System 824
Contents
1. System 824 User Manual 7 7 99 Press the View key to return to the View Autostore sub menu View Autostore Press the El left arrow key to back out to the main View Autostore menu showing Autostore ByTime and RT 60 menu items View Autos tore Use the W down arrow key to highlight the ByTime menu item and press the right arrow key to access the ByTime menu and displays The following View ByTime menu appears View BuT ime View BuTime ct Se I Press the Y check key to view the ByTime spectrums recorded during the Autostore 7 7199 Display Views and Menus 2 9 Autostore ByTime Spectral History The Autostore ByTime spectral history has two displays for both ways to view the time history data The first is called the ByTime Spectrum and the second is called the ByTime Graph Spectrum The Autostore ByTime Spectrum display shows just one sample in time and the entire frequency spectrum with fre quency on the horizontal axis Autostore record number rA Display label BT Spectrum Current ByTime sample number pa afr n Filter level in dB gt Ihde in H Total number of ByTime samples din Selected filter frequency 160AHZz ByTime sample time 5 9700 The ByTime display shows that 600 spectra were taken and we are cur rently looking at record number 597 To move to the ByTime Graph dis play press2. Adjust Graph E Scale B Fointz er ar v Exit Press the up and W down arrow keys to adjust the horizontal scale factor Press the Y check key to exit Display Views and Menus 2 13 RT 60 2 14 The RT 60 display is accessed by pressing the View key and highlighting Autostore The menu appears like this Press the D right arrow key to bring up the View Autostore display view menu View Autostore Highlight RT 60 and press the Y check key RT60 The RT 60 analysis display uses the ByTime history to cal culate a room decay time This time is calculated from the cursor position to a point a number of dB down as set by the RT60 dB Down setting and then extrapolated to a drop of 60 dB using a Least Squares slope calculation method RT 60 time in seconds at frequency shown 00 Ba Display label gt RTB 46 1667 s a Current ByTime sample number 3 9e 15 351 j DELTAS RT 60 dB down setting _____ RT 60 delta time US CN 18 Horizontal graph scaling m xi Selected filter frequency 1z58Hz ByTime sample time s 1 104 Total number of ByTime samples System 824 User Manual 7 7 99 The up and W down arrow An auto find routine will automatically locate the cursor to keys move you to the next higher and be 5 dB below the maximum level The auto find is exe lower filter frequency The q left cuted on
3. bytime sample Setup Use the down arrow key to move The Trigger Setup display shows the trigger settings in an to the Setup display or press the interpretive way Only applicable settings are displayed Gei VIEW key highlight Setup and press the D I Check key Shows that triggering is turned on Display Label gt a isger gm ep BB E iti p rm D Arm conditions for 1 8888 seconds Trigger condtions Trig 1688 i 56 for e DD seconds End conditions pe End luam z H for 7 8868 seconds Repeat measurement 2 times Repeat 2 Lines 7 7199 Display Views and Menus 2 5 Autostore Views The interpretation of the Trigger Setup display is as follows The 824 will arm when the 1 kHz filter is greater than 80 0 dB for a period of 1 second e When the level of the 1 kHz filter drops below 80 0 dB for 0 seconds immediately the 824 is triggered and begins taking a measurement The measurement continues until the End condition is met which means that the level must drop below 50 dB for 2 seconds The measurement will repeat 2 more times before stop ping As the settings are changed the Trigger Setup display will show the relevent settings in an easy to read form If triggering is enabled the record is stored when the End conditon is met or when the MH R S key stops the measurement If triggering is not enabled the record is stored when the CD R S key st
4. On board RT60 analysis Room Criterion Acoustic Impulse Event Analysis Pass by Event analysis The 824 RTA option provides the following features RTA for fast spectral data Performs room acoustics RT60 RC NCB HTL Averages any number of spectra Uses measurement triggering for flexible acquisition Autostores up to 400 spectra per second Has both exponential and linear detectors Introduction to 824 RTA Setup Menu This 824 RTA Addendum assumes that you are familiar with the opera tion of the 824 For general opera tion see the 824 Reference Manual 1824 01 Rev B Settings Menu This manual has 2 chapters and covers the following topics Chapter I Introduction to 824 RTA Setup Menu Dis cusses the features and applications for the RTA Option Explains the Setup Menu Chapter 2 Display Views and Menus Explanation of the different views available showing RTA Spectra Trig ger Status Autostore Records and Spatial Averaging For other information pertaining to the RTA Instrument see the following in the 824 Reference Manual For Data Storage see Chapter 4 For Printing RTA Reports see Chapter 8 For I O commands see Appendix C For RTA specifications see Appendix D The Settings menu for the RTA instrument is accessed from the SETUP key There are three permanent RTA instru ment definitions ID available ROOMS RTA RT60 A RTA and RT60 B RTA To select an RTA instrument press th
