd Double Curve Delta Mass t Double Curve Delta Comp Model Parameters Data Transfer Input Parameter Reference Curve 11 Hwi12 a 1 62 Freq mp Phase Delta Curve 12 abx 2 0697 Freq mp Phase f Free Ai Ohm Sd sgh Yab curt Inf Baffle 1 620 34 000m 2 070 j 50 000 Standard LEAP Reve Mmd Kg Levc Mme Gms TM 1 620 43 099m 32 838m 46 704 7 383 Er Krm Ohm Ohm Cms Hz E 6 553m 32 899 1 112m mem E 0 500
181. f this license or as otherwise authorized by law is an infringement of the copyright Bi Limited Non Exclusive License You may a use the enclosed program on a single computer b physically transfer the program from one computer to another provided that the program is used on only one computer at a time and that you remove any copies of the program from the computer from which the program is being transferred c make copies of the program solely for backup or archival purposes You must reproduce and include the copyright notice and label any backup copy You may not a distribute copies of the program or the documentation to others b lease rent grant sublicenses or other rights to the program c provide use of the program in a computer service business network time sharing multiple CPU or multiple users arrangement without the prior written consent of LinearX d translate or otherwise alter the program or related documentation without the prior written consent of LinearX Terms Your license to use the program and the documentation will automatically terminate if you fail to comply with the terms of this agreement Your license terminates in the event that you receive a license for an updated version of the product that replaces this product If a license expiration date is printed on your documentation or provided through other means such as a time limited electronic or software key your license expires on the day as shown in t
182. ght vertical parameter In most cases the Left data represents the magnitude of a given response and the Right represents the phase of that response However it is possible to construct curves which contain a different pair of vertical data arrays using this dialog Probably the most common example of this is an SPL Ztype curve entry In this case the Left vertical data contains the SPL magnitude and the Right vertical data contains the Impedance magnitude This Data Transfer operation moves a single vertical data array from one curve entry to another The vertical data can be from either the Left or Right arrays and can be transferred to either the Left or Right arrays of the Result curve entry The curve list boxes provide selection of the library curve for the operations These special list boxes shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Freg SPL Phase The example on the following page shows a normal SPL curve graph an impedance curve graph and the resulting SPL Z combination curve graph If you are going to be working with double magnitude curves such as the type just described you will probably need to enable the Auto Up Dn Right Vertical Data item in the File Preferences dialog In order for the right data to respond to scaling commands this feature must be enabled Otherwise only t
183. graph for the currently displayed units The shortcut key FS or the tool button as shown above on the Scale toolbar can also be used to activate this item This feature 1s heavily utilized The Auto scale function analyzes the currently displayed library curves and determines the required Max Min range parameters to display the highest levels of any curve This function is commonly used to quickly bring the curves into view The Left Vertical scale is always controlled by this function However control of the Right Vertical is optional depending on the setting of Auto Up Dn Right Vertical Data in File Preferences 213 Scale Menu Chapter 9 214 LMS 4 1 User Manual Chapter 9 Scale Menu 9 3 Up Parameters Fe Auto F8 Down The Scale Up menu item will increase the vertical scale range for the currently displayed scale units The tool button as shown above on the Scale toolbar can also be used to activate this item This feature is heavily utilized The Scale Up function instantly increases the display range For dB scales the Max Min ranges are increased by the value per division For fixed scales the range is increased to the next appropriate increment Note Increasing the scale moves curves down The Left Vertical scale is always controlled by this function However control of the Right Vertical is optional depending on the setting of Auto Up Dn Right Vertical Data in File Preferences LMS 4 1 215 User M
184. gure below 281 SPL Applications 282 Chapter 14 14 4 Half Space Measurements Half space or pit measurements are made by recessing the loudspeaker in the ground with the drivers facing toward the sky and the microphone placed above the enclosure Again the mic should be directly in line above the high frequency driver This is shown in the figure below Since this type of measurement places the baffle board of the enclosure in an infinitely large plane measurements made in half space do not exhibit the rising response that occurs with anechoic or ground plane measurements However like the ground plane the radiation field is half of a full sphere so the level is 6dB higher than a free field or anechoic measurement As with ground plane measurements there should be no obstructions for a 15 30 foot radius around the area for low frequency work Pit measurements can be one of the very best for producing SPL response curves of the transducer enclosure free of any reflection defects caused by the environment Many loudspeaker researchers and manufacturers have em ployed this method for years In some cases the size of the plane can be reduced If mid and high frequency response plots are required a smaller plane is permissible A plywood table 8 feet square with a hole cut in the center for the transducer would provide good results down to about 200Hz The table can be above the floor and will act as an infinite plane at the
185. ham ber or placement of the speaker in mid air far from any surfaces The only surface is that of the baffle board of the enclosure This method includes the enclosure diffraction effects The purpose of an anechoic chamber is to absorb all sound striking the walls so that none is reflected This is typically handled by covering the walls of a room with sound absorbing materials A chamber is shown below However even well designed chambers still do not approach the ideal anechoic behavior at low frequencies At low frequencies total absorption is extremely difficult to achieve For this reason most chambers degenerate to the behavior of a constant pressure enclosure as frequency is decreased At these frequencies the pressure field will cause arise in level with decreasing frequency typically 12dB Octave In the mid and high frequencies the chamber will usually have good anechoic characteristics Given the difficulty of either building an anechoic chamber or dealing with microphones and loudspeakers suspended high in mid air true anechoic measurements are not convenient for most people SVT TT PANNE 2 gt gt mx 2 3 DAAAAAAAAAX LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications 14 3 Ground Plane Measurements Ground plane measurements are very nearly identical to anechoic measurements Because the measurement includes both the direct sound from the enclosure plus the mirrored image from the gro
186. hapter 4 4 10 Editor E Ctrl M id E Oper BpauuSUJiSsSsse Reopen k Str FS Gaves Revert The File Editor menu item allows you to open and view edit a file with your currently selected text editor The tool button as shown above can also be used to activate this item Load QuickSet File Save Duick Set File Print Ctrl F Preferences The default editor is set to NOTEPAD EXE However you can easily change this to your favorite text editor through the File Preferences dialog Exit Ctrl There are many occasions in the program where you may wish to view or edit the contents of a text file This arises frequently when you are importing exporting text data All text files exported by the program have the default extension TXT File Editor presents a dialog to choose the file to open with the editor Select File to open with Text Editor Look in Set a Expnaise set Mkmicall set a set la Flatbpit set Mkrnical2 set set la Flatbpit2 set Mace set Meweimp set Spl et Flatnafl set la Mac3 set Polri k set la gate s Inductor set la Miccall set Fite set S ustest sel la Initiliz set la Miccal2 set la Rub Test set El File name Files of type ai Files Cancel LMS 4 1 User Manual Chapter 4 LMS 4 1 User Manual File Edit Search
187. he Left scale will be controlled 147 Processing Menu Chapter 7 SPL vs Fre 180 5 i BEBO OBS E 148 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Realign Curve Averaging Curve Compare Processing Menu 7 11 Data Splice P E E ES AMM GENE ES amp The Processing Data Splice menu item will open a dialog that allows you to move individual vertical data arrays from one curve to another The tool button as shown above on the Processing toolbar can also be used to activate this item A splicing frequency is chosen by the user for which data below this frequency will come from one curve and data above the frequency will come from the second curve This can be very useful for combining two curves taken under different conditions into a final result curve One common example is combining near field measurements to cover the low frequency region with gated
188. he Number 1 Repeat X 140 IF X 1 GOTO 50 150 LOADOS MACZSET 160 DATACURVE 20 170 GRPHCURVE 11 12 13 14 180 LOADLIB DEVELOP LIB 190 PAUSE Hit Any Key to Statt Sweeps o s d 200 SWEEP 300 END 256 LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs 13 5 Debugging and Error Reporting As with any type of programming bugs are sure to occur This can mean that the program will not do initially what you had wanted it to or that you will simply receive error messages when you load the program and processing begins If the program runs without error messages then it will be easy to see if the program is doing what you wanted it to and what adjustments to the existing statements or if additional statements are required This might typically be that you will need to clear the work area before writing the next messages or that you wanted to display the graph at a certain time These types of programming errors are usually easy to fix since you can see directly what the problem is and what needs to be done to correct it If error messages occur then LMS will abort the macro s execution This typically occurs when keywords for commands cannot be recognized When an error is detected it will usually be reported to the screen on the command line The line number where the error occurred will also be reported to the work area as well If you are creating the macro using the Macro Editor you can take advantage
189. he README MAC file in the LMS MAC folder for any other possible new macros or updated information LMS 4 1 User Manual Chapter 13 Macro Programs 13 9 Macro Run Dialog When a macro is started the Macro Run dialog appears in the upper left hand corner over the graph This dialog can be manually rolled up down and will also automatically roll up during a sweep This is helpful for viewing the entire graph To terminate the macro use the ESC key or the Abort button If a sweep is in progress you will need to use ESC or F9 to first terminate the sweep At the top of the dialog is the Line panel The text of the currently executing macro line is shown here The large viewing area below is the work area This region can be used to post multiple messages from the macro Itis useful for creating menus Below this region is the command line The macro program can display special single line text messages here At the bottom of the dialog is the Parameters panel The edit box is used to enter data during macro operation and the Ok button is used when your editing is finished The Ok button can also be used in place of pressing the ENTER key or SPACEBAR for various command prompts The last panel in the lower right corner contains two status indicators PASS FAIL and the Abort macro button Macro Running Test ESC to Abort Lin 270 INPUT Enter Menu Selection Number 1 3 lt Work Are Test Program for Macro De
190. he documen tation or on the day that the electronic or software key expires If this license is terminated you agree to destroy all copies of the program and documentation Limited Warranty LinearX warrants to the original licensee that the disk s and or electronic key s on which the program is recorded will be free from defects in materials and workmanship under normal use for a period of ninety 90 days from the date of purchase as evidenced by a copy of your receipt If failure of the product components has resulted from accident abuse or misapplication of the product then LinearX or third party licensors shall have no responsibility to replace the disk s or key s under this limited warranty This limited warranty and right of replacement is in lieu of and you hereby waive any and all other warranties both expressed and implied including but not limited to warranties of merchantability and fitness for a particular purpose The liability of LinearX or third party licensors pursuant to this limited warranty shall be limited to the replacement of the defective disk s or key s and in no event shall LinearX or third party licensors be liable for incidental indirect punitive or consequential damages including but not limited to loss of use loss of profits loss of data or data being rendered inaccurate or losses sustained by third parties even if LinearX or third party licensors have been advised of the possibility of such damages This
191. he graphs The amount of text which can be entered depends on the size of font currently selected Title Block Data There are three fields provided to enter a company name personal name and project name The fields could also be used for other types of record keeping data The fields will appear in the title block of all graphs Notes amp Comments Left Page Right Page Automatic Curve Info Notes line 1 GPATIPakinglot i992 2 Line 4 25Ft18Ga Twisted Par Title Black Person Company Praject Cancel Help 75 Graph Menu Chapter 5 76 LMS 4 1 User Manual Chapter 6 Analyzer Menu Analyzer Menu 6 Analyzer Parameters F5 Reo amp a ta ets fi Sweep sc On Off F10 ALC Meter Microphone Setup Interface Macro Aun Calibration LMS 4 1 77 User Manual Analyzer Menu Chapter 6 78 LMS 4 1 User Manual Chapter 6 LMS 4 1 User Manual Analyzer Menu 6 1 Parameters Parameters 5 BOOBZ Sweep Start Stop Osc Or Dff F10 ALC Meter The Analyzer Parameters menu item will open a modeless dialog which controls all of the interaction with the LMS analyzer hardware The tool button as shown above can also be used to activate this item or the shortcut key F5 Selecting the menu item tool button or shortcut key again will toggle this
192. he upper left corner of the window 223 View Menu Chapter 10 224 LMS 4 1 User Manual Chapter 10 View Menu 10 3 Redraw Zoomin Zoom Out Shift Sub lt oom 1 Shift F1 doom zx Shift F2 lt oom gs Shift F4 Zoom es Shift F8 Redraw Ctrl H The View Redraw menu items will redraw the graph window The tool button as shown above on the View toolbar can also be used to activate this item or the shortcut key Ctrl R The Redraw function is frequently called by other internal functions in the program Under normal conditions the graph window is redrawn as required automatically However this function can be used to redraw the window manually if needed LMS 4 1 225 User Manual View Menu Chapter 10 226 LMS 4 1 User Manual Chapter 11 Toolbars Menu Toolbars Menu 11 Toolbars Show All Hide All v File wv Graph w Analyzer Processing Utilities wv Scale ToolBox LMS 4 1 22 User Manual Toolbars Menu Chapter 11 228 LMS 4 1 User Manual Chapter 11 LMS 4 1 User Manual Toolbars Menu 11 1 Show All Help Hide All v File w Graph w Analyzer v Processing w Utilities Scale wv Toolbox The Toolbars Show All menu item will display all of the toolbars and the Toolbox Toolbars can appear in any of four locations the top control bar the bottom control bar the Toolbox or as single floating windows The location of
193. his command Example 100 PRINT B PRINTCN Print Graph This command now behaves the same as PRINT for LMS version 4 Spooling a file to disk is now under the control of the Windows system and printer driver Example 100 PRINTCN LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs B PRINTFN Print Graph This command now behaves the same as PRINT for LMS version 4 Spooling a file to disk is now under the control of the Windows system and printer driver Example 100 PRINTFN B PRINTVN variable Print Graph This command now behaves the same as PRINT for LMS version 4 Spooling a file to disk is now under the control of the Windows system and printer driver Example 100 PRINTVN X PRNPORT xxxx Port LPTI LPT2 LPT3 COMI COM2 COM3 This command selects the port to be used with the PRINTSTR command If a serial port 1s chosen the existing setup from the Windows control panel is used Example 100 PRNPORT LPTI PULSE Produces a Trigger Pulse The PULSE keyword is used to produce a trigger pulse at pin 13 of the DBISF connector Normally this pin is low When this command is executed pin 13 will go high for the amount of time specified in the File Preferences dialog and then return low This is a TTL level pulse This can be used to activate some other external equipment such as a turn table for polar plotting or perhaps to activate relays that control test hook up connections Example
194. his dialog supports an extensive variety of both vector and raster image formats There are many different kinds of graphics applications The type of file format to use depends entirely on the application Generally you will be opening or placing the file in some other application program Obviously a file format must be chosen which is supported by the other program The import capabilities of most programs are constantly changing with each revision so it is impossible to give any general recommendations here Please consult the documentation of the other program If your primary application is to embed the images as part of a word processing document then the EMF WMF and EPS formats are most commonly supported However using the EPS format generally requires printing to a PostScript printer to obtain the full resolution For non PostScript printing use EMF or WMF formats If your primary application is for graphical editing where you wish to modify the graphics content you will need to choose a format that your drawing or illustration program supports This could be any of the formats Please consult the documen tation of the other drawing illustration program Artwork The name of the graph is shown here as the title above the grid on the graph Format When Raster is selected the format resolution color and compression controls will be active Theraster image data will also be displayed in the fields at the bottom of the panel Whe
195. hm limit at about 16kHz Between these limits the inductance value remains very constant Similar results are also seen for the 5mH powdered iron choke Both of these inductors show very good performance Inductance vs Fre Et opin 1000 Ohms pd ER LE qeu S SEE Edu Mmm lace c qme EN EX Es Examples of Inductor Value Sweeps LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications The 4mH bar choke shows a very pronounced slope to the curve between 100Hz and 10kHz The value is clearly falling as frequency increases This is due to the iron lamination construction which has strong frequency dependent characteristics At higher frequencies the inductance falls and the internal losses in the iron lamina tions rapidly increase The two air core chokes show larger coil resistance per mH and also show a significant amount of drop at high frequencies Air core inductors require a much higher number of turns which increases the winding capacitance and skin effect in the coil Viewing these curves the iron powder bobbin inductors show the least amount of parasitic effects resistance capacitance frequency coefficient and maintain their desired inductive nature over the widest range of frequency 349 Misc Applications Chapter 16 350 LMS 4 1 User Manual Appendix Appe
196. ialog different parameters can be updated from library files or retained as global settings across library files Note By default the program always loads your last library when it is first started Open Library File Look ir EJ Lib File name Test lib Files of type Library Files lib Cancel LMS 4 1 User Manual Chapter 4 LMS 4 1 User Manual File Menu 4 3 Reopen The File Reopen menu item opens an existing library by one of the previously stored 12 paths The sub menu adjacent to the drop down menu displays the possible choices These paths are updated based on your previously opened library files The tool button shown above can also be used which will present a dialog with the same path choices as shown below Each path 1s listed on a button for selection If your existing library has changes and has not yet been saved you will be prompted to save it first Reopen Library 49 File Menu 50 4 4 Save Ctri M Open Ctrl Reopen Save Gaves Revert Load QuickSet File Save Huck Set File Print Ctrl F Editor Preferences Exit Ctrl Chapter 4 File B g CS EE SU IB S ze The File Save menu item saves an existing library The accelerator key CTRL S can be used to activate this item using the keyboard or the tool button as shown above If your library has not yet been named you will be prompted to provide
