Linking Large Signal Testing Between QC and R&D AN 65
Contents
1. Value Parameters rived from the relevant nonlinear curves These single values may be used for compar ing with the QC MSC module s output amp My Woofer LS Nonlinear Parameters Nonlinear Parameters o A Symbol Number Uni Comment Displacement Limits thresholds can be changed in Processing X BI Bl min 82 nit Displacement limit due to force factor va X C C min 9 mm Displacement limit due to compliance wa AL Z max 10 nm Displacement limit due to inductance vai Ad d2 10 nim Displacement limit due to IM distortion netry IEC 62458 Stiffness asymmetry Ak Apeak Symmetry point of Blo at maximal excu gt The value of x y Corresponds to the observations made in the Symmetry Point plot at higher displacement amplitudes To optimize the rest position the voice coil should be shifted approx 1 mm towards the back plate Parameter A indicates an asymmetry in the suspension of approx 25 as shown in the K x curve The displacement limits show the amount of displacement required for each nonlineari ty to produce 10 distortion Only xg and x are tested in production by MSC Note in this case the dominant nonlinearity is the inductance L x represented byx This is a coil design problem that will not be evaluated during the QC test KLIPPEL Application Note Page 5 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 5 State Conditions The LS result window State provides auxili2. Distortion by Shifting Voice Coil AN24 Measuring Telecommunication Drivers may download all KLIPPEL application notes here S13 QC Motor and Suspension Check MSC S1 Large Signal Identification LSI S2 Linear Parameter Measurement LPM Tutorial amp Manual MSC Tutorial amp Manual LSI Tutorial amp Manual LPM IEC 62458 Sound System Equipment Electroacoustical Transducers Meas urement of Large Signal Parameters W Klippel Mechanical Fatigue and Load Induced Aging of Loudspeaker Sus pension W Klippel Nonlinear Modeling of Heat Transfer W Klippel Loudspeaker Nonlinearities Causes Parameters Symptoms W Klippel Assessing Large Signal Performance of Transducers W Klippel Assessment of Voice Coil Peak Displacement Xmax W Klippel Nonlinear Damping in Micro Speakers S Hutt L Fincham Loudspeaker Production Variance presented at the 5 convention of the Audio Engineering Society 2008 San Francisco Most of the listed papers and many more related may be downloaded here Find explanations for symbols at 7 http www klippel de know how literature html K E B E e Last updated March 30 2015 KLIPPEL Application Note Page 13 of 13
3. Model Leach 2 Inductance Model adjust the MSC parameter Considerthermal heating C to match Consider nonlinear dam e To increase accuracy consider increasing the measurement Time especially for low frequency transducers To find the optimal test time start the meas urement using the maximal measurement time for best accuracy and then reduce the time step wise until the results start to deviate e Preloop defines the additional time spent to bring the speaker into steady state conditions e Compensate Amplifier accounts for the amplifier roll off at very low frequen cies In some cases results may be impaired if the applied boost is high Ampli fier compensation may be deactivated in most cases e Microspeakers or tweeters may heat up even during a short MSC test The re sulting variation of Re may impair the MSC results Consider activating Consid er thermal heating However this will result in a significantly longer test time to identify the thermal characteristic Therefore only use it if the results im KLIPPEL Application Note Page 8 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 prove e Consider nonlinear damping will account for the effect of nonlinear damping as a function of velocity R v This effect is relevant for micro speakers and should be activated for this transducer type More related information can be found in the section Root Causes of Result Deviation and in the MS
4. testing limits is not covered Please refer to the MSC Manual for more information The device under test DUT does not necessarily have to be a good reference unit when used for relative limit calculations You are encouraged to test multiple units for assessing variations and double checking the settings applied The speaker used in this example is a conventional woofer with an overhung coil configuration 2 1 Linear Parameter Identification R amp D LPM Measurement The Linear Parameter Measurement is accurately identifying the lumped parameters of the transducer s linear equivalent circuit T S parameters etc Both LS and MSC require a mechanical calibration factor to display the result in abso lute mechanical units mm Either the moving mass Mms or the force factor at the coil rest position Bl x 0 can be used for this purpose Both can be measured with opti mal accuracy using LPM Please refer to LPM Tutorial for detailed instructions about setting up an LPM measurement Either the laser or the added mass method can be used with LPM LPM Results After the LPM has finished successfully the resulting Bl and Mms can be found in the result window Table Linear Parameters My Woofer LPM Table Linear Parameters Name Value Mechanical Parameters using laser Mims 11 318 Wimd Sd Rms 1 568 Cms 0 369 2 7 3 033 Lambda s 0 042 Unit g kgs mm M N mm M A Comment mechanica