5. Ref erence manual on creating your own instrument IDs RT60 A The RT60 A setup is designed to gather data to measure an RT60 by stimulating a room with a steady state noise It is configured in the following way Detector Linear Detector Time 0 01 seconds Autostore Yes e PreTrigger 50 Save ByTime Yes Triggering ON Trigger Source 1 kHz Arm Mode L 7 Arm Level 80 0 dB Arm Time 2 0 second Trigger Mode L Trigger Level 80 0 dB Trigger Time 00 0000 seconds End Mode Time End Time 3 0 seconds Then Stop RT60 B The RT60 B setup is designed to measure an RT60 by stimu lating a room with impulsive noise such as a gunshot or a ballon popping and is configured in the following way Detector Linear System 824 User Manual 7 7 99 Rooms RTA Instrument Definition Detector Time 0 01 seconds Autostore Yes PreTrigger 10 Save ByTime Yes Triggering ON Trigger Source 1 kHz Arm Mode Now Trigger Mode L gt Trigger Level 80 0 dB Trigger Time 00 0000 seconds End Mode Time End Time 3 0 seconds Then Stop The System 824 has an Instrument Definition that makes it easy to measure room criteria NCB and RC using the RTA in 1 1 octave bandwidth The setup is configured to take data for 10 seconds at each location in a room Each measure ment is automatically stored in the Autostore ByTime his tory ROOMS RTA is configured in the following way
6. in dB 33 3 m Bandwidth 1 1 or 1 3 oct gt gE BUT SERT Selected filter frequency gt 1ammuHz Ge mre Live spectrum s duration n unsn 1 1 octave cursor AME d Leq Press the fei View key again to dis The LEQ display shows the equivalent level of all the sam play the View RTA menu Press ples A current or overall reset will reset the Leq the up and W down arrow keys to highlight the desired display and press the Q check key to select the highlighted display 2 2 Display label RTA Le a Filter level in dB _ _ gt 5 7 E ER i oe Bandwidth 1 1 or 1 3 oct t d n Selected filter frequency 1manHz Leq spectrum s duration J 04 43 54 1 1 octave cursor NOTE Leq Max and Min are measured only while triggered if trig gering is enabled If triggering is disabled they are measured while the 824 is running by pressing the D R S key If Autostore is enabled Leq Max and Min will be reset at every trigger or run if Triggering is off otherwise they will accumulate for each R S mea surement until manually reset System 824 User Manual 7 7 99 There is no correlation between the RTA Max spectrum which are the bin by bin maximum values for each fil ter and the instantaneous maximum spectrum when the broadband Lmax occurred This
7. is for repair or replacement of the non conforming product or part thereof or refund of the purchase price bur in no event shall LarsoneDavis its contractors and suppliers of any special indirect incidental or consequential damages whether the claims are based in contract in tort including negligence or otherwise with respect to or arising out of the product furnished hereunder Representation and warranties made by any person including its authorized dealers representatives and employees of LarsoneDavis which alter or are in addition to the terms of this warranty shall not be binding upon Larson Davis unless in writing and signed by on of its officers Disclaimer The following paragraph does not apply in any state or country where such statements are not agreeable with local law Even though LarsoneDavis has reviewed its documentation Larsone Davis provides this publication as is without warranty of any kind express or implied including but not limited to the implied warranties of merchantability or fitness for a particular purpose This documentation is subject to change without notice and should not be construed as a commitment or representation by Larson Davis 824 RTA USER MANUAL This publication may contain inaccuracies or typographical errors LarsoneDavis will periodically update the material for inclusion in new editions Changes and improve ments to the products and or programs described in this manual may be ma
8. setting is set to Repeat 0 255 Average Count This is the number of times the measurement is repeated and averaged when the End Then setting is set to Average 0 9 Trigger Settings Menu continued Run on Input When set to Yes the instrument will run when the logic input line changes to the Run Logic In state No Yes Run Logic In Low High 7 7 99 Introduction to 824 RTA Setup Menu 1 13 These lines can be used to control lights in a remote control device to indicate the current state Logic Out The Logic Out bit value determines which lines heater cal or logic will be used on the control connecter to indicate each of the five states 0 65535 The setting for the Output Logic state selection is combined into one 15 bit setting that has 3 bits one for each output line Logic Out Heater Out and Cal Out for each ofthe five states Stop Ready Armed Triggered Ended Use the table below to determine how these will be set up Ended Triggered Armed Ready Stop 16284 8192 4096 2048 1024 512 256 128 64 32 16 8 4 2 1 Logic Logic Logic Logic Heat Cal Cal Heat Cal Out Heat Cal Out Heat Cal Out The default setting indicates the following Ended state is output on logic out Triggered state is output on logic Out Armed state is output on cal Ready state is output on heat Stop state is not outputed The default sett
9. 0 400 samples Save ByTime This feature allows the user to enable or disable turn storage of ByTime data in an autostore record With this feature turned off and the Autostore function turned on the 824 will only store Leq Max and Min spectra Introduction to 824 RTA Setup Menu 1 7 You can also set the trigger source from the Trigger Status display by moving the cursor to the desired band press the Q check key and select Set Source from the menu Triggering Turns triggering on or off There are four parts to triggering Arm Trigger End and Then Arm and Trigger work in tandem to create a two step trigger to start an Autostore End and Then work together to determine when to stop measur ing Trigger Source Allows the user to select a filter or flat overall as a trigger source Arm Settings Menu Elapsed time and qualifying times are evaluated only when a new ByTime sample is created This causes the minimum effective time resolution to become the same as the update interval L indicates the level of the filter specified by the Trigger Source set ting Arm Mode The 824 becomes armed when the following conditions are met Now The 824 will arm immediately L lt When the level is less than the Arm Level for the Arm Time then the 824 will arm e L When the level is equal to the Arm Level 0 5 dB for Arm Time then the 824 will arm e L gt When the level is greater tha