197. ible signal Meter x Measuremen Test Resistance t Ohm 4 Frequency Hz Inductance 10 0000 200 0000 Capacitance Impedance C hm Resistance Ohm Frequency Hz Limit T estin Value Value Enable 1 0000 10 0000 LMS 4 1 91 User Manual Analyzer Menu 92 Chapter 6 Measurement This radio group selects the type of measurement resistance inductance or capacitance Depending on the selection the type of units in the Data display panel will change Other parameters in the dialog are also changed based on the type of measurement Test At Using this panel you can choose whether to conduct the test at a specific frequency or a specific impedance For resistance measurements only the frequency method is relevant For Inductance and Capacitance testing at a specific impedance will cause the oscillator frequency to automatically change until the appropriate frequency is found that produces the desired impedance The test impedance must be attainable within the 10Hz 100KHz range or the analyzer will not reach the desired impedance but will reach one of these frequency limits Data Three readouts are shown on this panel Impedance Value and Frequency The center Value field will change to a specific type of units based on the selected measurement The colors of these displays can be changed by clicking on them with the mouse The color wil
198. ides selection of the library curve for the save load This special list box shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry An example of a normalized microphone response curve Ratio vs Freq 80 LT 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 197 Utilities Menu 198 An example of an MDF file listing is given below MDF Microphone Data Format File Author LinearX Systems Inc Date Jun 23 2000 Fri 12 35 am Model M51 Serial 123456 dBspl 94 000 dBm 38 898 Points 300 Index Freq Hz dB Deg 1 10 000 2 59 0 00 2 10 281 2 58 0 00 3 10 570 2 57 0 00 4 10 868 2 55 0 00 5 11 173 2 54 0 00 6 11 488 2 51 0 00 7 11 811 2 47 0 00 8 12 143 2 43 0 00 9 12 485 2 40 0 00 10 12 836 2 37 0 00 11 13 197 2 33 0 00 12 13 568 2 29 0 00 291 31162 822 4 01 0 00 292 32039 357 4 15 0 00 293 32940 547 4 20 0 00 294 33867 086 4 16 0 00 295 34819 688 4 04 0 00 296 35799 082 3 81 0 00 297 36806 023 3 68 0 00 298 37841 289 3 51 0 00 299 38905 676 3 34 0 00 300 40000 000 3 16 0 00 End Chapter 8 LMS 4 1 User Manual Chapter 8 Utilities Menu 8 9 Polar Convertor B D ER ES Import Curve Data File Export Curve Data File ES Export Graphics to File Export Graphics to Clipboard
199. ilities Menu Chapter 8 Message x Node 12 of 50 139 005436 Values 476 504534u Question Information Clicking on the small square panel in the upper left corner of the graph activates a query function The cursor will be changed to a question mark When you then click on an object in the graph or an empty area of the graph itself a message box will then display information about the object An example is shown above Different kinds of information will be displayed depending on the type of object selected Drag Scrolling If you hold down the Shift key on the keyboard while clicking and moving with the left mouse button the graph page will be dragged across the screen The drag cursor will appear as shown here on the left Guidelines Guidelines can be pulled out of the rulers in the normal fashion Move the mouse cursor over a ruler and then click and hold the left mouse button The guideline can then be dragged out of the ruler on to the graph Guidelines can be repositioned at any time by dragging and can be removed by dragging them back into the rulers 188 LMS 4 1 User Manual Chapter 8 Utilities Menu Node Editing Before a node can be moved it must first be selected When a node is selected its color changes from Gray to Red In order to select a single node the cursor must be moved within the capture range of the node When the cursor is in the capture range it will change from the arr
200. imental Depending on the type of device environment and other factors one method may prove to be superior over another This is very much a trial and error investigation While many methods have basically sought to measure SPL acoustic levels the same function of the test can also be accomplished electrically Based on prelimi nary testing already carried out with the LMS system equivalent results were obtained to those that measure SPL In fact for many of the samples tested this electrical method proved to be more sensitive and reliable The basic idea here is to measure aberrations rub buzz noise in the electrical system by measuring the voltage across the transducer under current source drive conditions Any aberrations present in the acoustic system should also be reflected and therefore present in the electrical side This method also seems to be more tolerant of ambient noise and typically did not require any special enclosure If high levels of external noise are expected an isolation box should be used The basic hookup is very simple and is identical to that of measuring direct impedance The LMS OSC output is tied to the transducer terminals just like an impedance test The Analyzer Parameters should be set to measure Voltage with the Line Output selected for the meter The filters must both be changed from FLAT to BandReject The tracking ratios must also be 1 1 with tracking ON Unlike the acoustical R B test the e
201. ing measured are strong with good signal to noise ratio then these parameters can probably be adjusted without much difficulty 341 Misc Applications 342 Chapter 16 The best way to determine these parameters is to run your tests with the normal default values Then try changing some or all of these values to increase the speed and note whether or not the accuracy or consistency of the data is affected LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications 16 7 Measuring Inductors amp Capacitors vs Freq Another capability in the LMS software is the direct measurement and automatic computation of fundamental parameters such as inductance and capacitance The user now has the capability of actually measuring a component s value over a frequency range and therefore gain an idea of the nature of the component s frequency dependent characteristics There are two DATA TYPE modes selectable in the Analyzer Parameters for INDUCTANCE and CAPACITANCE An example for capacitance is shown below The basic setup is the same as for measuring impedance the component to be tested is directly connected to the leads of the LMS output All other parameter settings on the control panel are basically the same as for impedance measurement The output level should be set to maximum This will produce a testing level of about 10mA through the component LMS is a single port system and cannot measure true phase to separate
202. ion All Line Numbers keywords and parameters must be separated delimited by space characters between them Spaces should not be placed between the digits or signs of numeric parameters At the end of this chapter there is a summary listing of all Macro Keyword Commands This listing includes a brief description of the use of each command Comment The asterick keyword is used to denote a comment on a line A comment line can be placed anywhere in the program It is used to provide information for the reader or programmer Example 100 This is a comment line B ADD entrynumA entrynumB entrynumR ADD A B R The ADD keyword is used to produce a summation result curve from two other curves All parameters must be integers and between 1 through 50 This 1s the equivalent of adding the curves Example 100 ADD 11 12 15 B COMLCLR Command Line Clear The COMLCLR keyword is used to clear the command line If an old message is no longer desired on the command line then use this command to erase it Example 100 COMLCLR 259 Macro Programs 260 Chapter 13 COMLMSG message Command Line Message COMLMSG keyword is used to write a message on the command line This could be used to tell the operator something to do or to notify the operator of something The message parameter should be in double quotes The command line is always automatically cleared before placing the message You do not have to use
203. ion 4 speaker 137 Speaker Parameters 131 315 SPL 84 SPL Measurement 35 SPL Z 147 Splash Screen 61 SQRT 269 square 109 square root 109 Static measurements 40 Status Bar 235 Step response 127 SUB 270 suffix 23 sum the drivers together 297 SWEEP 270 sweep 79 Sweep Panel 86 Sweep Start Stop 37 89 Syntax Check 194 syntax highlighting 193 SYSCONFIG TXT liv 249 Tail Correction 145 Technical Support liv Tel liv text file 59 text file data 163 texture patterns 62 TIF 168 time domain 126 Title Block Data 75 Tool Bars 17 Tool Buttons 17 Toolbars 229 ToolBox 237 Toolbox 229 231 Tracking 82 Tracking Cursor 18 tracking cursor 61 tray 231 237 trays 17 True Type 3 TrueType 28 171 TTL pulse width 63 TypeColor 29 TypeFace 29 TypeSize 29 TypeStyle 29 U Unary Math Operations 105 Underline 67 undo redo 193 Units 164 units button 80 Units SI 353 URL 249 LMS 4 1 User Manual Index V WORKCLR 271 WORKMSG 271 VARLABEL 270 Vas 137 X vector and raster image formats 167 Vector AVE 154 XLR 35 Vector Images 169 Z Vector RMS 154 vertical data arrays 147 ZCURVEFO 271 Vertical Scales 207 211 ZCURVEZO 271 vertical scales 44 Zimp2Wire 307 VGA 26 Zimp4Wire 307 VI Box 41 310 Zoom 19 video resolution 3 Zoom IX 2X 4X 8X 223 voice coil resistance 137 Zoom In Zoom Out 221 voltage divider 41 zoom level 221 Volts 84 W WAIT 270 walls or boundaries 279 Web Win2000 3 Win32 3 253
204. is to examine the nonlinear characteristics of the drivers This can be accomplished by running several sweeps at different drive levels For example one may want to run curves at 1 10W IW 10W and 100W In this method a power amplifier is required Also some means to measure the current flow ing through the speaker as well as the voltage across the speaker must be devised The VI Box is ideally suited for this purpose This device already contains all of the neces sary components to perform constant voltage measurements The hookup is shown here This method does not directly measure impedance but in effect measures the inverse admittance However using the DIV and SCALE utilities in LMS we can conveniently invert this over into impedance properly scaled You will need to measure both the current through the speaker and the drive voltage at the speaker terminals The LMS Line Input can be alternately plugged into the VI Box Voltage and Current outputs to measure the two different quantities The basic relationship that will be used is Z The impedance can be found from the voltage across the speaker and current flowing Voltage amp Current Measurement Interface current through the speaker LINEAR LinearX Systems Inc 9500 SW Tualatin Sherwood BLK Portland OR 97062 8586 USA in USA 1V 100A 25A max 1V 100V 40dB SPEAKER VOLTAGE V OUTPUT jOmr
205. itance simply by connecting the component directly to the LMS oscillator output and using the appropriate test mode However the RLC Meter works differently than true RLC bridges Since LMS is asingle input analyzer it does not have the ability to measure true phase at a single frequency in order to separate the resistance and reactance values from the total impedance However it does have the ability to change the test frequency to a suitable range where the component is mainly reactive Knowing the reactance and test frequency the RLC Meter can then calculate and display the fundamental component value To permit automatic selection of the test frequency the utility allows the user to specify the impedance at which to test the component The meter is set by the user to find a specific impedance value and then sweeps the oscillator frequency until it locates the frequency at which the component has that impedance Once it locates the correct frequency it then displays the L or C value of the component at that frequency For testing resistors this automatic mode 15 not used The meter can also be set to a manual mode where the user can fix the test frequency at any value and the meter simply displays the component s value at that frequency For QC testing of like components the meter is also equipped with maximum and minimum test limits which can be set by the user A valuefalling within the limits will produce a visible message and aud
206. items will change the display scale factor on the graph window The tool buttons as shown above on the View toolbar can also be used to activate these items or the shortcut keys Shift Add and Shift Sub The shortcut keys Add Sub are the keys in the numeric keypad Each zoom operation increases or decreases the scale factor by 115 The maximum zoom level is 800 The current zoom level is displayed in the Status Bar located at the bottom of the window The center position of the graph will be maintained during zoom changes 221 View Menu Chapter 10 222 LMS 4 1 User Manual Chapter 10 LMS 4 1 User Manual View Menu 10 2 Zoom 1X 2X 4X 8X Zoomin Shift 4dd Zoom Out Shift Sub E 1 5 25 15 5 H oom amp Shift F8 Ctrl F The View Zoom 1X 2X AX 8X menu items will change the display scale factor on the graph window The tool buttons as shown above on the View toolbar can also be used to activate these items the shortcut keys Shift F1 Shift F2 Shift F4 and Shift F6 Each zoom operation forces the scale factor to a preset value of 100 200 400 or 800 respectively The maximum zoom level is 800 The current zoom level is displayed in the Status Bar located at the bottom of the window The center position of the graph will be maintained during zoom changes However when the 10096 zoom level is selected the graph alignment will be reset to t
207. ity to directly change any of the parameters individually However this individual control can some times be tedious It is possible to save the entire contents of all the analyzer parameters at once as a file and then this file can be reloaded later to restore all of the parameters together These files are known as QuickSet files These files contain a snapshot of the entire analyzer parameters dialog A number of QuickSet files have been included with the program for some common setups QuickSet files can be used to save and load your common test setups very quickly This eliminates the need to reset all of the individual parameters To save load a QuickSet file you must first go to the File Menu and then choose Load or Save QuickSet File There is a folder under the LMS directory tree named Set This is the default folder for QuickSet files however you can locate the files anywhere you wish When a QuickSet file is loaded all analyzer parameters are set to those recorded in the QuickSet file The Data Curve entry is also stored recalled with a QuickSet file The Data Curve 15 the single curve in the curve library where the next sweep data will be placed However any number of curves can be displayed on the graph simultaneously provided they have the same type of data A curve library can hold 50 curves Open Set File Look in CX Set 3 Maci set 3 zimp set B Mac3 set la Spg set 3 Polrlk set Test set D
208. k tests through the cables When the tests have been completed you will be notified of any failures LMS 4 1 User Manual 101 Analyzer Menu Chapter 6 102 LMS 4 1 User Manual Chapter 7 Processing Menu Processing Menu 7 Fal E ES ES B 95 Gs m sl ES x Processing Una Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Fast Fourier Transform Fast Fourier Transform Speaker Parameters T ail Correction Data Transter Data Splice Data Realign Curve Averaging Curve Compare LMS 4 1 103 User Manual Processing Menu Chapter 7 104 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Curve Averaging Curve Compare LMS 4 1 User Manual Processing Menu 7 1 Unary Math Operations PE RR E3 Reb lud DAB AE The Processing Unary Math Operations menu item will open a dialog which performs mathematical operations on a single curve The tool button as shown above on the Processing toolbar can also be used to activate this item Unary math operations involve only a single curve hence the term unary The result of the operation is returned in the same curve entry
209. l be added to the array The array is auto incrementing and when a color is added it will be assigned to the next pad These colors will persist as long as the program is running Clicking on one of the color pads will select the color Selection These two pads display the current and original colors This allows you to compare the two orto return to the original if desired Clicking on the Original Color pad will make it the current color Add Custom Button Clicking this button will add the current color to the Custom Colors array The array is auto incremented so the next color pad will be used Model and Parameters There are three color model choices Hue Saturation Value HS V Red Green Blue RGB Cyan Magenta Yellow CMY The model selection controls which set of parameters appear on the sliders The Hue slider has a range of 0 degrees to 360 degrees This is the Hue of color as specified radially around the HSV wheel other sliders range from 0 to 100 LMS 4 1 User Manual Chapter 2 LMS 4 1 User Manual General Features HSV Color Space The large circle or color wheel in the center of the panel enables live color editing by use of the mouse While holding down the left mouse button drag across the wheel and the color at the point of the mouse is selected If you go into the black region the last color at the edge is kept until you reenter the circle The color wheel represents the polar coordinates of H
210. l be rotated through a preset list Limit Testing This panel provides the capability to test components in a repetitive QC pass fail manner When the component is connected the value is compared between the limits A message will appear to reflect the pass fail condition If you do not wish limit testing uncheck the Enable check box Output To begin the testing click this button To stop the testing click it again Units amp Accuracy The center parameter reads out the value of the component The units will be either Ohms milli Henries or micro Farads The RLC Meter 1s suitable for measuring resistor values from 1 500 Ohms inductors from 0 01 mH 1000mH and capacitors from 0 01uF 1000uF Worst case accuracy is about 5 but typical accuracy can be expected around 2 It is important to remember that many components will have values which change by 1046 or more across the audio frequency range This renders high precision single value identification of the component much less useful LMS 4 1 User Manual Chapter 6 LMS 4 1 User Manual Analyzer Menu Starting the RLC Meter When you first select the RLC Meter from the menu the meter will be initially turned off This is to prevent possible damage to transducers if the LMS output is still connected to a power amp when the dialog is first opened When the meter is turned on an output voltage of about 5 Vrms is produced Note Make sure that the LMS output cable is disconn
211. l reflections two methods can be employed 1 setup the environment so as not to produce any significant reflections or 2 use gating to remove reflections When making ungated SPL measurements any environmental boundaries such as walls or other reflecting surfaces will produce multi path echos which will be added into the response measurement These reflections will produce narrow peaks and dips in the response curve that are not actually there in the transducer itself As such these measurements are domain critical if the goal of the measurement is to analyze only the loudspeaker and not the room plus the loudspeaker There are several types of environments which can be set up which will eliminate at least to a large degree any multi path reflections caused by walls or boundaries In fact these methods are really the only ones which can be used when running full range frequency response curves down to low frequencies Gating is effective at mid and high frequencies but still does not solve the problem of low frequency measurement Ungated SPL measurements can be successfully carried out in several types of environments These are anechoic chamber ground plane half space and near field The following pages should help to explain the significant characteristics of these methods 279 SPL Applications 280 Chapter 14 14 2 Anechoic Chamber Measurements Anechoic measurements require either a specially constructed anechoic c
212. le OO Oo 00000000 OO Oo 00000000 333 Misc Applications Chapter 16 Import the Data into LMS With the files now created they can be imported into LMS The data files can then be Imported into LMS library curve entries The type of data here is dB volts but it could be any other type of units as well The final results are shown on the following page as complete full curves If you were not happy with the first curves created you could now go back to the original ASCII data files and adjust whatever values are required Then re Import the files again into the same LMS Curve Library entries and they will be overwritten Manual Data for LMS January 19 1991 Author C Strahm Min Limit Curves for Passive Network Test Datapoints 10 dB Levels Freq Hz Level dB Phase deg 10 5 2 0 0 25 2 50 0 100 6 200 10 400 10 500 13 650 16 850 23 1500 34 End of File O Min Limit Data File 334 LMS 4 1 User Manual Misc Applications Chapter 16 a 8 8 8 s s sg 8 3 g S 3 68 gt e a 1 a o a Voltage vs Freg LO 5 42 No N Eo Misc Applications Chapter 16 336 LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications 16 5 Modifying the Mic Calibration Curve The mic calibration MDF file contains a curve which is the response of the measure
213. le resources permit you will receive an error message or your system may lock up Not all of the raster formats support all of the different color and compression options Also some formats do not store the DPI information for absolute scaling If one format does not work for your application just try another Vector Images Vector images are mathematical formula representations of the artwork They contain coordinates and special commands unique to each format They can be both color or black amp white The resolution of the image is virtually infinite and will print with the full resolution of the final printing device While vector images are sometimes a less portable form of graphic representation they are extremely efficient and provide the highest quality resolution The following industry standard vector formats are supported WME Windows Metafile Standard WME Windows Metafile Placeable EMF Windows Enhanced Metafile E FPS EncapPostScript B amp W amp TIF 5 EncapPostScript CMYK amp TIF B AI Adobe Illustrator Format PDF Acrobat Portable Document Format 169 Utilities Menu 170 Chapter 8 Fonts When dealing with vector formats the issue of fonts becomes very important If the file you are producing will only be used on your computer system then the font issue is somewhat irrelevant However if the generated files are to be viewed on other computers then you must choose fonts for your designs whi