5. C Tutorial section Customize your MSC Task 8 Final Setup The screenshot below shows the results with optimized setup parameters A lower Check voltage has been used to reduce the peak displacement and the measurement time was increased to improve accuracy Coil Offset 0 9829 mm ld Nonlinear working range not reached symmetrically Coil Offset m recommended shift to o Stiffness Asymmetry stiffness asymmetry fs resonance frequency Re electrical voice coil res Qts total Q factor Xpeak 5 37 mm peak displacement during measurer Xprot peak displacement of reference Dut xac 4 38 ac displacement at coil offset xde 0 38 de displacement at maximum peak BI min 53 3 9 minimal force factor ratio during me Cms min 52 6 9 minimal compliance ratio during mea Now the Coil Offset is slightly less than the Xsym value stated in the LSI Nonlinear Parameters table However using the cross cursor in LSI s BI Symmetry Range plot shows a very good agreementwith the x value provided in MSC s parameter table E S Nonknesr Parameters El Symmetry Rang e 4 3943 0 97472 BI Symmetry Range A ry Point Asymmetry 5 KLIPPEL oll out gt gt se an i UU l i i i i 1 lt lt CoIin 0 1 2 3 4 X ap Amplitude mm y 9 Verify Setup In order to verify the test setup parameters when multiple speaker samples are available it is recommended to run the QC test on the co
6. C System e QC Standard e Production Analyzer e Power amplifier e MSC Motor amp Suspension Check The following relevant large signal design and end of line testing parameters are relat ed to suspension spider surround and motor B field distribution and voice coil and can be separated into base and derived parameters Motor Parameters e Force factor at rest position Bl 0 e Nonlinear Force Factor Bl x e BI Symmetry Point Xsym e Coil Offset Xoffset e Peak displacement limited by motor xp Suspension Parameters e Nonlinear Stiffness K x e Stiffness Asymmetry Ans e Peak displacement limited by suspension xc All listed measures comply with EC 62458 Other parameters such as nonlinear induct ance and losses are mainly defined by design and are not considered as relevant for end of line testing For parameter definitions please refer to the references in the module s user manual Note implementation of derived nonlinear parameters may differ slightly between MSC and LSI i e due to different reference peak displacements Base parameters KLIPPEL Application Note Page 2 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 2 Step by Step Guide The following procedure outlines the general approach for setting up and evaluating the results of a QC MSC test based on R amp D measurements from one or more reference speakers These instructions mainly focus on finding an optimal test setup generating
7. FRY Aili OG 1 I OV cere tac ert cscs eco a ea cae ioe we ee een neat esa eee ecm ees Linking Large Signal Testing Between QC and R amp D AN 65 1 Scope Motivation Objectives Device Under Test Requirements Parameters Different measurement principles and conditions exist between R amp D and QC re sulting in different ways to present the nonlinear transducer parameters While QC requires speed robustness and simplicity R amp D requires a more in depth detailed analysis Linking both processes is crucial for successful consistency and meaningful testing In addition to understanding and handling differences between R amp D and QC the objectives are e Setting up end of line testing MSC based on R amp D measurement results using reference speaker s e Ensuring comparable and reproducible results e Optimal balance of accuracy and test speed on the production line e Dealing with different motor geometries Electrodynamic transducers operated in free air or mounted in a sealed or vented en closure Both KLIPPEL R amp D and QC systems are prerequisites The following lists represent the minimal though complete configurations KLIPPEL R amp D System e Distortion Analyzer e Power amplifier e Laser sensor optional e LPM Linear Parameter Measurement e LSI Large Signal Identification Woofer Tweeter or Box depending on DUT type from version 206 x for derived nonlinear asymmetry parameters KLIPPEL Q