10. 4 starts recording an Autostore record This is also a qualifier for the level settings If the System 824 User Manual 7 7 99 End Settings Menu 7 7 99 time is non zero then the level condition must be met for the specified time before the trigger will occur 00 0000 to 99 9975 seconds Trig Samples When the Trigger Mode is set to Count Trig Samples is the number of samples that will be taken before the 824 starts recording an Autostore record 0 65535 Trig Logic In When the Trigger Mode is set to Input the 824 starts recording an Autostore record when the logic input line changes to the Trig Logic In state Low High End Mode The measurement ends when the following conditions are met Never The measurement continues until the run stop key is pressed e L lt When the level is less than the End Level for End Time then the 824 stops recording an Autostore e L When the level is equal to the End Level 0 5 dB then the 824 stops recording an Autostore L gt When the level is greater than the End Level for End Time then the 824 stops recording an Autostore Input The 824 stops recording an Autostore after the logic input line changes to End Logic In state Introduction to 824 RTA Setup Menu 1 11 If set to 0 seconds at least 2 samples will be stored One due to the Arm Sample and one due to the Trigger Sample If set to 0 s
11. 7 7 99 Introduction to 824 RTA Setup Menu Bandwidth 1 1 octave Detector Linear Linear Detector Time 00 1000 seconds Autostore Yes ByTime No Triggering ON Trigger Mode Now End Mode Time End Time 10 0000 seconds End Then Stop System 824 User Manual 7 7 99 RTA Views Use the up and D I down arrow keys to highlight the desired display 7 7 99 Display Views and Menus This Chapter explains the various displays available under the View key Once a measurement has been taken the 824 allows you to view the results and manipulate the data The RTA Display Views are accessed through the e View key To select the RTA Display Views press the e View key The following menu will appear Now press the D right arrow key to bring up the View RTA display view menu The RTA display view menu offers 5 choices Live Leq Max Min and Times Use the QD check key to select the Live display Display Views and Menus 2 1 Live If the sample time is greater than The RTA Live display shows the live spectrum and is the cur 0 25 seconds a display spectrum is rent sampled data with a sample time based upon the detector generated and displayed to keep the detector time and detector store rate settings The Live display live data current is updated regularly when the 824 is running Display label 9 RTA Live el 100 see eee ee Current filter level
12. amples the measurement will not end Then Settings Menu 1 12 Time The 824 stops recording an Autostore after End Time Count The 824 stops recording an Autostore after End Samples of data have been received End Level This level is used when the End Mode is set to Level L lt L L gt It is the amplitude in dB at which the 824 will stop recording an Autostore record 0 0 255 9 dB End Time The 824 stops recording an Autostore record when the End Time has been satisfied e 00 0000 to 99 9975 seconds End Samples The 824 stops recording an Autostore after End Samples has been satisfied 0 65535 End Logic In When the End Mode is set to Input the 824 stops record ing an Autostore record when the logic In line changes to End Logic In state Low High End Then After the measurement ends the 824 may do the following System 824 User Manual 7 7 99 Repeat Averaging requires the End Mode to be set to Time or Count so that all records are the same length Stop The measurement ends Repeat The measurement repeats when the Arm and Trigger settings have been satisfied A new Autostore record is created for each repeated measurement Average The measurement repeats like repeat above except that the spectra are averaged with the preceding Spectra Repeat Count Allows the user to select how many times the measurement will repeat when the End Then
13. d filter Ff amp Selected filter frequency LO dis adn E HTL 40 HTL status _ Fail The NTL status indicator can show the following Display Views and Menus 2 21 Pass indicates the recording environment is suitable to produce recordings without audible background noise e Fail indicates the recording environment is NOT suit able to produce recordings without audible background noise 2 22 System 824 User Manual 7 7 99 Index A Arm Level aono 1 9 Arm Logic In ausi otros 1 9 Arm Mode 1 8 Arm Samples 1 9 Arm Settings Menu 1 8 Arm Time uio ooo 1 9 Autostore E 1 7 Autostore ByTime Graph 2 10 ByTime Spectral History 2 10 ByTime Spectrum 2 10 Autostore Leq ssssssiissseeeseeee 2 7 Autostore Max e 2 8 Autostore Settings Menu 1 7 Autostore Views 2 6 Average Count 1 13 Average History 2 18 Average History Check Menu 2 19 B Bandwidth Setting 1 5 BY MMe oie eibi 1 7 2 10 ByTime Graph Check Menu 2 12 ByTime Spectrum Check Menu 2 11 D Detector Setting 1 5 3 26 99 E E d Leye arnser 1 12 End Logic EEN 1 12 End Mode 1 11 End Samples eom 1 12 End Settings Menu 1 11 End Then EE 1 12 End Time idein 1 12 Exponential Detector Time 1 6 Exponentia