214. lectrical test described here seems to work best witha BANDREJECT 1 1 filter setup rather than a HIGHPASS 7 1 While this will allow the sweep to pick up low order harmonics like the 2nd and 3rd the drive level is quite low so that basic transducer nonlinearity does not seem to interfere The graphs on the following page show some typical results of tests run on tweeters and midranges These examples show a 15dB to 30dB hump for a bad device 327 Chapter 16 Misc Applications Voltage vs Fre Midrange Units Tested for Rub Buzz Voltage vs Fre Tweeter Units Tested for Rub Buzz LMS 4 1 User Manual 328 Chapter 16 LMS 4 1 User Manual Misc Applications The curves shown in the top graph of the next page are of two woofers The good woofer has a small rise in the response near 20Hz This is due to nonlinear distortion present in the working unit However the bad unit does not have this rise There are some small humps near 300Hz but nothing that significantly stands out as bad If the filters on the analyzer parameters are now changed back to FLAT and another pair of sweeps run curves similar to impedance can be produced This was done on the two woofers and is shown on the lower graph of the next page Here the good woofer shows the typical resonance rise The bad woofer shows no resonance at all This is now a very significant defect and easy to catch This underscores the point that no one test can catch all
215. licking the Estimate Optimize Simulate button an estimate of the param eters is derived from the input data and then optimized for best fit The simulation curve is then placed into the specified library curve entry The following page shows an example of a typical parameter set generated for the LEAP model The input curve is shown in Blue and the model simulation is shown in Red The resulting parameters are Mmd known to be 56 g Revc 3 12 Ohms Fo 37 8 Hz Sd 0 0856 sqM Krm 4 58 mOhm Kxm 10 7 mOhm Erm 0 700 Exm 0 690 Mmd 56g Mms 70 4 g BL 11 38 TM No 3 4 SPLo 97 3 dB Cms 252 uM N Vas 0 262 cuM Qms 3 78 Qes 0 40 Qts 0 36 137 Chapter 7 Freq Phase 3 12 1 15 FA Reve The simulation curve shows a close match to the original data This result 1s fairly typical for most loudspeakers These parameters were generated for the LEAP model Speaker Parameters Processing Menu DEC Phase Imp 3 1 Freq MI 38 pkrhdadel 15 FA Reve 583 262 761 mi 0 364 37 323 Impedance vs Fre 0 700 A e e e C e r e r D C ir C ea tT ii e tT E oo zn r r r r e 99 600m N 20 LMS 4 1 User Manual n
216. llator A similar type of measurement can be performed with LMS The goal of the rub and buzz measurement 15 to detect upper frequency harmonics or noise caused by the mis aligned voice coil or particle lodged in the gap area The level of this noise can be quite low and likely below the ambient noise environment of the typical production facility For this reason the physical setup for doing Rub and Buzz measurements is fairly critical In order to measure such low level noise the driver and microphone must be acoustically isolated from the usual ambient noise level found in a manufacturing plant This typically takes the form of a small isolation chamber 4 x4 x4 lined with acoustic damping material The microphone is located inside the box at one end The opposite wall has a hole the diameter of the driver cone From the outside of the box the speaker is placed face down as shown below DEVICE TO TEST 325 Misc Applications Chapter 16 The setup for the LMS analyzer parameters would be as follows Meter Filter 1 and Meter Filter 2 Filter Type Highpass Osc Freq Tracking ON FreqRatio 7 000 F O Sweep Control Meter Input Microphone Data Type SPL Normal Data Mode Precision No of Data Points 30 50 The frequency range required will depend on the type of transducer being tested Generally the range where the majority of buzz sound occurs is from the resonance frequency of the transducer to about 10 times that f
217. lyzer Control Panel You are now probably anxious to start using your LMS as soon as possible If you wish to get started immediately this chapter will provide the necessary information to start using the LMS in the shortest amount of time This chapter will take you through a fast introduction to making basic SPL and Impedance measurements The first item in the Analyzer Menu is Parameters This could also be called the analyzer control panel since it provides direct control over virtually all aspects of the analyzer hardware Sweep Ose On Off F1 Another means to activate this window is by using the first tool pU ME button in the Analyzer toolbar shown as a seven segment Macro Fun character If you prefer to use the keyboard the shortcut key CTRL A will perform the same task Microphone Setup Calibration The Analyzer Parameters dialog is shown below This is a modeless dialog meaning that it does not prevent other dialogs from being displayed simultaneously This dialog also has a RollUp RollDown button shown in the upper right hand corner of the title bar Because this dialog 1s often left open on top of the graph the RollUp function reduces the size to merely the title bar thus enabling greater visibility of the graph underneath There are also shortcut keys for RollUp RollDown using CTRL PgUp and CTRL PgDn Also the F2 key can be used to toggle RollUp RollDown as well Analyze
218. lyzer Menu 84 Chapter 6 Note Iffull range measurements are to be made down to low frequencies such as 20Hz ground plane anechoic half space measurements or near field techniques are required These are discussed in the SPL Applications chapter Meter Panel The two list boxes select the type of data and the source for the measurement The Source list box contains the following selections Osc Internal Line Output Line Input Mic Input Note 7he OSC INTERNAL selection monitors the direct oscillator level it is not effected by the condition of the OSC On Off setting This source is always ON It does follow the OSC Level By selecting the Line Input external levels can be measured from other sources For example this input line could be connected to the output of a power amp to measure the output level from the amp 20dBm maximum Selecting the Mic Input will measure the level at the LMS microphone input Note If the SPL data type is selected along with the Line Input or Mic Input the MDF setup data will be used to produce the actual SPL measurements The Data list box contains eight different selections as described here Volts The oscillator produces a continuous or gated sinewave tone for each fre quency point and the meter measures the level at the selected source The oscillator then steps to the next frequency and the process is repeated SPL Same as Volts but with the additional computation of SPL as defined by
219. ment microphone At times it can be desireable to modify or load a different MDF mic file These curves can be loaded transferred to a library curve entry and otherwise manipulated using the Utilities MDF Editor Youcan then view this curve in the normal fashion on the graph A typical example is shown in the figure below With the curve now in a library entry you can now perform any of the utility operations on it or with it to generate new curves Let us assume that we have an anechoic chamber that needs to have the low frequency range corrected Most chambers will have a raising response at low frequencies below a certain threshold If we know what the room EQ curve should look like we can create it manually as outlined in the previous section An example of an EQ curve is shown in the top graph on the next page We wish to multiply this EQ curve into the original mic response curve After they are multiplied together the result is shown on the bottom graph of the next page This curve can then be transferred into the MDF Editor to produce a new MDF file which contains the additional room EQ Ratio vs Freq 80 T 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 337 Chapter 16 Misc Applications Ratio vs Fre 20K 10K 5K 2K 1K 500 200 100 50 20
220. meters above to anything you desire These two parameters together define the sensitivity of the mic along with the values in the normalized response curve Index Frequency Magnitude Phase This tabular listing gives the normalized frequency response of the mic You can edit these values directly or copy paste them from a spreadsheet program Although the curve includes a phase column LMS does not use this data The standard normalizing frequency is IKHz for MDF response curves but any other frequency can actually be used LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu File Transfer Clicking the Load MDF File button will open a dialog to load the data from an existing MDF file Clicking the Save MDF File button will write an MDF file using the data within this dialog MDF files should always have an MDF extension Setup Transfer When MDF files are installed into the Mic or Line inputs using the Analyzer MDF Setup operation the data is saved internally within the LMS INI file and used by the program on a continual basis to calibrate the SPL measurements These two buttons can be used to retrieve the MDF data from either of the associated inputs Curve Library The normalized response curve can be saved to or loaded from a library curve entry This is probably the most common means of working with the response curve It does not affect any of the text or numeric field parameters The curve list box prov
221. ml set la Spl set la zImpzWwire set la Mac3 set la Spl_gate set la Imp wire set la Polri k set la Test set la set la Wirub set la Rub z set os Files of type Set Files Cancel LMS 4 1 53 User Manual File Menu 54 Chapter 4 4 8 Save QuickSet File File zi Bos amp iuE SmBIiIBsS3zs e Hew Ctri M Open Ctrl Reopen k Etits Gaves Revert The File Save QuickSet File menu item saves a QuickSet file The tool button as shown above can also Load QuickSet File be used to activate this item Save QuickSet File Em QuickSet files store confi guration parameters from the Analyzer Parameters dialog Preferences E zit Ctrl File Save QuickSet File presents a dialog to specify the QuickSet file name and folder to save You may choose to save QuickSet files on a project basis or place the files in the common Set folder QuickSet files have an extension of SET You should always use the default extension Itis notrecommended that you use other extensions or you may not recognize the files in the future Save QuickSet File Save ir Set EN zimp set la zImpzWwire set la Maca set gate set Imp wire set la Polri k set Test set la set la Wwb set la Rub set la z set File name 5 Save as type Set Files Cancel LMS 4 1
222. mmand Reference Macro Command Listing Macro Run Dialog LMS 4 1 User Manual Contents Chapter 14 SPL Applications 14 1 Measuring Methods for SPL 14 2 Anechoic Chamber Measurements 14 3 Ground Plane Measurements 14 4 Half Space Pit Measurements 14 5 Near Field Measurements 14 6 Gated SPL Measurements 14 7 SPL Response of Car Interior 14 8 Acoustical Summations Chapter 15 Impedance Applications 15 1 Measuring Methods for Impedance 15 2 Impedance by Constant Current 15 3 Impedance by Constant Voltage 15 4 Using LMS for Speaker Parameters Chapter 16 Misc Applications LMS 4 1 User Manual 16 1 Passive Network Transfer Functions 16 2 Acoustical Rub and Buzz Testing 16 3 Electrical Rub and Buzz Testing 16 4 Creating Curve Data Manually 16 5 Modifing the Mic Calibration Curve 16 6
223. mo ZMVICO gt lt PLAN Zout 1002 x 2 1V 1A 2 5A max 1 1 LMS 4 1 User Manual Chapter 15 LMS 4 1 User Manual Impedance Applications Since a voltage sweep will be taken and then used when divided by the current sweep the frequency response of the amplifier will be cancelled out This dramati cally reduces the demand of a perfectly flat response for the amplifier This is very helpful In this example a 3 way enclosure will be measured The impedance will be determined at three different power levels 0 1W and 10W Based on a nominal Z of 8 Ohms The voltage drive levels will be 0 9V 2 83V and 9Volts respectively A current sweep will be taken at each drive level The figure below shows the voltage curves The maximum input level for the LMS balanced line input is 8 Vrms on either of the signal pins 2 3 Be careful not to exceed this input level power amps can far exceed this voltage If you are going to do a lot of measurements at the output of a power amp use the 40dB setting for output voltage on the VI Box The voltage curves will not be a perfectly flat line This is due to a voltage divider effect caused by the shunt cable resistance and the speaker load impedance The speaker s impedance 15 not flat but changes with frequency Impedance vs Fre Deg 500m 200m 311 Impedance Applications 312 Chapter 15 Since we are measuring the vol
224. mpedance value at the static test frequency shown in the Value field of the Meter panel You can move the frequency around and watch the Impedance readout change We can now run a sweep by pressing F9 or using the tool button and or menu item selection under Analyzer When the sweep is completed click the Graph button in the Sweep group panel 2 LMS Test lib You will probably need to adjust the scales for your data so choose the Scale Auto menu item as well Scale Auto 42 LMS 4 1 User Manual Chapter 3 Getting Started The graph should now show an impedance curve similar to what is shown below Again your data will of course be different For additional information on the operation of the LMS analyzer for measurements and software features read the other chapters and application information File Graph Analyzer Processing Utilities Scale View ToolBars Help Analyzer Parameters Oscillato Mod Output Level 6 000 m V HiSpeed Data v me Frequency 448 813 H Hz Precision Data Gatin Of C On Mete Data Impedance Value Ohm Source Line Output Freq 0000 Hz Graph Lo Freg Hz HiFreq Hz Points 10 000 40 000K 400 Control Osc On Off F10 TTL Pulse Gate Time Calculator 74 Meter Filter 1 Filter Function Fiat gt ck Ratio 1 000 Frequency 448 813 Meter Filter Filter Fun
225. must be generated for each of the two curves Run the Processing Minimum Phase routine on both of the curves LMS 4 1 User Manual Chapter 15 LMS 4 1 User Manual Impedance Applications View the Impedance Curves The impedance curves should be checked on the LMS graph display to insure that they are correct Thisisshowninthe graph below It will be noted that the resonance of the delta mass curve is now lower than the free air curve This is of course due to the added mass Impedance vs Freq Ohm Running the Speaker Parameters The curves now can be used with the Processing Speaker Parameters dialog The additional parameters of Revc Sd and Md must be entered and the appropriate library curves selected which contain the sweep curves After the derivation process is complete the dialog appears as shown on the following page If you prefer different units for various parameters these can be easily change by simply clicking the small arrow button above the edit fields You will be stepped through a list of possible units The parameter derivation process also produces a simulation of the speaker s impedance curves based on the model parameters This 1s shown in the graph on the following page as the Red curves The simulation curves look very similar to the original measured impedance data 317 Impedance Applications 318 Chapte
226. n Vector is selected the only active control is the vector format list box 167 Utilities Menu Chapter 8 Export Graphics EI Resolution DPI Artwork Use the two stepper buttons to increase or decrease this Graph SPL vs Freq value The value will be changed in units of 8 Forma Fr Vector net Color Format C Raster BMP windows BitMapFomat x The possible color choices are B amp W 16 Color 256 Color pe 120 A Uncompressed 1 16M Color 16 Gray 256 Gray Depending on the file Image Widthe 1200 Image Bits per Pixels _24 format not all color choices may be available Image Five Hegh Er Image Bptes TESTOR File Fat Compression C Program Files LMS E xport testnew PDF Browse Some of the raster file formats have optional compression If so you will be able to choose either compressed or __ uncompressed For other file formats this selection will be chosen for you File Path This panel displays the file name to be exported along with the Browse button The Browse button allows you to select the file name to be exported which can also be done by entering the name manually in the edit field The default file extension is controlled by the type of file format that will be exported It is not recommended that you change it Raster Images Raster images are bitmap representations of the artwork They are formed by rows of pixels They can be colororblack
227. ndix LMS 4 1 User Manual Appendix 352 LMS 4 1 User Manual LMS 4 1 User Manual Appendix Appendix A SI Units Floating point numbers can be entered in any of three forms real number format scientific format or engineering format Examples of each are 2400 75 real 2 40075E3 or 2 40075D3 scientific 2 40075K engineering A floating point number must not contain spaces Therefore do not place spaces between suffixes and other digits Note that the scientific format supports the use of either the E or D character to separate the exponent Lower case is also supported The engineering format is used entirely throughout the program for numeric display These are single character multiplier suffixes which appear at the end of a floating point value Note that in virtually all of the suffix chars the following convention is used upper case is used for multipliers greater than unity and lower case 15 used for multipliers smaller than unity The only exception is the kilo suffix where both cases are supported K or k The entire list of SI multipliers is shown below Use of the exa suffix E can lead to Sl Multipliers confusion since the standard scien Name Value Suffix Name Value Suffix tific notation uses the letter E as well e g 1 234E 5 The program kilo 10 K k milli 10 m assumes that 1f the E character 1s the last character 1n the number it is treated as the exa multiplier
228. nel A scale tab is defined for every possible type of vertical data used within the program The operation and use ofthe fields in these tabs are essentially identical for all of them For this reason only the Voltage tab will be described here as an example All others are similar Axis There are three choices for the type of axis Linear Log and dB If the Linear or Log selections are used the curves will be plotted 1n units of Volts If the dB selection is used the curves are plotted in dBV or dBm depending on the dB Reference chosen Polarity If you are using a Linear axis then you have a choice of either Bipolar Positive or Negative scale range A Bipolar scale means that zero is in the center of the scale and the range might be 1 0 to 1 0 volts A Positive scale means that zero is at the bottom and might contain a range such as 1 0 to 0 0 volts A Negative scale means that zero is at the top and might contain a range such as 0 0 to 1 0 volts Range The Max and Min values here define the range of the scale Depending on other parameters in the tab one of these parameters may be disabled If you are using a Log axis the Min value cannot be zero or negative dB When the dB axis is in use two parameters here are enabled dB per Division and dB Reference The number of dB per major division controls the resolution of the scale The dB reference defines the OdB value For volts it is either 1 000 dB V or 0 77
229. nge to a different curve group use the spin buttons in the status bar or the Up Dn arrow keys on the keyboard The cursor will only track curves which are selected for display The Absolute Relative buttons select the cursor measurement mode When you press Relative another black cursor will appear at the current position As you move the cursor the displayed data will be calculated relative to the reference position Pressing the Absolute button will return to normal mode 2 LMS Sample lib ef x Ele Graph Analyzer Processing Utilities Scale View ToolBars Help Beat Sas RRBBBBE PME ET f BB Bk T A 4 9 SPL vs Freq dBSPL Deg 100 180 AVR s 95 150 M N 10 120 85 90 ial 80 160 75 30 70 LL 0 YIN a 65 7 1 30 60 d 60 55 y f 90 50 WI 120 45 150 Fe 180 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K afl 141 abs Re 1 P25 at 1M Hi 23196 Hz 83974dBSPL Let _Right Cursor Controls and Readouts LMS 4 1 User Manual Chapter 2 LMS 4 1 User Manual General Features 2 3 Zoom Progress Meter and Messages There are several other segmented panels on the status bar On the left the current Zoom level of the graph is shown On the right two cells show the progress meter and a message zone for vario
230. nteger 1 through 50 This command will ask the operator to enter a name for the curve entry specified here Example 100 NAMECURVE 11 OKBEEP Beep Sound The OKBEEP keyword is used to produce a beep sound from the computer The user can use this command to signal the operator Example 100 OKBEEP ONFAILGOTO Line Number If Compare test fails jump to Line Num The ONFAILGOTO keyword is used sometime after a COMPARE or RELCOMPARE test to make a jump to a different line number if the test failed Example 100 ONFAILGOTO 250 PAUSE message Pause for key press The PAUSE keyword is used to cause the system to stop and wait for the operator to press a key any key The command line is also automatically cleared first and the message is displayed The message should be in double quotes The command line is again cleared after the key is pressed Example 100 PAUSE Connect Cables Hit any key when ready PHASE entrynumA Generate the Minimum Phase for CurveNum The PHASE keyword is used to produce the minimum phase curve for the magnitude response in curve A The parameter must be an integer and between through 50 Example 100 PHASE 11 B PRINT Print Graph The PRINT keyword is used to print a graph The printer setup that is currently active in the software will be used It is the users responsibility to see that the proper settings have been established prior to running the program or before executing t