8. Linking Large Signal Testing AN 65 Between QC and R amp D Application Note for the KLIPPEL R amp D and QC SYSTEM Document Revision 1 2 The large signal performance of loudspeakers is limited by nonlinear and thermal mechanisms Transducer nonlinearities limit the acoustical output affect the speaker system alignment cause unstable behavior and create audible nonlinear distortions such as intermodulation and harmon ic distortion The nonlinear characteristics depend on important parameters such as voice coil offset which can vary during the production process Therefore it is important to optimize the nonlinear speaker parameters during the design and test for conformity in production However these processes can be very different To help provide consistent and comparable results this document explains the link between the KLIPPEL R amp D LS and QC MSC systems which provide measurements such as large signal identification and voice coil offset testing respectively FAIL Force factor BI X Corrected 4 Coil Offset 0 56 mm Rest Position i gt Detected 2 Coil Offset E 4 2 0 2 4 lt lt Coil in X mm coil out gt gt CONTENTS Sten Ey oep G1 0 eae ne a en R ee ee ee eee eee ene 1 2 3 Root Causes Of Result DEVIATION cceseeccccccccsessseecccecssseeeeeceeessaaesseeeceeessseesseeceeeessaeassseseeesssaaaseseceeeesaagees 4
9. ary information reflecting the state condi tions during the measurement My Woofer LSI Nonlinear Parameters State A Symbol Value Unit Comment Deita Tv Delta Tlim 33 1 60 0 K increase of voice coil temperature limit Bimin Bllim 50 2 50 0 minimal force factor ratio limit Cmin Clim 50 2 50 0 minimal compliance ratio limit P Plim 9 5166 20 000 WwW real electrical input power limit Lmin 70 1 minimal inductance ratio Pn wW IMPORT Zn at Driver page to see nominal electrical inpt P Re 7 920496 W Power heating voice coil P Mech 1 217842 W Irms 1 375 A rms value of the electrical input current V rms value of the electrical voltage at the transducer tern Ipeak 4712 A peak value of the electrical input current Upeak 25 268 V peak value of the electrical voltage at the transducer ter Glarge Gmax 15 2 26 0 dB gain of the excitation amplitude increased in the large s Mech system abs import used to identify mechanical system in absolute mm dc component of voice coil excursion measured in the mm positive peak value of voice coil excursion measured in mm negative peak value bottom of voice coil excursion mt mm upper limit of displacement range 99 probability mm lower limit of displacement range 99 probability mm maximal voice coil excursion allowed by protection syst m s voice coil velocity Displacement amplitude information such as the protection displacement limit Xprot sh
10. bsolute mechanical units e g mm LS facilitates im porting a reference value such as the force factor at the rest position Bl x 0 or the total moving mass M These parameters are measured accurately with high precision by LPM During end of line testing Bl x 0 or Mms are usually not updated for each unit tested Therefore to calibrate the variations between samples MSC also facilitates the entry of a typical reference value This means that any deviation between the measured and typical values indirectly affect the results such as xz or voice coil offset The relative error between measured displacement x and typical displacement x is described by the following relations 1 X Bly e Mms DUT s typ As shown a Bl deviation causes a linear error while a moving mass deviation has less of an impact square root In terms of typical production processes force factor is often more stable than moving mass However Bl x 0 strongly depends on the rest position by defi nition importing mass may be more robust Note A typical end of line test includes small signal parameter and acoustical response measurements Parameters such as resonant frequency or average sound pressure level will indicate a significant deviation in BI x 0 or Mms 3 8 Test Setup Load During end of line testing test boxes are commonly used to provide consistent measure ment conditions and ambient noise isolation Because R amp D tests ar
11. ct the speaker with correct polarity The window below shows the B Symmetry Range and Symmetry Point plot which pro vide additional diagnostic information about BI asymmetry and coil positioning KLIPPEL Application Note Page 4 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 My Woofer L I Nonlinear Parameters Bl Symmetry Range BI Symmetry Range ES Symmetry Point Asymmetry 5 ZOOM KLIPPEL Amplitude mm At low displacement amplitudes the field asymmetry is dominant because the sym metry point Xsym Xac red dashed curve varies with rising amplitude At higher excur sions the symmetry point Xsym Xac Xp approaches a stable value of approx 1 mm green line indicating a non optimal voice coil rest position which significantly limits the working range of the driver Due to the field asymmetry the voice coil offset can only be estimated correctly at very high displacement amplitudes This must be considered when setting up MSC because using the symmetry point measured at lower displacement amplitudes would be mis leading Note Some motor designs require special attention when testing voice coil offset For details about the most common voice coil configurations and the corresponding BI Symmetry Range and Symmetry Point plots please refer to application note AN1 Op timal Voice Coil Rest Position 4 Derived Single The LSI result window Nonlinear Parameters contains single values that have been de