14. de at any time 824 Serial 824 RTA USER MANUAL Table of Contents Chapter 1 Settings MOT escort oa Epid eine n R Settings DesertpHOHSs cdd dtu cmd tomes dri dua Me RTA Settings Mets e totes anu reed cd Autostore Settings Ment ics vecccctev sinus o did teo nae eebe Arm Settings MICH d den aon e iie ed Trigger Settings Merlin ciet open tec ie ete er eiut os Etringer f ecd Then Settings Menu suco oet iere E enu epn eei Trigger Settings Menu continued sssssssss RTA Settings continued tee ettet dass RT60 A and RT60 B Instrument Definition Rooms RTA Instrument Definition sess Chapter 2 REA VIEWS s TG OST Ies cut aea ptio A ee PRU STORE E Autostore ByTime Spectral Historie ByTime Spectrum Check Men ByTime Graph Check Menu tenet tete REGO Sie cei tur do Mt bog d nee n Laden bou ito att ened RTO Cheek Ment irridet tet c eR bui Rare brad x ege Spatial Avg EE Spatial Avg Check Menu sseseeenerenen Avg History Cheek Menu sio rea ES ROOMS VIEWS qusc etur dee De tU tup DEUM ba Peden pu rv epu ed 3 26 99 System 824 user manual 3 26 99 7 7 99 Introduction to 824 RTA Setup Menu Welcome to the System 824 Real Time Analysis Firmware Option This option adds high speed spectral data gathering to the System 824 and will enable you to perform the follow ing measurements Architectural Acoustics
15. demand from the check menu and the first time the and right arrow keys move you _RT 60 display is selected There is a vertical line for the cur to the previous and next ByTime sor specifying the beginning of the measurement and a hori sample zontal line drawn at the dB down level Auto find also sets the horizontal zoom so that the whole decay fits on screen RT60 Check Menu Pressing the Y check key when viewing the RT60 display puts you in the RT60 check menu The check menu is shown below The check menu offers the following options RT60dB Down dB down setting for RT 60 calculation e Auto Select Auto Select cursor position e Graph V See page 2 13 for explanation e Graph H See page 2 13 for explanation View Back Returns you to the previous display 7 7 99 Display Views and Menus 2 15 Spatial Avg Views 2 16 The Spatial Averaging facilities allow user selected spectra to be averaged on an equal weighting basis It is often used to average the spectra that were measured at various loca tions around a noise source or across the length of a wall or partition The resulting average is displayed and can be stored into a history for later viewing The Spatial Avg Display Views are accessed through the e View key To select the the Spatial Avg Display Views press the View key and highlight Spatial Avg The following menu will appear RTA Trigger Autostore Spatial Avan Now press the D rig
16. e SETUP key scroll down to RTA and press the Y check key The RTA Live view will now be displayed Press the SETUP key again to return to the SETUP menu At the top of the Setup menu Edit Settings will be highlighted Press the Y check key to edit the RTA settings menu See chapter 5 of the 824 Reference Manual for more details on selecting instrument IDs System 824 User Manual 7 7 99 7 7 99 The menu layout of the RTA settings is shown in the table below Menu Items Title RTA Submenu Gain dB Available Settings Options User customized text entry 20 10 0 10 20 30 40 50 Available Settings Options Bandwidth 1 1 1 3 Detector Lin Exp Lin Detc Time Exp Detc Time seconds 0 0025 to 99 9975 sec 1 32 1 16 1 8 1 4 1 2 Exp Store Rate 1 2 second 1 8 second Transducer Condnsr Elctret Direct Autostore Autostore No Yes Pretrigger 0 400 samples Save ByTime No Yes Trigger Setup Triggering No Yes Trigger Source Any 1 1 or 1 3 octave filter Flat Introduction to 824 RTA Setup Menu 1 3 Menu Items Trigger Setup continued Submenu Available Settings Options Available Settings Options Now L lt Arm Mode L gt Input Time Count Arm Arm Level 0 0 255 9 dB Arm Time 00 0000 to 99 9975 sec Arm Samples 0 65535
17. e Settings Menu When a linear detector is selected the store rate is that of the linear detector When an exponential detector is selected samples are stored every exponential detector time multi plied by the exponential store rate Pretrigger samples are only avail able when the trigger function is used to start the measurement When Autostore is turned on ByTime records are automatically stored By default the RT60 A and RT60 B instruments have Autostore and ByTime enabled 7 7 99 Autostore Turns the Autostore function on or off It allows the 824 to measure and store basic information such as the Leq Max and Min spectra when a measurement is ended by the trig gering setup or by pushing the run stop key When Autostore is on ByTime data is automatically stored in the Autostore record if Save ByTime is set to Yes For setups with a linear detector spectra are stored once every linear detector time For setups with an exponential detector samples are stored every 1 256 of a second to 32 seconds Pretrigger Allows the user to select the number of pretrigger samples that are stored with an Autostore record The 824 keeps a circular buffer of the most recent 400 samples The buffer is reset every time a new run is started The number of spectra in the buffer is displayed in the Trigger Status view This set ting determines how many of these spectra to copy into the beginning of the Autostore record
18. e spectrum display puts you in the check menu The check menu is shown below HuTime HuTime GraphLD Autostore a Locate tAVerage o Rooms LI The check menu offers the following options ByTime Graph View the time graph of one filter e Autostore View the Autostore Leq Max and Min spec tra 7 7 99 Display Views and Menus 2 11 The Locate menu helps you find the record you would like to view The Find function allows you to enter the exact record number that you would like to view The Spatial Averaging displays and menus are covered later in this chap ter If 1 3 octave filters are selected the Rooms display gives you the Hearing Threshold Level or HTL for this spectrum ByTime Graph Check Menu 2 12 Locate Locate an Autostore ByTime record Next The next Autostore record Prev The previous Autostore record First The first ByTime record Last The last ByTime record Find Finds the specified ByTime record Average Add spectrum to spatial average or view spa tial spectra average Rooms View NCB and RC Room Criteria for this spec trum must be in 1 1 octave filters Graph Adjusts the graph scale and offset See 824 Ref erence Manual Graph Level Allows numerical entry of graph level in dB Graph Scale Allows numerical entry of graph scale Pressing the Y check key once when viewing the ByTime spectrum display puts you in the check men