231. nual Processing Menu Chapter 7 Delay Offset This operation modifies the phase function of a curve to increase or decrease the equivalent delay specified in the edit field It is the equivalent of shifting the phase response by a finite delay offset This operation is commonly used to move a response forward or backward in time However many other purposes can be found for unusual effects For example to move an SPL response backward by 1 Inch offset the response by 73uSec In the graphs below the Blue curve was shifted by 500uSec with the resulting curve shown in Red The Group Delay Transform was run on each curve and is shown inthe second graph The additional 500uS of delay 1s clearly visible Voltage vs f req 108 LMS 4 1 User Manual Chapter 7 Processing Menu Exponentiation This operation raises the curve to the exponent power specified by the numeric Pwr value This operation effects both magnitude and phase The operation is commonly used to square the response of a curve Pwr 2 0 or perhaps take the square root of a curve Pwr 0 5 By using an exponent power of 1 0 the curve can be inverted In the graph below the Yellow curve is the square root 0 5 result
232. ny curve which is currently being dis played on the graph is denoted by Red vertical lines between the zones of each curve entry Interpalatio Linear Freq SPL Phase Horz Hi Limit Quadratic Cubic 151 Processing Menu 152 Chapter 7 Since the curve s data will be altered you may wish to make a copy of the curve before performing this operation This will prevent loosing your original data curve should you wish to run the operation again on the original data An example of data realignment is shown below The first graph shows a 500 point log frequency SPL response from 10Hz 40kHz The second graph shows the result of realigning the data to 100 points from 20Hz 20kHz again with log resolution SPL vs Freq dBSPL 40 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K SPL vs Freq dBSPL Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Realign Curve Averaging Curve Compare
233. o as a command line parameter under windows a shortcut link must be created to the LMS EXE application program It will be assumed that you know how to create shortcuts within the Windows operating system If not please consult the Windows Help documentation There are many different ways to create shortcuts and they can be placed anywhere on your desktop or inside other folders One suggestion is to create a folder under your LMS directory tree called Macro Programs and then place all your autorun shortcuts in this folder First create a shortcut to the LMS EXE file Then edit the ees ib properties for the shortcut as shown here In the Target ass eei edit field the path to the LMS EXE file will be given LMS TEST MAC inside double quotes Target type Application Append a space and then enter the file path to the macro Target location LMS file you wish to run When done click Ok Target foaram Files LMS LMS EXE EALMS Mac Test Mac WU DEUM You can rename the shortcut link to whatever you like Generally a name denoting what macro will be run is a Start in C Program Files LMS good idea Shortcut Kev None Roma indon When you double click on the shortcut link icon the LMS software is started and the macro program is immediately Find Target Changelcon run The application program is under macro control until it is terminated or the macro ends 254 LMS 4 1 User Manual Chapter 13 LMS 4 1 U
234. o take near field measurements on the woofer and port and a gated measurement on the full enclosure to capture the mid and high frequency ranges These curves could then be spliced together to form a complete full range curve This method is more complex and more work but it does allow full range curves to be produced in any environment The drawing below shows the typical mic positions for measuring the woofer and port In far field measurements the SPL output from the woofer and port are summed together acoustically When taking near field measurements on the woofer the port output does not appear in the pressure at the woofer For this reason ported enclosures require separate measurements to be taken at the woofer cone and at the port These must then be summed together mathemati cally within the LMS software as a post processing operation The real goal here is to be able to measure the near field SPL and then to predict what the SPL would occur at a far field distance such as 1 Meter This can be done if the piston area for the source is known Itis simply a matter of scaling The following formula gives the ratio of far field presure to near field pressure at 1 Meter referenced to half space far field Scaling Factor for Near Field 1M half space Pfar Pnear 0 2821 sqrt Sd Sd in sqM MIC WOOFER This can be thought of as the scaling factor for near T 0 25In Dust Cap field measurements If you wish to know the scaling
235. o the LMS output XLR The alligator clips can then be connected easily to speakers for measuring impedance All of the input output lines of the LMS analyzer are standard 3 Pin XLR type You can add your own extension cables to any of these lines as needed to suit your requirements The microphone has an internal hybrid preamp line driver for handling long cables As much as 250Ft of mic cable can be added to the microphone input with minimal loss at high frequencies The figure below can be used if custom cables are to be constructed directly to the LMS PC Card The pin functions are self explanatory The return ground for the TTL Pulse output Pin 13 can be any of the common pins eg Pin 12 Note Be careful not to short the TTL pin to ground or a supply voltage line This is a direct output from an LSTTL bus driver IC This could damage the IC Note On LMS PCBs DB 15 Connector Female MIC with serial number less PREAMP 138203 the TTL MIC PIN1 gt output is not brought MIC PIN2 out to pin 13 on the COMMON gt DB15 If you wish to COMMON gt use the pulse output COMMON contact LinearX for detailed information LINE PIN 3 gt COMMON gt LINE PIN 2 TTL PULSE LINE PIN 1 o COMMON gt OSC PIN2 gt OSC PIN3 gt OSCPIN1 gt LMS Card DB15F Connector Pin Functions Installation 10 Chapter 1 1 5 Starting the Program Once the installation program has
236. ocess You will be returned to the program after this button is pressed Note When you exit the program all of the configuration data is stored in the LMS INI file and will be restored the next time you start the program Closing Library x Library has changed since last saved Save 5ample lib file Cancel LMS 4 1 User Manual Chapter 5 LMS 4 1 User Manual Graph Menu Graph Menu 5 Graph Parameters E Curve Library FE Mates amp Comments 65 Graph Menu Chapter 5 66 LMS 4 1 User Manual Chapter 5 Graph Parameters Graph Menu 5 1 Parameters The Graph Parameters menu item will TEE Parameters En open a dialog which controls the appearance mj wj Notes amp Comments of graph artwork within the program The tool button as shown above can also be used to activate this item This dialog allows you to define the colors lines and fonts commonly used on the graphs of the program By using these parameters a very wide range of different graph designs can be easily produced Graphics dimensions are always given in mils 1 1000 of an Inch For example a 10 mil line is 0 010 Inches Frame Parameters The Background color is applied across the entire area of the graph page The Note Underline controls the color and width of the lines under the user note text The Large Frame Line controls the color and line width of the border around the graph The Small Frame Lin
237. od Rd Tualatin OR 97062 8586 USA TEL 503 612 9565 FAX 503 612 9344 Internet www linearx com Copyright 2000 LinearX Systems Inc All rights reserved All other Trademarks are the property of their respective owners LMS 4 1 iii User Manual Contents Technical Support LinearX provides detailed printed manuals and on line help within the program as the primary source for user information and assistance regarding the use of this product If these sources do not contain the answers to your questions contact LinearX via any of the following methods Internet Email support linearx com Internet Web www linearx com Fax 503 612 9344 Tel 503 612 9565 Technical support is free and unlimited at this time however we reserve the right to charge for this service in the future as conditions overhead and support personnel requirements dictate When contacting us regarding a technical support issue PLEASE follow these steps to aid us in understanding and solving your problem 1 The About Box contains a procedure for generating a SYSCONFIG TXT file This file can be created by the user through the About Box and contains all of the information about your computer system and operating system If you feel that your question could involve issues relating to your computer operating system please produce this file and attach it along with your fax or Email question 2 If your question involves specific details or parameters unique
238. of how an enclosure will perform when used in a car environment When a loudspeaker system is designed based on measurements in a controlled open environment its response inside a small closed space can be expected to be quite different In the following test an enclosure was measured first in a ground plane setting and then measured again inside a car interior The two curves were then divided to produce a ratio The ratio curve is the dB difference between the ground plane environment and the car environment The actual response of the enclosure becomes virtually irrelevant Since it 1s of course present in both curves its own frequency response is canceled out SPL vs Freq sj m Response with Ground Plane and Car Interiors LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications There are three curves shown in the graph on the previous page The solid line is that of the enclosure measured under ground plane conditions The dotted curve is the enclosure measured inside the car with all windows closed The dashed curve is the enclosure in the car with the driver and passenger windows both down The ground plane response is quite smooth without reflections while both of the inside Car response curves show a tremendous amount of reflections Also both responses inside the car show a marked increase in level at the low end with respect to that of the ground plane measurement To better see the tendencies
239. of impedance changing with level is shown in the graphs onthe following page Herea 15 speakeris tested in a ported box at 4 power levels of 1 10W 1W 10W 100W Note how the impedance changes near the port tuning Port nonlinearity is shown at even the low level of 1 Watt You may be interested to know how the LMS constant current measurement compares to these constant voltage measurements A comparison of the 1 10W constant voltage Z curve and the LMS direct impedance sweep is shown on the next page Note that at mid and high frequencies the curves overlay exactly on top of each other Only a small difference 1s shown at the low end D a GO CE QC _ _ I LT B n u E E lt lt LEFT 1 5 a a HH Hz 20 50 100 10K 20K 40K Ex ES E ES al R Impedance Result Curves at 3 Power Levels LMS 4 1 313 User Manual Chapter 15 Impedance Applications Impedance vs Fre 5 ANH IUD EIE ERI RC 12017 4 EON ARDT 10 Hz Impedance of Constant Voltage vs Current Impedance vs Fre z e a N eco EN EN EEE EN RE DLL ml OL DR OR LU LU EU CRU
240. of the Syntax Checker that is built in This will catch many of your obvious errors When you receive an error message note what the message says In most cases this will inform you about the problem Also the line number of where the error occurred will point you straight at the line that needs to be fixed Check the syntax for the command to make sure you are using the command correctly and that it has been entered correctly Because of memory limitations the LMS interpreter will certainly not catch all possible errors and in some cases provide very limited information about the cause of the problem However the language is quite simple and far less complex than conventional programming languages The smaller set of commands will generally make the problem easier to locate Note If you need to terminate the execution of a program while it is running press ESC or CTRL END This will return you to the LMS software You will need to press ESC twice if a sweep is in progress 257 Macro Programs 258 Chapter 13 13 6 Planning A Macro Program Before writing the actual program it is generally a good idea to plan what tests are to be run and what operations the program will need to use This sort of flowchart makes writing the program much easier Also study the sample programs provided They will help you to see how a typical program is constructed In most cases you will need to prepare various curves libraries or Qui
241. of the original Blue curve the Red curve is the squared 2 0 result and the Green curve is the inverted 1 0 result Voltage vs Freq dBm LMS 4 1 109 User Manual Processing Menu Chapter 7 Smooth Curve This operation performs an averaging of the data to smooth the response by the bandwidth specified in octaves Each frequency data point becomes the average of a group of points above and below each spanning the specified octave width of that curve s frequency range This operation effects both magnitude and phase The operation is generally used when you wish to remove excess noise or detail from a response curve In the graph below the Black curve was smoothed by a value of 0 5 Octaves as shown in the Red curve 2 SPL vs 30 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 110 LMS 4 1 User Manual Chapter 7 Processing Menu Frequency Translation The frequency translation operation shifts the frequency locations of the curve data by a numeric Ratio value This operation effects both magnitude and phase The operation is rarely used but sometimes is necessary when producing digital filters and can also be used to correct imported measured data Many other appli
242. om messages on the screen waiting for the operator to press akey performing looping and providing conditional goto statements Macro Changes in LMS Version 4 Win32 With the introduction of LMS version 4 0 for Win32 many of the macro commands and their behavior have now changed For customers who have previously constructed macros for operation under LMS 3 for DOS some changes or modifications to your programs will probably be required Some of the commands simply have no relevance in the Windows environment at all In other cases the operating system itself handles things very differently and the application program has no control over particular aspects of system operation The Macro Command Reference which follows in a later section will describe how some of these commands have now changed in version 4 for Windows 253 Macro Programs Chapter 13 13 2 Running Macro Programs There are three different ways a macro program can be run Use the Analyzer Macro Run menu item or tool button Run the macro from within the Utilities Macro Editor AutoRun the macro as a command line parameter when starting LMS The first two methods have already been covered in their appropriate chapters and sections The last method we will describe here When a macro is run as acommand line parameter the macro is started when the software is launched eer op Creating a Window s ShortCut to AutoRun a Macro File Edit View Help To run a macr
243. on the status bar at the bottom The graph area displays a grid using the current system frequency for the horizontal axis and a vertical axis dependent on scale settings and type of data Two rulers are displayed in Black on the left and top sides of the graph The right and bottom sides contain scroll bars when necessary The graph displays the edit curve as straight line segments drawn between nodes which appear as dots When a node is unselected it is colored Gray When a node is selected it becomes Red More than one node can be selected simultaneously Library Curves can also be shown on the graph along with guidelines pulled from the rulers 182 LMS 4 1 User Manual Chapter 8 Control Graph Mo Mew Save ChS Revert Cancel Ok LMS 4 1 User Manual Utilities Menu Control Menu This menu contains operations similar to those listed on most File type menus However since the Curve Editor is part of the overall program and does not handle files directly this menu is named Control New This menu item will create initialize a new set of the two graph edit curves using the current system frequency range Both two edit curves will be given 10 nodes each with flat line values at the center of the grids This operation is generally used when first starting an editing project to move the nodes into the system frequency range Save This menu item will save all the current settings and parameters of the C
244. onds per frequency data point It should also be noted that due to the random decay characteristics and standing waves in many rooms every RT60 sweep will have slightly different curve results Decay characteristics tend to be very nonlinear The two black fields display the active measurements for the Value and Freq of the analyzer source You can change the color of the readouts by clicking on the fields You will be toggled through a list of preset colors The type of value units will depend on the type of data Unit buttons are provided for both readout fields to change the form of the displayed data Note Static measurements are performed automatically and continuously whenever this dialog is visible Sweep Panel The controls in this panel determine where the sweep data will be placed in the curve library over what frequency range and with what resolution The Lo Hi Freq edit boxes determine the limits of the sweep The Points edit box defines the number of log spaced points to be measured between these two frequency limits The Up Down option determines whetherthe sweep progresses up or down in frequency The Data Curve list box provides selection of the library curve where the next sweep data will be placed This special list box shows the type of data contained in each curve After a sweep is completed this will be updated Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zone
245. onse curve The graph at the bottom shows the FFT transformed response in the frequency domain If you compare this to the other frequency domain curve in the previous Inv FFT section you will note that much of the low frequency resolution has been lost This is due to the linear frequency resolution and 4096 sample size Voltage vs Time Voltage vs Freq 120 50 150 55 180 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 129 Processing Menu Chapter 7 130 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Curve Averaging Curve Compare Speaker Parameters Metho Es Curve Elec Motor Sinale Curve with Mmd Double Curve Delta Mass Double Curve Delta Comp Model Parameters Data Transfer Mode Standard LEAP Reve Ohm Mmd 5 720 1 000 Fa Hz Km Ohm Kxm Ohm Cms Levc Mms TM Processing Menu 7 8 Speaker Parameters P E E ES AMM DAB The Processing Speaker Parameters menu item will open
246. ontents F1 Index Glossary About Modules About Program LMS 4 1 239 User Manual Help Menu Chapter 12 240 LMS 4 1 User Manual Chapter 12 Help Menu 12 1 Contents The Help Contents menu item will open the help Re system and display the contents panel This item can des also be activated by using the F7 shortcut key Glossary The contents panel provides a table of contents for the help file This function is most commonly used when you wish to browse the help file by different subjects About Modules About Program Help Topics Help HE Contents Index Find Click a topic and then click Display Or click another tab such as Index e Reference Manual C Application M anual Print Cancel LMS 4 1 241 User Manual Help Menu Chapter 12 242 LMS 4 1 User Manual Chapter 12 12 2 Index Help Contents F1 Glossary About Modules Help Menu The Help Index menu item will open the help system and display the Index panel The index panel provides a listing of the topics which have been indexed in the help file This function is most commonly used when you wish to search for key About Program purpose Help Topics Help HE Contents Index Find 1 Type the first few letters of the word vou re looking for Buffer Component 2 Click the index entry pau want and then click Display Approsimation Approximation vs Optimization Elli
247. operand curves can be anything but the result curve is always created using the operand A curve frequency range The program performs automatic frequency translation for the operand curves The dialog use is straightforward Simply select the math op the two operand curves and the location for the result curve The Mul and Div operations attempt to keep track of the units when possible For example when dividing two curves with identical units the result curve will be given the Ratio type If you are multiplying impedance and current the result curve will be voltage If you are dividing voltage by current the result curve will be impedance etc x If you wish to change the type of units on the curve either operand or result curves you can do so in the curve library dialog See the chapter Graph Curve Sub Resulta4 B Library SPL Phase SPL Phase Freq Cancel Help 115 Processing Menu Chapter 7 An example of using the Div operation is shown below This operation is frequently used to obtain the ratio between two curves Inthis case we havetwo voltage curves Dividing the Bandpass filter Blue by the Highpass Lowpass Black curve produces the ratio curve shown in the lower graph The result curve is always enabled for display after the operation is performed However often it will have different units then the operand curves and cannot be shown on the graph simultane
248. or Div values control the design of the horizontal grid There are two different plotting choices rectangular or circular The circular plotis most commonly used for polar plots but rectangular plots are also used A data grid 1s displayed along with three buttons Make Clear Sort Once you have defined the Min Max time values clicking Make will generate a suitable list of labels for the scale The generated labels are then listed in the data grid The generated labels are placed at the major divisions of the horizontal grid lines If you wish to delete the entire label list click the Clear button Single labels can be deleted simply by erasing the text in the desired entry Additional labels can be added using the empty locations further down the list Clicking the Sort button will sort the list based on the time value represented in the label text Note The labeling controls will be disabled if the Automatic Labels option is enabled in File Preferences LMS 4 1 User Manual Chapter 9 LMS 4 1 User Manual Scale Menu Inductance Capacitance Excursion Velocity Acceleration Time Phase SPL Voltage Current Impedance Ratio Hang Max 10 0000 Min 110 000 E dB i Bipolar Per Div 10 000 Prefix 7 Positive zem Ret Em dem Negative el ear Fort Vertical Scales There are twelve different unit tabs on the vertical scale pa