19. filter frequency 636 E Autostore duration Be Number of autostore records To move to the next Autostore display press the Y check key and then the D right arrow key 7 7 99 Display Views and Menus 2 7 Max The Autostore Max display shows the maximum level obtained by each filter and the broadband maximum level from all the Autostore ByTime records in a particular mea surement Autostore occurance date and time Hax Dana 16 54 40 a Display label Record number total records Store Filter level in dB 29 Selected filter Stee 53 Autostore duration p Number of autostore records Min The Autostore Min display shows the minimum level obtained by each filter and the broadband minimum level from all the Autostore ByTime records in a particular mea surement Autostore occurance date and time a Display label p Him DUn01875 16 54 40 Py Record number EES a Filter level in dB 2 3 S Bandwidth 1 1 or 1 3 octave 9M99 dl Selected filter frequency B Autostore duration Number of autostore records Pressing the Y check key twice while in any of these dis play views will toggle you between the Leq Max and Min autostore displays The up and W down arrow keys will move you to the next or previous Autostore records
20. ht arrow key to bring up the View Avg display view menu S Spatial Avg The View Avg display view menu offers 2 choices Spatial Avg and Avg History Use the Y check key to select the Spatial Avg display Spatial Avg The Spatial Avg display shows the spectra which have been currently averaged System 824 User Manual 7 7 99 Display label Spatial Avg E 12D EOE CE iun wert n mn RRE Bandwidth 1 1 or 1 3 oct gt dBi Bursa teo deeg Selected filter frequency sapHs EIE luet Spatial averaged sample count _ gt Annunciator or note Test 2 Spatial averaged spectrum un Ege Any display which shows a spectrum can be averaged using the Aver age item on its check menu There is effectively no limit on the number of spectra that may be aver aged Spatial Avg Check Menu 7 7 99 NOTE If the right digit of the annunciator is numeric then it will auto increment with each spatial average store operation from the check menu Each display that can show a spectrum has a check menu item Average that when selected will prompt the user Add to Average It then offers the following choices Yes averages the spectrum being viewed to those previ ously averaged No the spectrum is not averaged into the previous aver age but the spatial average display is shown Cancel nothing happens and the previous d
21. i Low Arm Logic In High Now L lt L Trigger Mode L gt Input Time Count Trigger Trigger Level 0 0 255 9 dB Trigger Time 00 0000 to 99 9975 sec Trig Samples 0 65535 i Low Trig Logic In High Never L lt L End mode L gt Input Time Count End End Level 0 0 255 9dB End Time 00 0000 to 99 9975 sec End Samples 0 65535 t Low End Logic In High Stop End Then Repeat Average Then Repeat Count 0 255 Average Count 0 9 Run on Input No Yes System 824 User Manual 7 7 99 Settings Descriptions ee Submenu Available Settings Options Available Settings Options Trigger Setup 4 continued Logic Out 0 65535 5 10 RT60 dB Down 50 30 Note 8 Characters RTA Settings Menu 7 7 99 Title Setting Use the title setting to create a title or heading for printed reports This title will be placed at the top of each RTA report you print Gain Setting Gain adjusts the voltage level delivered to the measuring portion of the meter from the microphone and preamplifier Bandwidth Setting Selects 1 1 or 1 3 octave filter bandwidth for real time anal ysis Detector Setting Selects the averaging method to be used Linear Exponential Introduction to 824 RTA Setup Menu 1 5 The Linear Detector Time will be adjusted to an integer multiple of 0 0025 seconds 2 5mS The Exponential Detector Time muti plied by the Exponential Store Rate gives the to
22. ing is 04768 which is shown by the bolded squares in the table above The Logic output is on pin 2 of the control connector and will be driven to 5 volts through a 1000 ohm resistor when asserted or zero volts when not asserted Pin 1 is the ground signal System 824 User Manual 7 7 99 RTA Settings continued RT60 dB Down The automatic RT60 algorithm will search for a point 5 dB down from the peak and then calculate an RT60 between that point and the next point RT60 dB Down from the 5 dB point NOTE If RT60 dB Down is set to 30 dB the RT60 will be calcu lated for the data between 3 and 35 dB down from the max 5dB 10dB 20dB 30dB Note An 8 character note field is provided to annotate a spatial average This is useful when describing the measurement you are taking and keeping track of different measurements or their location RT60 A and RT60 B Instrument Definition The System 824 contains two special RTA IDs on the setup menu which will simplify making an RT60 measurement Both of these setups load the RTA instrument but with the triggering arm and end menus configured for two types of measurements The RT60 A and RT60 B RTA instruments are accessed from the SETUP key 7 7 99 Introduction to 824 RTA Setup Menu 1 15 Although the settings are predefined in RT60 A and RT60 B they can be changed at any time and used as cus tomized setups for a personalized RT60 measurement See the 824
23. is a feature of the SSA instrument Max The Max spectrum shows the maximum level obtained by each filter and the maximum broadband Flat level This is a bin by bin maximum level The Max spectrum is reset by a current or overall reset Once in a display view you can sim ply use the up and arrow keys to move between the views Display Label gt E TH Fax el Filter level in dB 1BH4 3 ion Bandwidth 1 1 or 1 3 oct gE su Selected filter frequency 14HBHz m Leq spectrum s duration We 10 1000 1 1 octave cursor EI KI res Min The Min spectrum shows the minimum level obtained by each filter along with the minimum broadband Flat level This is a bin by bin minimum level The Min spectrum is reset by a current or overall reset Display label pa RTA Hin e KI se Filter level in dB 35 7 CT EE Bandwidth 1 1 or 1 3 oct dBl Bee Selected filter frequency 1AAAHZ e Io Leg spectrum s duration M _ 10 1000 He 1 1 octave cursor Display Views and Menus 2 3 Times The Times display shows the date and time when the overall measurement began and the date and time when the last measurement ended These times are not affected by the automatic reset or the manual Current reset but are reset with an OverAll reset The total run
24. is sampled 32 times each second Low High Introduction to 824 RTA Setup Menu 1 9 Trigger Settings Menu L indicates the level of the filter specified by the Trigger Source set ting Trigger Mode The 824 triggers and starts recording an Autostore record when Armed and the following conditions are met Now The 824 starts recording an Autostore immedi ately e L lt When the level is less than the Trigger Level for Trigger Time then the 824 begins recording an Autostore e L When the level is equal to the Trigger Level 0 5 dB for Trigger Time then the 824 begins record ing an Autostore e L gt When the level is greater than the Trigger Level for Trigger Time then the 824 begins recording an Autostore Input The 824 starts recording an Autostore when the logic input line changes to Trigger Logic In state Time The 824 starts recording an Autostore after Trig ger Time seconds Count The 824 starts recording an Autostore after Trig Samples of data have been received Trigger Level This level is used when the Trigger Mode is set to Level L lt L L gt This is the amplitude in dB at which the 824 will start recording an Autostore record It must be valid for the period of time set by Trigger Time 0 0 255 9 dB Trigger Time When the Trigger Mode is set to Time this is the time that must pass before the 82
25. isplay is shown Once one or more spectra have been averaged they can be stored into the Avg History The Spatial Avg check menu is shown below To access the check menu simply press the Q check key when in the Spatial Avg display Spatial Ave Display Views and Menus 2 17 The 824 will prompt you to reset the Spatial Avg buffer This does not reset the Avg History If the data being viewed has come from a stored file the average function is not available and will beep instead of bringing up the prompt Add to Average Number of spectra averaged 9 Spatial average history note field gt Test Total number of spatial average history records The check menu offers the following options Note Note is used to describe this average which is to be stored to the Avg History Store Store Spatial Average in Spatial Average History Reset Resets the Spatial Average buffer Avg History View the Spatial Average History Rooms View Room Criteria for this spectrum e View Back Return to the previous display e Graph Adjusts the vertical graph scale and offset Avg History The Avg History display shows a history of the spatial aver ages which have been stored using the Store function in the Spatial Avg check menu Use the ei View menu or the Spatial Avg check menu to access the Avg History display Occurance date and time Disp
26. l Store Rate 1 6 G Gain Setting ences 1 5 L Linear Detector Time 1 6 Logic Out xseseesuti deseo 1 13 N INGLE 4 treo iatis 1 15 P PretrigGer oos oss 1 7 R Repeat Count 1 13 ROOMS iere te S nuke 1 17 Rooms HTL oe etes 2 21 Rooms NCB iot eer 2 20 Ereegnes es 1 10 Rooms RC 2 20 Trigger Views 2 4 Rooms Views esiste 2 19 WIPO EE 1 8 RT 60 eege tala 2 14 RT60 Check Menu 2 15 RT60 dB Down sssssssesesesssees 1 14 RTDU A iuc Debet 1 15 CO iet rto oe 1 15 RTA seni etnies 2 2 RTA Eves aise eel eames 2 2 RTA Mae utis 2 3 RTA e rera kenan hai 2 3 RTA Settings Menu 1 5 RTA Titles 2e cet 2 4 RTA Views cote etes 2 1 Run Logic Iioc 1 13 Run on Input 1 13 S Save ByTime 1 7 Settings Descriptions 1 5 Settings Menu 1 2 Spatial Average 2 16 Spatial Average Views 2 16 T Then Settings Menu 1 12 Title Setting acs ossis 1 5 Transducer ER 1 6 Trig Logic In EE 1 11 Trig Samples 1 11 Trigger Level iuuenis 1 10 Trigger Mode ums 1 9 Trigger Settings Menu 1 9 Trigger Setup unte ete 2 5 Trigger Source 1 8 Trigger Status eine 2 5 ii system 824 user manual 3 26 99
27. lay Graph Adjusts the vertical graph scale and offset NCB and RC are calculated and dis played from any spectral display including snapshot or Averaged Spectrum and are accessed from their individual check menus 7 7 99 The Rooms Views are accessed from the check menu of every display that can show a spectrum The Rooms displays consist of RC NCB and HTL All these measurements are based on ANSI 12 2 1995 The NCB and RC Criteria for 1 1 octave data calculates the following Display Views and Menus 2 19 SIL speech interference level e Pass Fail on Rumble check e Pass Fail on Hiss check Mid frequency average Lmf and RC Neutral Hiss Rumble or Vibration Rumble check RC NCB and HTL are accessed in the Rooms display from any spectrum s check menu NCB and RC are only displayed Rooms NCB when using 1 1 octave filters The Rooms NCB display shows the noise criterion for the spectrum being displayed when Rooms is chosen from any spectrum check menu Display label ROOMS HCE E Level in dB of selected filter gt 42 zdB ua Selected filter frequency gt imdi jgn Room level in dB SIL Soa CEU 36 8dB i o a Room data W HD e un iud NCB status tH NCB curve line an annoyance or loudness spectrum indication The NCB status indicator can show the following Under indicates that SIL speech inte