249. or each data point This would normally be used to control a stepper motor turntable The frequency is that set by the OSCILLATOR section s FREQUENCY parameter The number of data points selected should equal 360 degrees divided by the degrees per pulse of the turntable Polar SPL Same as Polar Volts but with the additional computation of SPL as defined by the assigned MDF data for either the Mic or Line inputs RT60 The RT60 data type is used to produce a decay curve showing the time required for a given level to decay 60dB at a given frequency This is commonly used for measuring the characteristics of aroom or auditorium This sweep turns on the OSC for five seconds to saturate the room with sound and allow the standing waves to build and then turns it off and takes a series of measurements as the level falls Due to noise in the environment analyzers rarely measure the actual time for the level to drop a full 60dB Rather they measure the time required for the level to drop a finite amount and then extrapolate to determine the time required to reach 60dB With LMS the dB differential can be selected by the user in the File Parameters dialog Depending on the level of noise in your environment you may need to adjust this lower or may be able to set this higher as desired 85 Analyzer Menu 86 Chapter 6 Typically 10 30 data points are taken for reverb time measurements This measurement does require a total of about 10 sec
250. or output XLR you will not need an amplifier You will LMS 4 1 User Manual need to make an adapter cable consisting of a female XLR with a fan out to two individual wires with alligator clips Bring out pins 2 and 3 from the XLR to the clips as shown in the figure here It does not matter which of the two wires are connected to the positive terminal of the speaker Polarity is irrelevant in this measurement Note The direct impedance measurement method provided by LMS is only suitable for loudspeaker impedance measurements where the load impedance is typically in the range of 4 400 Ohms If your load is outside this range then a different method such as employed by our VI Box should be used There are two methods of measuring direct impedance using LMS 2 Wire and 4 Wire In the 2 Wire mode only the Osc output is connected to the load and the Line Output is then selected as the Source in the Meter panel In the 4 Wire mode the Line Inputs also used and directly connected at the load terminals In this way the line cable resistance is removed from the measurement For this example the simple 2 Wire method will be used There are two different QuickSet files provided in the LMS Set folder Z mp2 Wire and Zlmp4Wire We will now load the Zlmp2Wire Set QuickSet file 41 Getting Started Chapter 3 Select the File Load QuickSet menu item and Lookin E Set 1 exl then choose the Z lmp2Wire set file Open the 3
251. ouble clicking over a scale region will open the Scale Parameters dialog The various regions are shown below There is also a popup menu available using the right mouse button which provides a listing of similar various common dialogs Graph Parameters Cursor Control SPL vs Freq T mW 180 50 100 200 500 1K 2K 5K 10K 40K se m C13 at 1M D25 at 1M P ATI Parking Lot 11 15 52 83v at Am Og Temp 25Ft 1503 Pair 4 0 0 224 Person Project Jun 13 2000 CINEARX Graph Parameters Note Parameters 20 LMS 4 1 User Manual Chapter 2 General Features 2 5 Quick View Window There are many occasions where you may wish a tighter view of a particular area of a graph A special window is provided with data displayed based on a dragged rubberband rectangle Rather than having to constantly change the scale factor for the graph you can drag arectangle using the mouse over the range of interest The Quick View window will appear with a smaller scale factor and frequency range There are two options for determining the vertical scale as controlled in the File Preferences dialog The frequency time limits will be rounded to the nearest major division and the number of vert horz divisions is the same as the main graph To close the Quick View press ESC or right click the mouse button
252. oughout the sweep Leveling a Normal Sweep to Remove Reflection Spikes Upon inspection of the normal sweep curve it can be said that the average of the curve 1s very similar to that of the gated sweep In fact if the curve is leveled or smoothed the response is very close to that of the true gated sweep This is shown in the graph below This curve was leveled with a 0 333 Octave factor This 15 virtually the same idea as the warble tone oscillator The effect of reflections can be largely evened out by leveling For best results though a high resolution sweep should be taken to produce a true average If only a small number of data points are used the full cancellation effect of the reflections and leveling may not be realized Comparison of Gated and Leveled Sweeps 291 SPL Applications 292 Chapter 14 14 7 Response of Car Interiors In some cases it may be desirable or necessary to include the effects of the environment This is most certainly true of car stereo systems This might also be of interest when the effects of a room are to be included in the measurement of SPL response Including the effects of the environmentis easy All that is required is to simply measure the enclosure in that environment The following discussion will even go beyond this and show the differences between a car interior and a ground plane measurement Using some ofthe utility features in LMS wecan gain an excellent understand ing
253. ously with the operand curves Voltage vs Freq dBm 90 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K Ratio vs Freq 116 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Tran form Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Curve Averaging Curve Compare LMS 4 1 User Manual Processing Menu 7 3 Minimum Phase Transform P E ES ES E3 Reb lud DAE AE amp amp The Processing Minimum Phase Transform menu item will open a dialog which provides a method of generating phase response data from magnitude only data The tool button as shown above on the Processing toolbar can also be used to activate this item The minimum phase transform is very valuable when you do not already have a phase function for your magnitude data This situation occurs with all LMS measured data since the analyzer itself 1s single channel and does not measure phase directly In other cases magnitude only data may be imported into the program then this routine can be used to construct a phase curve to provide f
254. ow Analyzer Calibration Ea Turpe Ce External Parameter Under Tes FregScale 0 18 000 Index Internal Calibratian Working If any of the tests fail there is probably a conflict dd with another board in the system causing data LMS I O port Oof1F Trnsfr Fatio 251 937 uV Hz PASSED corruption Attenuator Scale 259 968 mdB Step PASSED AutoBange Gain 1 3 986 Vs PASSED AutoRange Gain 2 10 116 V V PASSED If no LMS board is present then the routine will Gate Gain Ratio 0 957 Ratio PASSED Gate Freq Ratio 1 003 Ratio PASSED not run at all In this case either the computer 2 ae needs to be rebooted or there is some other VCO Freq fiset 592 Index PASSED 2 Freg cale z Zl 5z6 Index PASSED 1 1 gt 1 130 160 Index PASSED problem disabling the driver Freg cale z 10 449 Index PASSED Freq ffzet 2 342 Index PASSED 12 LMS 4 1 User Manual Chapter 1 LMS 4 1 User Manual Installation Next select the External option and press the Run button again The first test requests you to measure the Line Output voltage with an AC volts meter If you do not have one just keep the default value The system prompts you to connect the Line Output to a meter to measure the AC voltage between pins 2 and 3 If you do not have a meter simply leave the Output line unconnected and hit Enter or click the Ok button Nex
255. ow s NOTEPAD EXE basic editing program You can choose your own favorite editor by using the Browse button and selecting your editor s EXE file General Analyzer Editor Pat CAWINDOWS Matepad exe Browse Control Bar Textur MARBLE BMP Genera Show Splash Screen Auto Backup Library Files QuickView Scale From Data Auto Roll Up Analyzer Params Flash Sec Relative Cursor Mode Horz Dat f Absolute Frequency Time Curve Automatic Curve Notes Beep at end of Sweep Relative Frequency Time Optional Library File D at Graph Parameters Toolbar Parameters Font Parameters Mew Library Auto Color Scale ve Automatic Labels Auto Up Din Phase Analyzer Parameters 60 LMS 4 1 User Manual Chapter 4 LMS 4 1 User Manual File Menu General There are several check boxes which enable disable general options in the program The Show Splash Screen controls whether the initial introduction screen appears when you start the program The Auto Backup Library Files will automatically create a BAK version of your library file each time you save it The Quick View Scale from Data controls how the vertical auto scale is generated for the Quick View graph When disabled the vertical scale is produced by the major division values of the original graph When enabled the scale is adjusted to fit the data within the bounds of the selection rectangle The
256. ow to the crosshair as shown below You can then Click the left mouse button to select the node m Nodes can be deselected by clicking on a different node an empty area of the graph by rectangular selection of different nodes or by using the ESC key them as shown here on the left To append more nodes to other currently selected nodes hold down the CTRL key while selecting more nodes by either the single click or rectangle methods Selected nodes can also be removed from a group by the same method Multiple nodes can be selected by drawing a rectangle around Once the nodes are selected click and hold the left mouse button over one of the selected nodes and move All selected nodes will be moved by the same change in cursor position When a move operation is started the cursor 15 automatically aligned to the centered of the primary node being dragged by the mouse Selected nodes can also be deleted using the DELETE key Using the INSERT key will add nodes between any two existing selected or unselected nodes at the cursor position LMS 4 1 189 User Manual Utilities Menu Chapter 8 Reading Library Curves Reading an existing Library Curve is one means of obtaining reasonable starting values for a set of editing nodes However the user must decide how much starting density resolution is desired and set the Points parameter as needed prior to clicking the Read button The three samples below show a Library Curve
257. pper frequency range of the system 81 Analyzer Menu lt Oscillator On Time Chapter 6 Tracking Meter Filters have two frequency modes The filter can be either set at some discrete fixed frequency or set to track the oscillator s changing frequency during sweep When a filter is set to track mode the frequency of the filter is swept from high to low frequencies at a Ratio of the osc frequency When tracking is turned on the Ratio parameter is active When tracking is turned off the discrete single Frequency parameter is active Gate Timing Panel The four parameters on this panel all relate to setting the Gate operation when a gated measurement type is in use such as when making quasi anechoic SPL measurements in the SPL Gated data type These are Osc Off duration time Toff Osc On duration time Tosc Meter Delay time Tdly Meter On duration time Tmtr Setting these four controls is a straightforward and simple process Each control has a specific set of requirements and or rules that will be given shortly The oscillator is first programmed to produce a burst of sinewaves Odi for a period Tosc The meter input is initially turned off but after a preset amount of delay time Tdly expires is turned on The meter Meter Gate 82 Meter Delay Time Meter On Time SO input stays open for another period of time Tmtr while it captures the incoming signal and measures its le
258. ptic Filters Inverse ITA Transform 5 Root Editor AP1 1st Order Allpass Filter AP 2nd Order Allpass Filter Appendix amp 51 Units Appendix B References Appendix C Technical Support Authorization Installation BEH Bandpass Equalization Filter BP1 1st Order Bandpass Filter BH1 1st Order Bandreyect Filter Buffer Component Capacitor Component Circuit Calculate Cancel LMS 4 1 User Manual words The Find panel can also be used for this Help Menu Chapter 12 244 LMS 4 1 User Manual Chapter 12 LMS 4 1 User Manual 12 3 Glossary Contents F1 Index About Modules About Program Help File Edit Bookmark Options Help Contents Index Back Print Glc ssary Help Menu The Help Glossary menu item will open the help system and display the glossary selection buttons The glossary is an alphabetical listing of definitions for many of the terms used throughout the program Clicking on a letter button will open a popup window with a list of words beginning with that letter Select one of the words and another popup window will be displayed with the definition The Glossary can also be accessed by clicking the Glossary button in the toolbar lel Es 245 Help Menu Chapter 12 246 LMS 4 1 User Manual Chapter 12 Help Menu 12 4 About Modules The Help About Modules menu item will display a Canton F1 dialog which list
259. q Phase Delta M C Curve 2 15 45GRAMS Reve 3 12 mp Phase Free Air Reve Ohm Sd eg Vab cuM Md Inf Baffle 3 120 25 600m E 1 000 45 000 Standard LEAP Kg Levc Gms EL TM Ohm Ksm Ohm Cms 9747 4 555m 10725 251 7370 0 402 3 400 sgh 10 725m 70 622 3 775 11 401 Ho ESI Exm Vas cul SPLo dB 0 701 0 689 261 929m 0 363 97 318 Operatio Estimate Optimize Simulate Estimate Optimize Simulate 70 60 50 40 30 20 a Model Simulation Reference Curve 38 SpkiModel 15 Revc 31 Freq mp Phase Delta Curve 39 DeltaModel 15 FA Revc 3 Freq mp Phase Impedance vs Freq Deg 180 150 120 90 60 30 30 60 90 120 3 10 Hz 20 50 100 150 1 15 200 500 1K 2K 5K 10K 20K 40 180 K LMS 4 1 User Manual Chapter 7 LMS 4 1 User Manual Processing Menu Double Curve Delta Compliance This method is based on the use of two curves one reference curve and another delta curve where the speaker is mounted in a cabinet of known volume Complete electrical and mechanical parameters are derived for the loudspeaker based on the change
260. r 15 After the parameters are found they can be transferred to a disk file copied to the clipboard or printed It should be mentioned that the parameters are also copied automatically to the nfo text lines of the simulation curve entries Printing a graph with these curves will automatically contain the speaker parameters in the Notes amp Comments area of the graph Speaker Parameters Metho Single Curve Elec Motor Input Parameter Reference Curve 1 15 FA Reve 3 12 Freq Single Curve Elec System Single Curve with Mmd Double Curve Delta Mass Double Curve Delta Comp Delta M C Curve 2 45GRAMS Aevce 3 12 Freq mp f Feer Fevc Ohm Sd sgh Yab cuM Mud Inf Baffle 3 120 85 600m 1 000 j 45 000 Model Parameters Data Transfer Mode Standard LEAP4 Reve hm Mmd Kg Levc Mme Gms 3 120 66 221 mi 10 726m 70 622 3 77h 401 Fo Hz Erm Ohm Exm Ohm l E ard 4 555m 10 7 26m 251 7374 7 402 E 3 400 E m Vas SPLo dB Bm 01 0 699 261 929m 363 37 318 Model Simulation Reference Curve 38 SpkModel 15 FA Revc 3 1 Freq Imp Phase Operatio Estimate Optimize Simulate Estimate Optimize Simulate Delta M C Curve E DeltaModel 15 FA Revc 3 1Freq Imp Phase
261. r 3 Getting Started Looking at the graph again note that the Map legend now shows the name of the curve next to the line sample This is how you can easily identify the curves on the graph with their actual names in library We should now save our library Select the File Save menu item and enter a name such as Test Note that along the status baris a spin button This button can beused to select which curve the cursor tracks You can also use the keyboard arrow Up Dn keys as well When the cursor displays the curve name you can then move along the curve using the Left Right arrow keys or double click at another point on the curve and the cursor will jump to that point The Left Right data buttons control which side of the vertical data will be tracked left magnitude or right phase 2 LMS Test lib File Graph Analyzer Processing Utilities Scale View ToolBars Help 40 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 1 My New Curve EEE gt 4 132 abs 1 My New Curve j 17700 Hz 83180dBSPL Left _Right LMS 4 1 39 User Manual Getting Started EMI ERES File Graph EEIE Processing Utilities 5 E c CN m E Sweep Start Stop Ose On Off F10 RLC Meter Microphone Setup PAL Interface Macro Hun Calibration Analyzer Parameters Chapter 3 Let
262. r Parameters ail analyzer produces continuous Oscillato Mod readings while this dialog is visible Output Levl 35858 b ado The readings are shown in the black Frequency 100289 j He ue fields of the Meter group panel Gatin w Of C On Meter Filter 1 Filter Functian Flat Track Ratio 1 000 Frequency 100 259 Meter Filter Filter Functian Fiat Track Ratio 1 000 Frequency 100 259 Most of the functions in this dialog are clearly labeled and self explanatory They are covered in detail in a later section Data Curve Graph Name 1 P25 at 1M Freq SPL Phase Lo Hz HiFreq Hz Points Directio 100 000 1 000k 100 Dn C Up Contra Osc OnOff FTU Pulse Gate Time Calculator Gate Timin Dec OF 200 0000rn Sec Ose On 50 0000 Sec Meter Di 50 0000 Sec Meter On 100 0000m Sec To turn the OSC output On Off there is a button in the lower left corner of the dialog This same function is also available in the Analyzer Menu and toolbar LMS 4 1 33 User Manual Getting Started S 51MS Sample lib Graph Analyzer Process Hew Open Reopen Save Gaves Revert Load QuickSet File Save Duick Set File Print Editor Preferences Exit 34 Ctrl M Ctrl 0 k Ctrl 5 Ctrl P Chapter 3 3 2 Using QuickSet Files The Analyzer Parameters dialog provides the capabil
263. references dialog and disable Automatic Labels Scale Parameters x V ertica Inductance Capacitance Excursion Velocity Acceleration Time Phase SPL Voltage Current Impedance Ratio Axl Hang Division Linear 200000 Major 10 Log dB Min 20 0000 ri irit dB i Bipolar Per Div 10 000 t Positive Ok lenibus Zero Ret 1 0 Harizanta Frequency Time Angle Axl Hang Division Linear Max 40 DOCOK Major fo i L 9g Min 10 0000 Minor 2 Plo Hect Unit Polar Prefix El pez E 207 Scale Menu Chapter 9 Frequency Time Ange Axl a Division Linear 4q 0000K DOCCK Major PE 100000 Minor f2 Pla iv Rect Unit Frefi Polar Es FETE em Sot Horizontal Frequency Scale This is one of the most commonly used scales in the program You can choose Linear or Log axis rectangular or circular plots and the range of frequency Nyquist type plots are produced by using the circular selection For Log scales the Min Range value must not be zero Linear scales can use any value for the Lo Hi frequency parameters However Log scales will have the Lo Hi frequency values rounded towards their nearest major division This produces Log grids with much better readability For example entering a value of 23k would be adjusted to 20k You could choose 20k or 30k for the end frequency but fractional values
264. requency For example a woofer might be tested in the range of 20Hz to 200Hz This is not to say that the full range need be covered Indeed sweeping the device over a portion of the range may be sufficient For the above woofer a sweep range of 10Hz to 100Hz would probably provide good results In the case of a tweeter or high frequency transducer the resonance frequency might be 400Hz or higher In this case sweep the device from 200Hz to 2kHz The number of data points is largely a matter of personal choice Anywhere from 10 to 100 would be typical Since this test is making measurements close to the noise floor DNS Did Not Settle messages may be a nuisance Using the HiSpeed mode will avoid this problem Rub and buzz testing can require a lot of experimentation to acheive the best results There is almost always a trade off between sensitivity and false readings There are many parameters which can be and may need to be adjusted Different results can usually be obtained by testing at different levels In some cases a low drive level may work best while in other cases a higher drive level willimprove results A trial and error approach is the most practical with many samples to establish the PASS FAIL limits required for production 326 LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications 16 3 Electrical Rub amp Buzz Testing Developing a method and procedure for rub buzz testing is largely exper
265. rforms curve comparisons The tool button as shown above on the Processing toolbar can also be used to activate this item The Curve Compare dialog is primarily intended for production quality control applications although it can be used in any circumstance This dialog has two different types of comparisons which it can perform Absolute and Relative Curve Averaging Curve Compare Either method will give a PASS FAIL response after the test If the test fails another dialog will appear stating the problem frequency If the test passes only a confirmation beep is produced and the dialog closes normally The Absolute test uses two other curves as Maximum and Minimum limits If the curve exceeds either of these two bounds the test will FAIL The Relative test can be used in two different ways It can make a comparison to another curve or it can test for relative flatness Both test methods can be limited to a range of frequencies less than that contained in the curve entries The library curve list boxes provide selection of the library curve entries for the comparison opera tion These special list boxes show the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Curve Compare Metho Absolute Test Parameter Lo Freq H2 10 0000 Hi Freg H2 5 00006 14 ScalarAime Freq SPL Phase
266. rocedures must be maintained One of the most important is how the speaker is held For the delta mass method it is not sufficient to simply hang the speaker in air The forward motion of the cone mass will cause a reverse motion of the frame assembly This can and usually will affect the shape or resonance frequencies of the Impedance curve Clamp the Speaker The speaker must be rigidly held in place to prevent the frame from moving against the cone motion One method is shown on the following page for clamping the speaker between two tables or benches Another method would be to use a large board as a baffle and mount the speaker in the middle of it Here two tables of similar height are positioned so the speaker rim will slightly overhang onto both table edges Two C clamps are then used to clamp the rim to the tables The tables must be sufficiently stable that they themselves will not vibrate significantly Otherwise other resonance bumps will result This method allows for a free air environment since the tables do not block the rear sound from reaching the front It is important that the speaker have plenty of open area around it Many other methods of clamping the speaker can certainly be used effectively provided these basic requirements are met 315 Impedance Applications 316 Chapter 15 Table Clamping of Speaker for Testing Sweep the Impedance Curves Once the speaker has been clamped an impedance curve can
267. s e If a line contains additional columns of data they are ignored e If a line does not contain enough columns zero values are assumed for the rest Numeric real formats of both scientific and engineering are supported Note It is best if comment lines start with a special character such as 1 The name of the file to import may be either entered in the edit box or selected with Browse You can also edit the file with your external editor by clicking on the Editor button Once the file is selected it is loaded into the built in viewer of the dialog The viewer also provides the editing capability of the local file copy When you click the Ok button data is processed from the viewer window and not the file itself This allows you to edit the copy of the file held within the viewer without changing the file itself If you wish to change the file use the Editor button 163 Utilities Menu 164 Chapter 8 Import Curve Data x Horz Data Column 1 Left Wert Data Colurnin 2 Fight Vert Data Column 3 Freg Prefis fimp tv LinLog dB Phase Lin Log dB Polar Freq Hz Units dB Ref Prefix Units dB Ref Prefix Units Curve Entr Special Pracessin 11 C13 Again Freg SPL Phase Skip First Data Column File Pat C Program Files xport SAMPLE MB Ww GDT Browse Editor File Viewer 560 Lines LMS Version 3 50 Export Graph Data Table GPT Format Feb 10 1993 Wed 7 z8PM Curve Library
268. s of each curve entry To enter or edit the name of a curve press the Name button An edit box will appear for entering the curve name When your editing is done click Name again to save your changes or Cancel to abort them In many cases you may wish to display various curves on the graph Clicking the Graph button will show the selected curve on the graph by itself When you are ready to start a sweep use F9 the sweep tool button or the Sweep item on the Analyzer menu LMS 4 1 User Manual Chapter 6 LMS 4 1 User Manual Analyzer Menu Control Panel Three buttons are shown on the control panel The first button Osc On Off will toggle the oscillator On Off This can also be done from the Analyzer menu toolbar or by using the shortcut key F10 This only pertains to static measurements since the oscillator is automatically turned on during a sweep The TTL Pulse button will produce a single pulse at the TTL output The Gate Time Calculator button will open another dialog for setting up the gate timing values This was previously described 87 Analyzer Menu Chapter 6 88 LMS 4 1 User Manual Chapter 6 LMS 4 1 User Manual Analyzer Menu 6 2 Sweep Start Stop Analyzer Analyzer Ex Parameters Sweep Start 5top a p sc SENT i F10 BH ES hu ad li ALC Meter Microphone Setup Interface Macro Run Calibration The Analyzer Sweep Start Stop menu item will begin or end
269. s the binary modules used in the pro gram These include the main EXE and any other special DLLs called by the program About Modules This listing allows you to examine the date codes and About Program version numbers of each module This can be important for future upgrades and diagnostic troubleshooting About Modules LMS LINEAR SYSTEM indes peson Toss LMS EXE Loudspeaker Measurement System 4 0 0 231 020322000 2 LMS LOS DLL Optimization Engines 06 12 2000 3 LMS FFT Convolution Hilbert Transforms 06 12 2000 4 LMS LOF DLL Vector Code for Logos 05 26 2000 5 LMS L S DLL Global Optimization Systems 05 26 2000 LMS 4 1 247 User Manual Help Menu Chapter 12 248 LMS 4 1 User Manual Chapter 12 Help Menu 12 5 About Program Help The Help About Program menu item will display a Canton F dialog which gives a wide array of different informa This includes the user name and serial number Glossary hardware system operating system and program ver sion About Modules About Program A URL 1s also provided which will launch your web browser and take you to the manufacturer s web site An Email address is also provided which will launch your Email application and begin a message to our technical support department The last function generates a text file which contains all of the information which might be involved with tech nical support is
270. s the input curve is shown in Blue and the model simulation is shown in Red The resulting parameters for the Standard model are simply the Revc value of 3 30 Ohms and the Levc value of 0 347mH The model simulation does not match the impedance curve very well at all This is due to the complex nature of the magnetic system within the speaker Both AC resistance losses and inductance are a strong function of frequency The Standard model does not provide any capabilities to represent this behavior The following page shows the parameter and simulation results for the LEAP model In this case the simulation matches both the magnitude and phase much more closely then the previous Standard model The resulting parameters are Revc 3 30 Ohms Krm 2 34 mOhm Kxm 8 98 mOhm Erm 0 762 Exm 0 705 The K and E parameters provide a frequency dependent representation for both the AC resistive losses and the inductive reactance These relationships are much closer to the actual behavior of the real speaker LMS 4 1 User Manual Chapter 7 Processing Menu Parameters and simulation results for the Standard Model Blue curve is the input and Red curve is the simulation Note that the magnitude and phase poorly match the original data Speaker Parameters 45 Blocked Woofer Freq mp Phase mp Phase E Inf Baffle ej 000 58 000 mm wm ow fuz 46 SpkiMo
271. se frequencies MIC 1 Meter LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications 14 5 Near Field Measurements The measurement methods discussed in the preceeding sections are known as far field measurements This is because the microphone is far enough away from the source that the sound radiation at the microphone is spherical This means that the response drops by inverse square law as distance increases If the microphone is moved to a very close distance near the piston surface of the source the radiation becomes a pressure field This is known as the near field By placing the microphone closer to the source boundary reflections are eliminated since the reflection amplitude relative to the direct amplitude will be much smaller Typically a microphone may be 1 or 2 meters away from a source measuring 90dB of direct SPL With boundaries at 2 or 3 meters away serious reflections would be produced since the reflection levels would have similar levels at 80 90dB How ever when the microphone is moved closer to the source the direct level increases dramatically while the reflection level does not significantly change The characteristics of the near field region are quite different than those of the far field region In the far field a doubling of distance from the source will decrease the level by 6dB In the near field region this does not occur The pressure remains constant regardless of changes in distance
272. sed for the preview curve and LL UR markers Using the Capture Dialog The first step is to load the desired file with the Load File button Once the file is loaded you should probably next go to the Horizontal and Vertical panels to select the type of graph and the frequency axis The two LL UR reference coordinates must now be defined Click the Lower Left button and then select a reference point in the lower left corner of the graph A small LL marker will be placed on the image Next do the same thing for the upper right marker A UR marker will be placed on the image The two graphics below illustrate this process LMS 4 1 User Manual Chapter 8 Utilities Menu Once the two reference point coor dinates are defined go to the edit ing fields for the frequency verti cal parameters and enter the ap propriate graph values at these two locations Now the color representing the curve must be chosen Click the Curve button at the top and then select a point somewhere along the curve as shown below Forsome images there may be many different shades of color around the curve The curve may have soft edges Selecting different points on the curve may pick slightly dif ferent colors The last step is to choose a color matching tolerance on the slider For a reasonable starting value choose 10 The proper choice for this parameter depends on how much color purity is in the image or color noise Yo
273. ser Manual Macro Programs 13 3 Creating Macro Programs The macro program must first be created with a text editor either within LMS or by using an external editor Any typical text editor can be used or even a word processing program The file format is conventional ASCII lines of text However the LMS software contains a built in Utilities Macro Editor which is ideally suited to this task The file name must be given an extension of MAC The LMS system only recognizes macro program files with the MAC extension After the program file has been created with the editor you should place it in the LMS Mac folder or some other folder for your project Note If you will be using a word processing program make sure to export save the file in a straight ASCII text format The actual proprietary file format used by word processing programs is normally not a simple ASCII file but contains imbedded commands which the word processing program uses The LMS interpreter will not understand these commands and will flag these lines as unknown macro state ments See your word processing manual for specific instructions about saving ASCII text files 255 Macro Programs Chapter 13 13 4 Program Structure and Syntax The structure of an LMS macro program is very simple Since most people have some familiarity with the BASIC language a similar approach was selected for the LMS language Also the LMS interpreter is similar to that of a BASIC
274. ses the letter E as so 10 assumes that 1f the E character 1s the last character 1n the number it 1 18 1S treated as the exa multiplier 107 If additional numeric values fol low E then itis treated as scientific To avoid confusion component values are never displayed with the type of units For example a capacitor value of 2 4f means 2 4 femto 2 4E 15 It does not mean 2 4 Farads Itis assumed that the user already knows what the units are for the given component e g Ohms Henrys Farads etc Please keep this in mind when you enter component values you do not need to add the units 23 General Features 24 Chapter 2 Entering Numerical Values Floating point numbers can be entered in any of three forms real number format scientific format or engineering format Examples are 2400 75 real 2 40075E3 or 2 40075D3 scientific 2 40075K engineering A floating point number must not contain spaces Therefore do not place spaces between suffixes orother digits Note that the scientific format supports the use of either the E or D character to separate the exponent Lower case also In many dialog locations throughout the program the entry of the numeric values is monitored and checked for range violations For example many parameters will not permit either negative or zero values If you enter such a value in one of these locations it will be automatically corrected
275. set Analyzer Parameters dialog and note the changes 3 Mac set 8 Spl set ET zImp2wire se from the previous SPL setup la Mac3 set la Spl_gate set EJ Polrlk set a la set la Wwb set a Rub set Z 1 set Analyzer Parameters AH A Oscillato Mad Meter Filter 1 Output Level EU Hi Speed Data Filter Function Fiat Precision Data File name Zimp2wire set Frequency 448 813 a Hz F Track Ratio 1 000 E Gatin Files of type Set Files set dau ei Frequency 448 513 Meter Filter Filter Functian Fiat Track Ratio 1 000 Frequency Hz 448 513 Mete Data Impedance Ohm Source Line Output Freq 0000 Hz LoFreq Hz HiFreq Hz Points Directio 10 000 40 000 40000k Dn Up a Contra OnOff FTU Pulse Gate Time Calculator Gate Timin Osc Off 20 ant Sec Ose On 20 0000m MeterDly 5 0000m Sec Meter On 10 0000m Sec Since we probably do not wish to overwrite the previous SPL data curve the first thing we should do is change the data curve selection here to 2 If you wish you can also assign a name for the curve by clicking the name button If you have your speaker connected as previously described you can now take a static Impedance measurement simply by pressing the Osc On Off button You will see the i
276. sfer functions with prescribed magnitude response but different group delay characteristics For example a normal analog minimum phase type filter response could be generated in the target system and then a custom group delay curve created using the Curve Editor The new group delay response could be a simple flat line for linear phase This transform can then produce a new phase curve representing that linear phase response The group delay curve is specified as Left vertical data in the Source Curve entry The transform will write the resulting phase response to the Right vertical data of the Result Curve entry Generally you will have the magnitude that you wish to keep already in the Result Curve entry The curve list boxes provide selection of the library curve for or the operations These special list boxes shows the type of Source Curve with Delay Data 13 2kHz BandPass Result Curve for Phase Data 23 Result 413 G12 Cancel Help LMS 4 1 User Manual data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Freq Freq atin Phase 121 Chapter 7 Processing Menu below demonstrate a linear phase example A group delay curve The graphs was created using the Curve Editor which is merely a flat line of 40mS After the transform is run the resulting phase is shown below
277. sing this command Example 100 INC X 263 Macro Programs 264 Chapter 13 E INPUT message variable Input an integer value assign to var The INPUT keyword is used to allow the operator to respond to a question and enter a response This function 15 limited to integers The message text is written on the command line with an entry response field and waits for the operator to enter a number and press ENTER The message text must be in double quotes The command line is always automatically cleared before placing the message text You do not have to use COMLCLR first Also the command line will be cleared after the response The variable parameter is a label you wish to assign the response value to The variable parameter must be defined with the VARLABEL command before using this command This command is very useful for making program selections or choices After this command one or more IF statements would probably be used to handle the selection Example 100 INPUT Print Graph l yes 0 no X B INTCAL Runs the Internal Calibration Routine The INTCAL keyword is used to call the Internal calibration routine for the LMS system This command is intended for factory use as it is not typically required for regular operation Example 100 INTCAL B LEVEL entrynumber octave Smooths a curve using octave width This keyword is an alternate for the SMOOTH command Example 100 LEVEL 12 0 5 BLIBLIST Displays the Curve Library
278. sues The file SYSCONFIG TXT is written to the program directory This file may be requested when providing assistance It can be attached to an Email or faxed About Application Application Program Operating System Hardware System Mon 4 37 pm Processor Architecture Intel Time User Manual s lr Version 4 0 0 231 p Jy 1 03 2000 2000 All Rights Reserved LINEARS SYSTEMS INC 9500 5 T ualatin Shernvood Tualatin OR 97062 USA Tel 612 9565 Fas 503 612 9344 http fan linear com suppartielinears com create SYSCONFIG TAT file Analyzer 10 Port 0000 Date Platform Version Build Service Pack Total Virtual Memory Avail Virtual Memory True Type Fonts Adobe Type Fonts Windows Path COMCTL32 Version COMCTL32 Date File System Person 11 111 Jul 3 2000 WinNT 40 1381 Service Pack 5 2046M B 1388MB 1 8 345 4 72 3612 1702 0429 1999 Processor Count Processor Vendor Processor Model Total Disk Space Avail Disk Space Total Physical Memory Avail Physical Memory Total Paging File Avail Paging File Video Harz Video Vert Video Colors Company 111 SM 123455 1 Genuinelntel Pentium ll M5 2039M B 41MB 255MB 171MB Bor hE 456MB 1024 Pixels Pinels 32 Bits 249 Help Menu Chapter 12 250 LMS 4 1 User Manual Chapter 13 Macro Programs Macro Programs 13 Macro Running Test ESC to Abort Lin
279. supported as well as search and replace operations Furthermore it provides the ability to perform syntax checking on the macro script program and can also be used to run the macro Macro Editor Test Mac Ele sc File Edi Search Operations Help Title LMS Macro test Program for Interpreter Development Date 11 18 91 Author C Strahm Description This program is for testing all of the macro statements used in the LHS language 65 VARLABEL X 78 WORKCLR 88 COMLCLR 118 COMLHMSG Loading Library File LHS LIB S 128 LOADLIB SAMPLE LIB 136 DATACURVE 15 146 GRPHCURVE 15 142 WORKCLR 143 COMLCLR 158 WORKMSG Test Program for Macro Development 168 WORKMSG 2222222z222 2z2 2z2 22 2 2z2 2z2 2 2 2 2 2 2z2 2z2 2 2 2 2 2 z2 2 2 2 2 178 VORKHSG Selection Menu 1 Run Sweep Test Sweeps 188 WORKMSG 2 Print Graph 198 WORKMSG 3 Level Curve 288 WORKHSG 4 Compare Curves 218 WORKHSG 5 Name Curve 228 WORKHSG 6 Ratio 15 16 18 238 WORKHSG 7 Delta 15 16 18 246 WORKHSG 8 Graph Display 258 WORKMSG 9 Exit Program n 268 WORKMSG s 2sssessesscessesessssssesessssesssssssssss 278 INPUT Enter Menu Selection Number 1 9 X Font Row82 Col 1 C LMS MAC Test Mac 7 LMS 4 1 193 User Manual Utilities Menu Chapter 8 search Operatior Mew Ctri M Undo Find Ctrl F Macro Editor F1 Open Redo Replace Ctri H Macro Comman
280. t if you have a meter read the voltage and enter the value If you do not just hit Enter to keep the preset default value The system will conduct several tests and then ask you to connect the Output line to the Input line Plug these two XLRs into each other and hit Enter Next the system will ask you to connect the Output line to the Mic Input Unplug the Output from the previous balanced input and connect it to the Mic XLR and hit Enter The operation will end shortly after the Mic Input test Any errors will be reported to the dialog If you do receive error messages repeat the external calibration again You may have connected the wrong lines or did not connect them at the right time Remember to follow the prompted instructions in the dialog Analyzer Calibration x Jippe Farameter Under Tes TETE Full Scale Output Voltage rme fe External Enter LineOut Click Ok when done 25 Abort Result External Calibration LHS port UZIlF 13 Installation 14 Chapter 1 1 8 How to use the Manuals Nobody likes to read manuals and it is also true that most people do not enjoy writing them We know that you would like to start using your new LMS system without having to read anything but a little knowledge can go along way For this reason we recommend that the following chapters be read in total Chapter 1 Installation Chapter 2 General Features
281. t 1M P25 at 1M 180 K je 23 196 Hz 83 974 dBSPL Let Mouse Cursor Dragging Hand Vertical Scroll Bar LMS 4 1 User Manual Chapter 2 LMS 4 1 User Manual General Features 2 Numeric Entry amp Formats The dynamic range of numeric values can be extremely large To handle this wide range efficiently LMS makes extensive use of engineering notation These are single character multiplier suffixes which appear at the end of a numerical floating point real number value We are all familiar with the common usage of engineering notation for common components such as a 10K resistor or a lu Farad capacitor Here the represents 1E 3 and the represents 1E 6 While these are common SI suffixes that will be familiar to most users there are other SI suffixes that are less common The full list of supported SI multipliers are as follows Note that in virtually all of the suffix chars the following conven tion is used upper case is used for Name Value Suffix Name Value Suffix multipliers greater than unity and lower case is used for multipliers smaller than unity The only ex ception is the kilo suffix where both cases are supported K or K CINE pio 107 p Use of the exa suffix E can lead to confusion since the standard scien pea 107 tific notation u
282. t Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Input Deg Output Freq Output Freq Output Freq Output Freq Output Freq 90 deg B2 5 deg T5 deg 67 5 deg 0 deg 52 5 deg 45 deg 37 5 deg 30 deg 97 5 deg 15 deg 105 deg deg 112 5 deg All OFF 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 0 40 0E Hz 10 2 40 0E Hz Standard 180 180 0000 180 0000 172 5000 165 0000 157 5000 150 0000 142 5000 135 0000 127 5000 2 Q000K 10 0000K 20 0000K 40 0000K Standard 360 180 deg 150 deg 172 5 deg 165 deg 157 5 deg 150 deg 142 5 deg 135 deg 127 5 deg All OFF 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz 10 2 40 0E Hz Standard 180 e m SFL SFL SFL SFL SFL SFL SFL SFL SFL SFL SFL SFL SFL Chapter 8 The dialog view shown here illustrates the setup for the in put curves and the lower dia log below shows the output curves The order for some of the input curves was mixed The Deg values for each input curve were entered to match their locations The frequency values for the output curves were entered as well for the last five entries When the Ok button is clicked the polar curves are g