28. lay label p MN Sieg Current average history record number Bug xb cii Level in dB of selected filter 38 0 Bandwidth 1 1 or 1 3 oct J9 i BE Selected filter frequency AHAH al EEN S i 40 In order to clear the Avg History records an overall reset is required 2 18 Use the up and W down arrow keys to move to the previous and next spatial average history records To manipulate the Avg History records press the Y check key to access the Avg History check menu System 824 User Manual 7 7 99 Avg History Check Menu If you are viewing an Avg History record use the average function to average records which are already in history together all records are the average Remember that weighted equally If you have an average history record which was comprised of 100 samples it will be averaged as one record Rooms Views The Avg History check menu is shown below The check menu offers the following options Edit Note Edit the note of this stored record Locate Locate a Spatial Avg history record First The first Spatial Avg history record Last The last Spatial Average history record Find Finds the specified Spatial Average his tory record Average Add spectrum to spatial average Rooms View Room Criteria for this spectrum View Back Return to the previous disp
29. n the Arm Level for Arm Time then the 824 will arm Input The 824 arms when the logic input line changes to Arm Logic In state Time The 824 arms after the Arm Time seconds in the ready mode System 824 User Manual 7 7 99 Arm Time is used in conjunction with Arm Level as a qualifier for the level setting See example below A typical trigger having the follow ing settings Trigger Source 1 kHz Arm Level 80 0 dB Arm Mode L gt Arm Time 2 0 second Would transition to arm after the 1 kHz filter level was greater than 80 dB for 2 seconds 7 7 99 Count The 824 arms after Arm Count samples of data have been received Arm Level This trigger level is used when the Arm Mode is set to a level state L lt L L gt This level must be reached before the 824 will arm 0 0 255 9 dB Arm Time When the Arm Mode is set to Time the Arm Time must expire before the 824 will arm This is also a qualifier for the level settings If the time is non zero then the level condition must be met for the speci fied time before Arm Mode is entered e 00 0000 to 99 9975 seconds Arm Samples When the Arm Mode is set to Count Arm Samples is the number of samples that will be taken before the 824 is armed 0 65535 Arm Logic In When the Arm Mode is set to Input the 824 will arm when the state of the Logic In line changes to this level Logic In
30. ning time is also dis played This is the total elapsed time of all measurements since the previous OverAll reset Display label e FTH Times Overall start date and time c c bae 12 41 27 Overall end date and time to HBHBaWan i3959 12 43 44 Overall runtime JM OverAll Run Time B dggz 16 Trigger Views The Trigger Display Views are accessed through the e View key To select the Trigger Display Views press the View key The following menu will appear Use the up and W down arrow keys to highlight Trig ger Now press the D right arrow key to bring up the View Trigger display view menu 2 4 System 824 User Manual 7 7 99 View Trigger The Trigger display view offers 2 choices Status and Setup Use the Y check key to select the Status display Status The Trigger status display shows the current state of the RTA showing either Stopped Ready Armed Triggered or End This display shows a copy of the Live spectrum and its graph Also displayed is the repeat count when set to repeat or repeat with average and the number of samples gathered pre or post trigger Depa E Trigger Status LE Trigger State Stop um LL Filter level in dB er 25 7dB ap Selected filter frequency 39 9 _ SHGHz Trigger source frequency B L 164 M ce CMS mI I No of Dee or triggered 1765 I J
31. ops the measurement If you just came from the Trigger Setup display press the q left arrow key to back out to the main VIEW menu 2 6 An Autostore is a historical record of triggered data that is stored automatically when the Autostore setting is set to Yes The Autostore includes summary data Leq Max and Min spectra covering the entire duration of the Autostore and ByTime spectra RT 60 analysis of the ByTime spectral time history is also provided The Autostore Display Views are accessed through the e VIEW key To select the Autostore Display Views press the Gei VIEW key and the up and W down arrow keys to highlight Autostore The following menu will appear like this System 824 User Manual 7 7 99 Now press the D right arrow key to bring up the View Autostore view menu View Autostore Press the D right arrow key to select the available Autostore summary data views which are Leq Max and Min Use the up and down u arrow keys to highlight the desired vieu tos tore display Press the Y check key to view the Leq display Leq The autostore Leq display shows a bin by bin equivalent level of all the ByTime Autostore samples Autostore occurance date and time M Leg 1904 1999 16 54 40 Display label Astor e p Record number Filter level in dB 199 Bandwidth 1 1 or 1 3 oct _ _ gE Selected
32. oystem 824 RTA Option Reference Manual Larson Davis 1681 West 820 North Provo UT 84601 1341 Phone 801 375 0177 FAX 801 375 0182 www lardav com 1824 04 Rev A 824 RTA USER MANUAL Copyright Copyright 1999 by Larsone Davis This manual and the software described in it are copyrighted with all rights reserved The manual may not be copied in whole or in part for any use without prior written consent of Larson Davis Warranty LarsoneDavis warrants this product to be free from defects in material and workmanship for two years from the date of original purchase During the first year of warranty period LarsoneDavis will repair or at its option replace any defective component s without charge for parts or labor if the unit is returned freight prepaid to an authorized service center The product will be returned freight pre paid During the second year warranty period there will be no charge for replacement parts provided the product is returned to LarsoneDavis repair facility Product defects caused by misuse accidents or user modification are not covered by this warranty The warranties described above are exclusive and in lieu of all other warranties whether statutory express or implied including but not limited to any implied warranty of merchantability or fitness for a particular purpose and all warranties arising from the course of dealing of usage or trade The buyer s sole and exclusive remedy