283. t the Sweep Data Curve Entry The DATACURVE keyword is used to select the curve entry in the library that will hold the next sweep data The entry number parameter must be an integer through 50 Example 100 DATACURVE 7 LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs B DBLIN entrynum code Convert dB curve to Linear Curve This command is now obsolete under LMS version 4 Example 100 DBLIN 11 1 DEC variable Decrement variable The DEC keyword is used to decrement subtract one from the variable The variable parameter must be defined with the VARLABEL command before using this command Example 100 DEC X B DELTA entrynumA entrynumB entrynumR SUB A B R This keyword is an alternate for the SUB command Example 100 DELTA 11 12 15 DIV entrynumA entrynumB entrynumR DIV The DIV keyword is used to produce a ratio result curve from two other curves AII parameters must be integers and between 1 through 50 This is the equivalent of dividing one curve by another or subtracting their magnitudes in dB Example 100 DIV 11 12 15 B END End of Macro Program The END keyword is used in all programs to denote the end of the program It is normally on the last statement line More than one END statement can be used Whenever an END statement is executed the program will end Note pressing ESC or CTRL End will produce the same result Example 100 END ERBEEP Error Beep Sound Th
284. t to 24dB Oct and 24dB Oct respectively The upper graph shows the original data in Blue and the corrected data in Red The lower graph shows the phase as produced from the Minimum Phase Transform for both the original and corrected curves SPL vs Freq SPL vs Freq 146 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Realign Curve Averaging Curve Compare Data Transfer x Sourc Eime Data Left 47 Right 18 C13 Packed Freq Phase 23 C13 Packed 5 2 LMS 4 1 User Manual cms Processing Menu 7 10 Data Transfer P E E ES AMHR EJ The Processing Data Transfer menu item will open a dialog that allows you to move individual vertical data arrays from one curve to another The tool button as shown above on the Processing toolbar can also be used to activate this item A library curve entry actually contains a pair of data arrays one for the Left vertical parameter and one for the Ri
285. t will show a 0 to 100 display when an operation is in progress System Message The final large panel will display a system message as needed during program operation 236 LMS 4 1 User Manual Chapter 11 LMS 4 1 User Manual Toolbars Menu 11 5 ToolBox Toolbars Show All Hide All v File Graph w Analyzer v Processing wf bilities Scale VE v ToolBox ToolBox The ToolBox is a floating window which contains a control bar or tray This enables multiple toolbars to be dropped into the control bar and moved as a group If the ToolBox contains no toolbars the size is reduced to a minimum as shown below As toolbars are dragged and dropped onto its control bar the size is automatically in creased Using the ToolBox provides a means of creating a floating toolbar array rather than the fixed locations provided at the top and bottom of the screen There are countless ways that the toolbars can be arranged in the program When the ToolBox is hidden any toolbars contained within it remain checked on the menu and the ToolBox is unchecked If you cannot find a toolbar remember to check the ToolBox to see if it is contained there ToolBox Ep v d 50 7 EECEEEPEEEEETET amp B ILE gf IRRBBBBE 4 4 237 Toolbars Menu Chapter 11 238 LMS 4 1 User Manual Chapter 12 Help Menu Help Menu 12 Help C
286. ta File 163 9 2 Export Curve Data File 165 9 9 Export Graphics 10 FIG as nan ie 167 8 4 Export Graphics to Clipboard _ 173 8 5 Gue RR UEM 175 eM soo MERO 181 Ma Macro srren 193 0 0 MDF Toro 195 9 9 Polar CONVENON eiat cb ERG 199 Chapter 9 Scale Menu 205 m 207 SX Ur 213 SAP c 215 SR MB MU 217 LMS 4 1 vii User Manual Contents Contents Chapter 10 View Menu 10 1 10 2 Zoom In Zoom nn Zoom TX 74 2X J AX 1 8X 10 3 Redraw Chapter 11 Toolbars Menu 11 1 11 3 SHOW PRN e ina tint ceu uto 11 2 Hide All Menu ne Re 11 4 Status Bar 11 5 ToolBox Chapter 12 Help Menu 12 1 COMENIS PTT 12 2 Index 12 3 Glossary 12 4 About Modules 12 5 About Program Chapter 13 Macro Programs viii 13 1 13 2 13 3 13 4 13 5 13 6 13 7 13 8 13 9 Macro Programming Running Macro Programs Creating Macro Programs Program Structure and Syntax Rules Debugging and Error Reporting Planning a Macro Program Macro Co
287. tage at the speaker s terminals the cable and shunt resistance will be automatically removed It is important to measure the speaker voltage directly at the speaker terminals Keep the speaker wires from the VI Box to the load as short as possible The sweeps should be taken in pairs to ensure that the level is not changed between the voltage and current sweeps The figure below shows the current curves Now the impedance curves can be produced The DIV process is used for this purpose Each voltage curve is divided by the current curve for each drive level After a Vspk curve is divided by the Ispk curve the ratio curve produced is impedance Current vs Freq FA E ERE 3s EUR ON S EEE HE TH N E LMS 4 1 User Manual Chapter 15 Impedance Applications The impedance results are shown in the graph below Three curves are displayed for the three power levels of 1 10W IW and 10W As can be seen in these curves the region near the port tuning changes slightly with level Also the position of resonance frequencies of the low peak move If a 100 watt curve had been run there would be an ever increasing amount of change At the bottoms of the impedance curves there is a noticeable rise in impedance for the 10W curve This is due to heating in the voice coils causing an increase in the copper resistance Another more dramatic example
288. ters 5 Start 5t F3 tk FIO BOOB 4 0 90 ALC Meter Microphone Setup MM The Analyzer Macro Run menu item will open a dialog Macro Run which allows you to choose a macro file to load and run The Se tool button as shown above can also be used to activate this item As soon as the macro is loaded it will be immediately run At that time the Macro Running dialog will open and remain on the screen To create macro programs see the chapter on Utilities Macro Editor Open Macro File HE Look in EJ Mac v E Expnaise mac Spltest mac Test mac Macro Running Test ESC to Abort Macro Running Test Mac ESC to Abort Files of type Macro Files Cance 230 WOREMSG 7 Delta 15 16 18 E Work Are Test Program for Macro Development Selection Menu ilj BRun Sweep Test Sweeps 4 Print Graph 3 Level Curve 4 Compare Curves 5 Name Curve 6 Ratio 15 16 18 Parameter LMS 4 1 99 User Manual Analyzer Menu Chapter 6 6 8 Calibration Analyzer Analyzer Ea Parameters 5 Start 5t F3 E UI E F1 4 g ES rf el ALC Meter M cu The Analyzer Calibration menu item will open a nterface dialog which performs testing and alignment of the Calibration application software to the LMS hardware The tool button shown above can also be used to activate this item The LMS
289. the cursor over each of the buttons will display a hint which describes each button Scale and Smooth Buttons A group of scale controls for the vertical value are located on the right side of the toolbar These operate in a similar fashion to the vertical graph controls in the Scale Parameters dialog of the main program The smooth button will cause the currently selected points to be smoothed Cume 8 P25 1M Tails SPL Phase Points 500 Read Write Read Write Curve The controls necessary to input output data to the Library Curves are located on the lower left of the status bar The list box is used to select a single Library Curve for reading or writing The Points parameter allows you to choose how many nodes you wish to create when reading a Library Curve When the Read button is clicked the edit curve nodes of both vertical data arrays are calculated from the selected Library Curve entry When the Write button is clicked Library Curve data is created from the edit curves of both graphs The frequency range of the Library Curve will be the same as the displayed frequency range with the number of data points setto the number of Points The Library Curve is enabled for display and given the name Curve Editor Cursor Readouts 411 2545 Hz 74481 Dhm As the cursor is moved around the graph the frequency and LMS 4 1 User Manual vertical value will be displayed in the lower right corner of the status bar 187 Ut
290. the points between the test frequency limits In this example the test was from 20Hz to 5kHz and passes the tolerance of IdB If the frequency est Parameter 22 Lo Freq Hz 20 0000 HiFregiHz 5 0000K range is increased the test fails at around 7kHz 14 ScalarFims Freq SPL This method is useful when you wish to compare Curve Compare Metho C Absolute Relative R a single curve measurement for basic flatness Max Limit Curve 15 Max Limit Freg SPL Phase Since the mean level is self adjusting based on the Min Limit Curve 16 Min Limit SPL Phase test curve itself this method is very desirable ee when the absolute level is not important and only Tolerance dB 1 0000 Reference Relative Flatness the relative flatness is required Reference Curve ScalarHms Smoothed SPL Phase zl By using the divide operation prior to comparison __ any non flat type response also be tested for relative match to a reference shape irrespective of absolute level P SPL vs Freq 10 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K 160 LMS 4 1 User Manual Chapter 8 Utilities Menu Utilities Menu 8 Utilities Import Curve Data File Es A Export Curve Data File E Tl Export Graphi
291. tilities Menu 8 2 Export Curve Data File Import Curve Data File Export Curve Data File Export Graphics to File Export Graphics to Clipboard Curve Capture ner The Utilities Export Curve Data File menu item will Editor open a dialog which exports text file data from library curve entries The tool button as shown above on the Utilities toolbar can also be used to activate this item Macro Editor MOF E ditor The type of data and the units to be exported are controlled entirely by the current parameters in the scale system In other words the data is exported in exactly the same units as it is currently being viewed on the graph For example if a curve contains voltage data and is currently being displayed on the graph in dBm units the data 1s therefore exported in dBm units If it was viewed in Volts it will be exported in Volts This allows the user to automatically translate and export data into whatever units are desired simply by displaying the data in the desired units on the graph This is controlled by the Scale Parameters dialog The export dialog displays the units for the data curve that will be exported The curve list box provides selection of the Hore Range Left Vert Right Vert library curve for the operation This special list box shows 102400kH dsPL D the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red
292. tion The minimum phase transform is now run on each of the three ranges After this SPL vs Fre Original Driver Curves with Crossover Networks SPL vs Fre dBSPL s f e N 10 Hz Driver Curves with Tail Corrections 299 LMS 4 1 User Manual Chapter 14 SPL Applications The resulting curves for the various ranges are now shown in the graph below This graph will be very difficult to read since the delay on the woofer and midrange cause the phase to rotate large amounts at high frequencies The curves are now ready to be summed together The only question that remains is whether to sum these curves together in phase or out of phase If we knew what the wiring and polarity was on each of the transducers the answer would be easy but in this case trial and error will be used SPL vs Fre RP ne ER P EE GER el FE REET ded E Driver Curves with Minimum Phase and Delay LMS 4 1 User Manual 300 Chapter 14 LMS 4 1 User Manual SPL Applications The graph below shows the woofer and midrange curves summed together both in phase and out of phase This is done by using the ADD or SUB operations From this graph it is clear that the correct response is produced by using the SUB operation The curves must be summed out of phase If the curves are summed in phase a large dip is produced in the response at the crossover region of 250Hz Using the combined result from the
293. tions These special list boxes shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Inverse Fast Fourier Transform Parameter Linear Frequency Points 2046 vi Source Curve Frequency Domain D ata 8 P25 1M Tails Freq SPL Result Impulse Curve Time Domain Data 30 Impulse P25 1H Tails Time Wot Phase Time Domain Data Result Step Curve 31 Step P25 1M Tails Time Wot Phase 126 LMS 4 1 User Manual Chapter 7 Processing Menu The three graphs below show a sample frequency domain curve transformed into the equivalent time domain Impulse and Step response curves The number of frequency data points used here was 2048 EN SPL vs Freq a a Voltage vs Time HA LMS 4 1 127 User Manual Processing Menu Processing Unary Math Operations Binary Math Operations Minimum Phase Transform Delay Phase Transform Group Delay Transform Inv Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction D ata Transfer Data Splice Data Realign Curve Averaging Curve Compare 128 Chapter 7 7 7 Fast Fourier Transform P E ES ES AMR
294. to your project and problem please include a copy of your design files with the necessary data so that we can reproduce your problem This is only possible if you are communicating via an electronic means such as Email or uploading files directly to our web site 3 If the issue regards error messages from the program please include an exact description of the error message and or address information that the program reports 4 If there are specific steps involved to reproduce the issue please note these exact steps required so that we can reproduce the problem Technical support hours are Monday Friday 9 00AM to 5 00PM Pacific Standard Time IV LMS 4 1 User Manual Contents Chapter 1 Installation 1 1 1 System Requirements esee 3 le OOt Ware Insrallatlolt e Eg 4 1 3 Hardware Installation 0 020 01 5 1 4 Interface Cable Installation 7 1 5 Starting the Program a 10 1 6 Microphone MDF Setup serein reed Eo E EY e dee E Eve 11 1 7 Analyzer Calibration uice taste eee eda aes 12 1 8 How to use the Manuals 14 Chapter 2 General Features 15 2 1 Tool Bars Tool Buttons amp Control Bars 17 2 2 Trackin oec AS ee 18 2 3 Zoom Progress Meter and Messages
295. trol bars will collapse down to minimal height This function along with the Show All can be used to locate toolbars which are off the screen and force them back into view An example with all of the toolbars removed is shown on the following page 231 Toolbars Menu Chapter 11 Z LMS Lms lib ciues f ER E LMS Sansz 232 LMS 4 1 User Manual Chapter 11 LMS 4 1 User Manual Toolbars Menu 11 3 Menu Toolbars Toolbars Show All Hide All Graph Analyzer ots zi E ToolBox B e ehib BIBa amp g e E AAD There are 7 toolbar items listed which correspond to the functions provided on other menu columns Each of these items will enable disable an associated toolbar The various toolbars are shown below Toolbars can be positioned
296. trols used for setting the two meter filters are identical These filters appear in series to the Meter and therefore control the characteristics of the measurement Each filter has four controls which can be adjusted the Filter Type the Osc Freq Tracking Enable the tracking frequency Ratio when tracking is on and the filter s fixed Frequency when not in the tracking mode These filters can be used whether or not gating is active The filters are simply used to control the frequencies where the meter will respond Using these filters allows various types of different measurements to be made or improve the quality of the testing by reducing noise bandwidths LMS 4 1 User Manual Chapter 6 Filter Type Analyzer Menu There are four filter types which can be independently set for each filter Each filter can be designated as either a Bandpass Bandreject Lowpass Highpass or Flat filter Characteristics for each filter type are as follows 5 Filter Shapes X 4 IY Bandpass amp Bandreje s NEP 20 Frequency 100 50 1k Hz 5k 10k 20k _ Bandpass Filter The Bandpass filters have a Q of 1 with a first order 6 dB Oct slope at both sides of the center frequency as shown below When both Meter Filters are set up as bandpass filters their combined slope is 12 dB Octave as illustrated below Both filters are typically s
297. u can now click the Preview button and observe the curve map ping For this example the curve was captured perfectly with atoler ance of 10 as shown here on the left If the slider is now changed to 5 color matching and the Preview button clicked again the resulting curve shows downward spikes The tolerance was too tight and the mapping fell through to a similar color below the desired curve LMS 4 1 179 User Manual Utilities Menu Ohm Chapter 8 Now if the slider is adjusted to 20 color matching the resulting curve shows upward spikes This is because the mapping process found pixel colors above the desired curve within the color tolerance The scanning was from top to bottom These examples illustrate the important use of the color matching tolerance It isatrial and error process to discriminate between color variations color noise and the color of the desired curve The selection of curve color adjustment of the color matching slider and use of the scan direction are all filtering mechanisms to pull out the desired curve from the background image Once you are satisfied with the preview you can click Ok to write the final data to the selected Library Curve entry In some cases where the image is very dirty you may not be able to remove all spikes from the captured curve In these cases you can use the Curve Editor utility to clean up the curve data afterwards The final captured curve is shown below Imped
298. ual Utilities Menu For curve color the color panels will be updated with the color of the pixel at the cursor location For the two coordinates a marker will be dropped on the image at the cursor location Reference Data Point Upper Right Lower Left Each of these two panels displays coordinate information based on two selected points on the graph image You must choose two points at opposite corners of the graph Lower Left and Upper Right Along with the X Y coordinates of these two reference points you must define the represented horizontal and vertical parameter values of the graph in the edit boxes The horizontal value is usually frequency but the vertical values will depend on the type of graph curve being captured Horz Data Left Vert Data amp Right Vert Data Understanding the use of these three panels is key to the proper import of external data Each panel corresponds to a data parameter Typically this may be frequency magnitude and phase If you have only frequency and magnitude use the phase selection for the Right Vert Data anyway The type of data and units prefix is critically important to define what it is you are capturing Always verify that the Units field displays the exact units that the image contains For example a voltage measurement could have a magnitude curve with data in units of Volts dBV or dBm The program treats each of these differently Linear Log would be used for Volts and the dB selection
299. ude curve data It is the equivalent of scaling the magnitude response You can also click the units button and enter a linear ratio if desired This operation is commonly used to move the magnitude data to a specific value perhaps at a specific frequency In the graph below the Brown curve was dropped 3 0dB so that the maximum level on the curve is OdB The result is shown in the Red curve SPL vs Freq dBSPL LMS 4 1 User Manual Chapter 7 Processing Menu Phase Offset This operation simply adds the numeric Deg value to the phase curve data It is the equivalent of shifting the phase response If the Zero check box is enabled the curve will be cleared to zero before the offset is applied This operation is commonly used to change the polarity of a curve by entering a value of 180 or 180 degrees However any other value can also be used for unusual effects For example a quadrature response can be generated by shifting the phase by 90 degrees In the graph below the Blue curve was shifted by 180Deg to reverse the polarity of the response The result is shown in the Red curve SPL vs Freq 00 500 1K 2K 5K 10K 20K 40K Hz 20 50 100 LMS 4 1 107 User Ma
300. ue as angle and Saturation as magnitude The vertical slider next to the wheel controls the Value parameter This is essentially the overall brightness of the entire wheel As the slider is moved the Value of the wheel will change between 0 black and 100 full color brightness 27 General Features 28 Chapter 2 2 9 Font Select Dialog A special button control is located on many dialogs through out the program which provides for special editing of font Font selection An example of such a button is shown here When you click the button a dialog will open for font selection Choosing a font and its size is completely up to the user Itis certainly possible toselectafontand orsize thatis too large forthe available space in the graphics However with a little experimentation you will quickly see what is possible and what will actually work The program positions the text items automati cally either left center or right justified By changing the size of afont you can easily see how the program will position the text Font Select TypeF ac TypeSiz x 352 Font Families AdobeT ype 24 0 aasparilla55i Geometr415 Md BT Giddyup Giddyup Thangs Gilde Bold Italic Underline Strikeout faill5ans Condensed faill5ans ExtraBald faill5 ans Ultra old 215 ans UltraBoldCondensed Goianas 51 Goudy Old Style RACATRIONMAHRYAREN I Show sample actual size
301. ue line on the graph is a far field measurement This is a far field measurement done on a ground plane At frequencies less than about 100Hz the correlation 15 excellent As the frequency increases above 100Hz the ground plane measurement shows more amplitude This is due to a number of factors 1 the ground plane measurement contains baffle board directivity 2 the near field measurement also lacks some of the directivity of the cone itself For low frequency measurements the near field method produces very good results This result curve could be spliced into a gated sweep at 100Hz to yield a full range curve m SPL vs Freq 110 105 100 95 90 85 7963 tj Hz 50 100 200 500 1K 2K 5K 10K 20K Woofer Port compared to Ground Plane 287 SPL Applications 288 Chapter 14 14 6 Gated SPL Measurements By using a sophisticated series of electronic timing LMS can make quasi anechoic measurements in reflective environments LMS gates out reflections by turning the meter on when the signal arrives at the microphone and then turning the meter off sometime before the first boundary reflection has reached the microphone The control of these parameters is solely the responsibility of the user Since the total ON time of the meter window is being limited in order to avoid measuring reflections there is also a limitation imposed in terms of low frequency response
302. ull complex valued data Once the phase data is constructed group delay and time domain data can also be produced using other transforms on this menu Operating the transform is relatively simple The most important factor is the selection of the frequency range In order for a minimum phase transform to produce accurate results all of the magnitude changes must be contained within the system frequency range The magnitude curve data should reach asymptotic response at the low and high frequency limits This means that the derivative or slope of the magnitude curve reaches a fixed constant at the frequency extremes Once the transform knows the asymptotic slopes at the low and high frequency limits it can properly integrate the entire magnitude response from OHz to Infinity Both Log or Linear frequency axis can be used but Log is the most common 117 Processing Menu Chapter 7 Parameters Parameter The Data Curve containing the magnitude data should be 29 Result 813 812 Phase selected first The Data Curve list box provides selection of Asymptotic Slope at Hi Freg Limit dB Oct 6 7463 the library curve for the operation This special list box Asymptotic Slope at La Freq Limit dB Oct 6 5550 shows the type of data contained in each curve Any curve Automatic fam impedance Tunes which is currently being displayed on the graph is denoted by 118 ES T Red
303. umber to export The file will be written to the LMS Export folder if no path info is included in the name An extension of TXT will be used if none is specified Make sure to enter a file name that contains legal file name characters Example 100 EXPORTFN 11 MEXPORTVN variable entrynumA Expost ASCII Data File VarName EXPORTVN keyword is used to produce a data file using an 8 character name produced from the variable value as the export file name The variable parameter must be defined with the VARLABEL command before using this command The first parameter is the variable from which to derive the name the second is the curve number to export The file will be written to the LMS Export folder with and extension of TXT Example 100 EXPORTVN X 11 MEXTCAL Runs the External Calibration Routine The EXTCAL keyword is used to call the External calibration routine for the LMS system This command is intended for factory use as it is not typically required for regular operation Example 100 EXTCAL LMS 4 1 User Manual Chapter 13 LMS 4 1 User Manual Macro Programs line GOTO line number The GOTO keyword is used ito make a jump to a different line number than the next line The line number parameter must be given Example 100 GOTO 60 GRPHCURVE entrynumber s Select Curves for Graph The GRPHCURVE keyword is used to select which curves are to be displayed on the graph The entry number parameters must b
304. und plane the SPL for the same microphone placement distance will be 6dB higher than the anechoic SPL level The only requirement for a ground plane measurement is a large reflective surface such as a parking lot or drive way with no obstructions for a radius of 20 30 feet or more The procedure is to place the loudspeaker on its side on the ground and then place the microphone on the ground in front of the speaker Ground plane measurements like anechoic measurements will have a rising character in the response caused by diffraction off the loudspeaker baffle board This occurs in the mid range region The increase in SPL is about 6dB the frequency being determined by the total area of the baffle If you are measuring a multi way enclosure with low mid and high frequency drivers the enclosure should be positioned on its side with the high frequency driver nearest the ground The microphone should be aligned on axis with the high frequency driver as well The off axis angle relative to the wavelengths of the mid and low frequency drivers will typically not be significant Many times it is a good idea to slightly tilt the enclosure downward toward the microphone The important goal here is to try to keep the microphone on axis with the high frequency driver The ground plane method is a very good choice and does not require any expensive or elaborate set up All that is required is a flat surface with some open area around it See the fi
305. undary Tmtr dly Treflection 4xTmic 5 Tmtr on Treflection Tdly Tosc on Tmtr on x 2 Tosc off 20mS default For the figure above the total reflection path time is about 9mS The meter delay time would be 9 2 8x4 5 4mS assuming a mic distance of 1 meter or about 2 8 mS The meter on time would be 9 4 5mS and the osc on time would be 10mS The units for the time parameters can be changed by the user There are also equivalent distance units provided as well based on the velocity of sound in air Gate Time Calculator Parameter 3atin Source to Mic Path Distance Osc Off 50 0000 SEC 3 0000 Ft oscon Sim Reflection Path Distance Meter 3 00 73m Sec 10 0000 Ft Meter On 4 347 5m ee by inverting the Meter On The setting of the time parameters can also be done much more simply by using the Gate Time Calculator button This will open another dialog which allows you to setup all the timing parameters by entering the source and reflection path distances Itis important to understand the effect that gating has on the low frequency response of a measurement The shorter the Meter On time the higher the low end cutoff frequency The low frequency cutoff can be calculated time I Tmtr In order for wide bandwidth measure ments to be made to very low frequencies it is obvious that the limiting factor is the measurement environment LMS 4 1 User Manual 83 Ana
306. urve Editor into an internal buffer An initial Save is performed automatically when the dialog is opened This item can be used at any time during editing to update the internal buffer with the latest parameters and settings Both of the edit curves are saved in addition to guidelines and scale settings A tool button is provided for this menu item as well Revert This menu item will restore all the previously saved settings and parameters of the Curve Editor An initial Save is performed automatically when the dialog is opened so the internal buffer always has at least the original data A tool button is provided for this menu item as well Cancel This menu item reflects the usual Cancel button found on a dialog window Using this item exits the Curve Editor dialog without saving your changes Using the Close button in the right corner of the dialog is equivalent Ok This menu item reflects the usual Ok button found on a dialog window Using this item exits the Curve Editor dialog and saves your changes You must select this item to exit the dialog and retain your changes to the edit curves 183 Utilities Menu She w Left Vertical Right Vertical Show Snap V Insert Liens Delete Cirl Dial Select All Ctri 184 Chapter 8 Graph Menu This menu contains the two selections of the currently active editing graph You can move to a different graph to edit each of the different sets of edit nodes for
307. us system messages Data will appear in these fields as required during program operation The Left Right buttons control which vertical data is to be tracked from each curve A curve contains a pair of vertical data sets Generally the Left is magnitude and the Rightis phase However virtually any kind of mixed data can be transfered and displayed on either side of a curve s data sets The preformatted graph chart is drawn on a true WYSIWYG artboard display Printing is performed with the exact same contents as is viewed on the screen Both precision Color and Black amp White printing and export are supported LMS Sample lib File Graph Analyzer Processing Utilities Scale View ToolBars Help Basmpe sSgseanBBABE d 5 4 100 SPL vs Freq 95 90 85 80 75 120 150 40 180 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 40K P 4 Re 1 P25 at 1M H 23196 Hz 83974dBSPL Left Right Zoom Level Progress Meter amp Messages 19 General Features Chapter 2 2 4 Graph Hot Spots amp Popup Menus There are a number of regions defined in the graph artwork that respond to double clicks with the left mouse button These are hot spots that will activate various dialogs depending on the region For example d
308. ve Editor is a very powerful utility for creating many different types of curves or for manually editing an actual measurement For more details on using the curve editor see the chapter Utilities Curve Editor 332 LMS 4 1 User Manual Chapter 16 LMS 4 1 User Manual Misc Applications Create Data File for Import Another method is to create a data file that can be imported into LMS This is a simple ASCII text file which can be created in any word processing program or text editor The data format is simply a set of data columns with possibly some comments The listing below shows the data file for the Max limit curve The first 7 lines with a at the beginning are comment lines where you can place any information you like about the file The form shown here can be used as an example The next 9 lines are the data as taken off the markings of the graph The three columns of data must be separated with one or more spaces and there must not be any spaces between the digits of either of the three values in each line The phase data is really unimportant for the Max Min limit purpose and zero values can be entered The frequency points picked were simply the most obvious Manual Data for LMS January 19 1991 Author C Strahm Max Limit Curves for Passive Network Test Datapoints 9 dB Levels Freq Hz Level dB Phase deg 10 2 0 0 50 4 80 4 150 0 250 5 350 6 650 6 1000 10 2500 30 End of GDT Fi
309. vel 76 865m v Hi Speed Data Filter Function Bandpass cables and plug the oscillator output Precision Data Frequency 1 008 uem F Track Ratio 1 000 cable into the amplifier being used Tae or Con Frequency Hz UUGE Meter Filter Filter Function Bandpass Track Ratio 1 000 Frequency Hz UGE For this example we will load the SPL SET file Locate and load this QuickSet file as shown below After the file is loaded view the contents of the Analyzer Parameters dialog Data Curve Graph Name 2h Freq SPL Phase Lo Freg Hz HiFreq Hz Points Directio 20 000 20000 0 E Dn Up TTL Pulse Gate Time Calculator Gate Timin Ose Off 20 0000 Sec Ose On 20 0000m MeterDly 5 0000m Sec Meter On 10 0000m Sec Note If you are not using Drive you will need to change to the drive you installed the program on LMS 4 1 35 User Manual Getting Started EIE Untitled lib Graph Analyzer Process Open Ctrl Reopen Save Ctri 5 Gaves Revert Load QuickSet File Save QuickSet File Print Ctrl F Editor Preferences Exit Ctrl Chapter 3 If the amplifier has level controls set the level to 1 4 to 1 2 open The LMS oscillator can be toggled OFF and ON with the F10 key Set the amplifier to produce a nominal sound level from the speaker This can be adjusted either by the amplifier volume control or by the L
310. vel The meter will only see or respond to the input during time Tmtr When a burst of sinewaves pass through a transfer function of unknown characteristics such as a loudspeaker the leading and trailing edges of the resulting output amplitude envelope must be expected to contain transient distortion This is why the meter does not open at the beginning of the oscillator on time It ignores the leading edge transients Also the meter must close before the oscillator turns off in order to ignore the trailing edge transients Calculating the times required starts with understanding where the nearest reflecting boundaries are in relation to the loudspeaker source and the measure ment microphone LMS 4 1 User Manual Chapter 6 Analyzer Menu Note The lowest frequency that can be measured will be determined by the largest meter on time that can be tolerated before reflections are included Total Time 10 Ft 8 8mS E 5 Ft 4 4mS 0044S 5 Ft 4 4mS 0044S Closest Reflection The layout shown here depicts a typical situation Here a single reflecting boundary is shown as the limiting factor In order to find out what the maximum meter On time 1s that can be used it will be assumed that 2596 of the meter on time will be used as a dead time safety margin for hold off delay The following time equations are now given for the maximum time window Treflectionz Total boundary reflection path time Bo
311. velopment Selection Menu ilj BRun Sweep Test Sweeps 2 Print Graph 3 Level Curve 4 Compare Curves 5 Name Curve 6 Ratio 15 16 18 71 Delta 15 16 15 8 Graph Display 9 Exit Program Command Lin Enter Menu Selection Number 1 3 Parameter oe Sn LMS 4 1 2 5 User Manual Macro Programs Chapter 13 2 6 LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications 100 95 90 85 80 75 SPL vs Freq SPL Applications 14 60 90 120 150 180 40K 277 SPL Applications Chapter 14 278 LMS 4 1 User Manual Chapter 14 LMS 4 1 User Manual SPL Applications 14 1 Measuring Methods for SPL The process of setting up LMS to measure SPL is trivial when compared to the considerations for the environment Measuring the device or transducer system initially may appear very easy but in reality keeping the environmental effects out of the measurement is by far the most difficult problem to overcome The typical goal of an SPL measurement is to measure the transducer or system without measuring the environment To achieve this goal several methods of SPL measurement have evolved With modern computer assisted analyzers like LMS many more tools have become available to solve this problem To measure SPL without environmenta
312. w shows a graph transferred to the Clipboard as seen in the Clipboard Viewer B ClipBook Viewer Clipboard aH File Edit Security View Window Help e freed SPL vs Freq SHE HHH EEE EHH tH Rent 80 n 100 800 Tale g 8 P257 GP ATI Parking Lot 1111502 Zao at amp AF Tanp ooo ooo o o Ga Ted dde Par 5 4 0 0 22 1 Parion Project Jul 3 2000 Ee Fila 3wasapl db 4 k Clipboard 2 174 LMS 4 1 User Manual Chapter 8 LMS 4 1 User Manual Utilities Menu 8 5 Curve Capture Import Curve Data File Export Curve Data File Export Graphics to File Export Graphics to Clipboard Curve Capture The Utilities Curve Capture menu item will open a eae dialog which will capture a data curve from a raster image file The tool button as shown above on the Utilities toolbar can also be used to activate this item Macro Editor MOF Editar It sometimes happens that one has a printed graph orimage file that contains curve data you would like to use in the program Printed graphs can be transferred to file form by use of ascanner This dialog provides the capability to distill vector curve data directly from a raster image In order to perform this operation three basic requirements must be met The image file must be a BMP format The curve s in the image
313. warranty gives you specific legal rights which may vary from state to state Some states do not allow the limitation or exclusion of liability for consequential damages so the above limitation may not apply to you In addition to the foregoing you should recognize that all complex software systems and their documentation contain errors and omissions LinearX its distributors and dealers shall not be responsible under any circumstances for providing information on or corrections to errors and omissions discovered at any time in the product whether or not they are aware of the errors or omissions LinearX does not recommend the use of this product in applications in which errors or omissions could result in loss of life injury or other significant loss This license agreement shall be governed by the laws of the state of Oregon and shall inure to the benefit of LinearX its successors administrators heirs and assigns or third party licensors United States Federal Government Restrictions If this software is acquired by or on behalf of the U S Federal government or its agencies this provision applies Use duplication or disclosure of this software is subject to restrictions set forth in the appropriate FAR 52 227 19 and DFAR 252 227 7013 documents as applicable The software is commercial computer software and is licensed only with Restricted Rights Other Federal restrictions may also apply LinearX Systems Inc 9500 SW Tualatin Sherwo
314. y 448 13 Hz Gatin Of Frequency Hz C Dn Meter Filter Filter Function Fiat Track Ratio 1 000 448 813 Frequency Hz Data Curve Graph Name 1 My New Curve Freq SPL Phase Lo Freq Hz HiFreq Hz Points Directio 10 000 40000 400 E Dn C Up Contra TTL Pulse Gate Time Calculator 40 Gate Timin Ose Off 20 0000m 20 0000 Ose On MeterDly 5 0000m Sec 10 0000 Meter On Note Static measurements and read ings are obtained by this dialog on a continual basis whenever this dialog is visible Note You can change the color of the meter readouts by clicking on the Value or Freq black readouts LMS 4 1 User Manual Chapter 3 XLR TEST Getting Started 3 4 An Impedance Measurement Taking impedance measurements with LMS is very easy The LMS card has a built in 500 ohm output impedance which is connected directly to the speaker The software then automatically solves this voltage divider and determines the true impedance of the load in ohms In order to make a simple impedance loudspeaker measurement with the LMS analyzer you will need the following A loudspeaker to measure The LMS installation completed An adapter cable with alligator clips to connect to the speaker Since impedance measurements are made by directly connecting the loud pol CLIPS speaker to the oscillat
315. y of this minimum phase transform an analytic filter function was processed and compared to the known data The magnitude phase and group delay graphs below show the original analytic response in Black and the minimum phase transformed response in Blue The generated phase and group delay closely match those of the true analytic response Magnitude Response 120 LMS 4 1 User Manual Chapter 7 Processing Unary Math Operations Binary Math Operations Minimum Phase Transterm Delay Phase Transform Group Delay Transform In Fast Fourier Transform Fast Faurier Transform Speaker Parameters Tail Correction Data Transfer Data Splice Data Healign Curve Averaging Curve Compare Processing Menu 7 4 Delay Phase Transform P E ES ES ES MR DAB Ae ENT The Processing Delay Phase Transform menu item will open a dialog which provides a method of generating phase response data from group delay data The tool button as shown above on the Processing toolbar can also be used to activate this item The delay phase transform can be very useful when you do not already have a matching phase function for your magnitude data and wish to generate the phase based on known or a desired group delay response This situation often occurs when you are creating an arbitrary group delay curve using the Curve Editor and wish to construct a corresponding phase function This transform can also be used to create tran
316. y range These routines extrapolate the response based on the slopes found at the ends of the measured frequency range Since practical measurements often have large variations in the response at the frequency extremes Tail Correction provides the means to reliably fix the tails of the response with a known asymptotic slope xl The library curve list box provides selection of the library curve for the operation This special list box shows the type of data contained in each curve Any curve which is currently being displayed on the graph is denoted by Red vertical lines between the zones of each curve entry Freq SPL Phase 24 0000 24 0000 When the curve entry 15 selected the four numeric fields updated The initial frequency values will be set at 5096 above and below the lowest and highest points in the curve The magnitude slopes of the curve are also measured and their values presented in the other two fields Once you have selected your curve entry and the initial values have been calculated you can then edit these values as desired Since the curve s data will be altered you may wish to make a copy of the curve before performing this operation This will prevent loosing your original data curve should you wish to run the operation again on the original data 145 Processing Menu Chapter 7 An example of Tail Correction is shown below The two frequency thresholds used here were 15Hz and 7kHz The slopes were se
317. y to place the model simulation curve After clicking the Estimate Optimize Simulate button an estimate of the param eters are derived from the input data and then optimized for best fit The simulation curve is then placed into the specified library curve entry The following page shows an example of a typical parameter set generated for the LEAP model The input curve is shown in Blue and the model simulation is shown in Red The resulting parameters are Revc 3 12 Ohms Fo 37 8 Hz Krm 4 58 mOhm Kxm 10 7 mOhm Erm 0 700 Exm 0 689 Qms 3 78 Qes 0 40 Qts 0 36 The simulation curve shows a close match to the original data This result is fairly typical for most loudspeakers However some loudspeakers can have a much more complex electromagnetic system and cannot be represented to this degree of accuracy by the available parameters 135 Chapter 7 Phase Phase Freq 3l req mp 3 12 x 5 S pkr odel 15 FA Reve 1 15 FA Reve Impedance vs Fre Site 1 4 ee 1 11 pr uil Lr ACH m bis _ C e r e E C r r e tT n r e uo r e

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