33. rference level is under the defined range for NCB Over indicates that SIL is above the defined range for NCB OH indicates the NCB Hiss check failed R indicates the NCB Rumble check failed Rooms RC Use the up and D I down arrow The Rooms RC display shows the noise criterion for the keys to move between the RC and spectrum being displayed when Rooms is chosen from a NCB displays check menu 2 20 System 824 User Manual 7 7 99 Display label ROOMS FC Level in dB of selected filter 42 BB Aan Selected filter frequency PARERES OOOH mm Boom midfrequency average level Lf 58 SdB T EE Room data Bm RC An H RC status CRU RCB line fixed slope annoyance or interference indication line The RC status indicator can show the following Under indicates that Lmf midfrequency average level is under the defined range for RC e Over indicates that Lmf is above the defined range for RC N indicates the RC is Neutral RV indicates the RC Vibration Rumble check failed R indicates the RC Rumble check failed Rooms HTL The Rooms HTL display is only The Rooms HTL display shows the Hearing Threshold available when 1 3 octave filters are Level for the spectrum being displayed when Rooms is selected 7 7 99 chosen from any spectrum s check menu Display label m FOOHS HTL m Level in Ap of selecte
34. tal Auto Store time When a condenser microphone is used the 824 requires a stablization time of approximately 45 seconds before a measurement can be taken Linear Detector Time Allows the user to select the averaging time when the linear detector is used Also sets the storage rate for the Autostore ByTime records 0 0025 to 99 9975 seconds Exponential Detector Time When an exponential detector is selected this parameter sets the exponential decay time 1 32 to 64 seconds Exponential Store Rate Selects the rate at which spectral samples are output and stored when the detector is exponential The interval time time between successive samples is equal to the exponential detector time multiplied by the exponential store rate e 1 2 1 8 NOTE For example if the detector time is 1 8 and the store rate is 1 2 then the 824 would generate spectra samples at a rate of 16 times per second Transducer Condenser This indicates that the microphone being used is an air condenser type and the 824 will generate the appropriate polarization voltage Electret This indicates that the microphone being used is an Electret pre polarized microphone The 824 will not generate any polarization voltage Direct This indicates that no microphone is being used and electrical signals are being injected directly into the preamplifier No polarization voltage is generated System 824 User Manual 7 7 99 Autostor
35. the Q check key twice 2 10 With the up and amp down arrow keys you can view each ByTime spectrum sample that was recorded Use the Q left and D right arrows to move the cursor to look at each individual frequency NOTE Notice as you move through each ByTime sample that the sample time changes A minus sign in front of the time indicates that they are pretrigger samples 0 is the time where the trigger occured System 824 User Manual 7 7 99 Graph The Autostore ByTime Graph display is a time graph of just one filter frequency plotted with time as the horizontal axis This graph is useful in seeing the level rise or fall charac teristics of each individual filter Autostore record number Display label Curent ByTime sample number EP X raph Filter level in dB fe v E Total E of jBytime samples dpi Horizontal prani scaling p gt Selected filter frequency 9 STI ByTime sample time 9 5 4700 The up and W down arrow keys move you through each filter The d left and D right arrow keys move to the previous and next ByTime sample ByTime Spectrum Check Menu As discussed earlier in order to move between the ByTime spectrum display and the ByTime Graph display you pressed the Y check key twice toggling between the ByTime Spec trum view and the ByTime Graph view Pressing the V check key once when viewing the ByTim
36. u The check menu is shown below The check menu gives you the following options ByTime Spctrm View the Bytime spectrum System 824 User Manual 7 7 99 The Locate menu helps you find the record you would like to view The horizontal graph adjustment Graph H provides a useful feature that allows you to view a large amount of time data in the ByTime Graph view A scale factor of 1 to 1024 can be selected A scale factor of greater then 1 will cause multiple pieces of time data to be graphed to 1 bar The measured data can be viewed by pressing the q left or right arrow keys The cursor will not move to the next graph point until the selected number of data points have been displayed numerically This facility allows up to 1024 numeric data points to be displayed for each graph cursor point and allows the user to observe an overall shape of the measured data on screen without the need for scrolling 7 7 99 e Autostore View the Autostore Leq Max and Min spec trum Locate Locate an Autostore ByTime record Next The next Autostore record Prev The previous Autostore record First The first ByTime record Last The last ByTime record Find Finds the specified ByTime record e Graph V Adjusts the vertical graph scale and offset Graph Level Allows numerical entry of graph level in dB Graph Scale Allows numerical entry of graph scale Graph H Adjusts the horizontal graph scale
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