12. displacement xXpeak in MSC refers to the maximal absolute displacement which should be to the LSI reference displacement Xprot which has been identified according to the user defined protection limits Therefore it is recommended to reduce the MSC stimulus voltage in order to decrease the peak displacement by 1 4 mm Blmnin is an indicator of the degree of nonlinearity because it describes the force factor variation Bl x related to the Bl at the rest positionBl x 0 In this example Blmin is below the LS protection limit of 50 which is another indication that the MSC stimu lus voltage should be reduced Note To estimate a valid voice coil offset the MSC measurement looks for a symmet rical force factor reduction of 70 or greater In some cases when B x is highly asym metric the warning message Nonlinear working range not reached will be displayed However if the results can be validated by comparing MSC state variables to LS the warning can be ignored Separate Xpeak ANd Xpottom Available from version QC4 0d In some cases it may be necessary to edit additional venced F start parameters to improve the agreement between re Fase sults Selecting the Advanced option activates the fol Resolution lowing additional hidden parameters Time 2 73 s Preloo 0 5 e lf linear parameter estimation of the MSC fails P z pa Compensate Amplifier C or LPM shows a clear preference for a specific inductance
13. e typically performed in free air or in a baffle the acoustical load conditions during a QC test may be different The enclosed air acts as an additional spring which increases the total measured stiffness and limits peak displacement The actual impact depends on the DUTs radiating surface area and the volume of the test box In most cases increasing stimulus voltage is sufficient to compen sate for the drop in peak displacement In some cases even large signal parameters may be corrupted For example in very small test boxes air compression becomes nonlinear At the same time a dominant air stiffness may linearize the total Kms x 3 9 Ambient Conditions Since temperature and humidity variations may have significant effects on suspension pa rameters and other characteristics all tests should be performed under the same climatic conditions Although factory conditions can be drastically different from laboratory condi tions it is important to at least provide the same climate conditions during setup and evalua tion stages KLIPPEL Application Note Page 12 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 4 Related Information Application Notes You Specifications Manuals Standards Papers AN1 Optimal Voice Coil Rest Position AN2 Separating Spider and Surround AN3 Adjusting the Mechanical Suspension AN5 Displacement Limits due to Driver Nonlinearities AN21 Reduce
14. fer Voltage rms 7 5 Calibration Relative _ Mms Import e Bl import Bl x 0 5 Advanced a Settings such as measurement time frequency range and resolution are set automati cally in the background The complete set of available settings is shown by selecting Advanced parameter In most cases the template settings are suitable or a good start ing point One of the most critical setup parameters is the excitation Voltage since it defines the peak displacement during the measurement Although the excitation signals of LS noise and MSC multitone differ both have comparable characteristics Therefore Ums as displayed in the LSI State window see section State Window may be used as a reasonable test voltage for the first run of MSC For mechanical calibration either Bl x 0 or Mms can be copied from the LPM meas urement Select the corresponding parameter in Settings Calibration It is recommended to use the most stable parameter i e the parameter which exhibits the least amount of variation amongst a series of sample drivers in production Import ing moving mass may be preferable as it is independent of the coil rest position Further aspects are discussed in section Root Causes of Result Deviation If Relative calibration is selected all results will be displayed in of peak displacement This is not recommended due to the lack of diagnostic information in the result After selecting the desired res
15. l mass of driver diaphragm assembly including air load mechanical mass of voice coil and diaphragm without air load mechanical resistance of total driver losses mechanical compliance of driver suspension mechanical stiffness of driver suspension force factor Bl product suspension creep factor These parameters may be exported to the clipboard as shown below Into Diver Stimulus Input All Settings Import from Clipboard Export to Clipboard KLIPPEL Application Note My Woofer LPM Method Im Export Known Yalues Blis 0 N A _ Mms g Re 0hm Page 3 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 2 2 Large Signal Parameter Identification R amp D 1 LSI Measurement 2 Nonlinear Curves 3 BI Symmetry Point Import the mechanical calibration parameters BI 0 or Mns as shown below My Woofer 2a LSI Nonlinear Parameters Info Driver Generator Protection Conditions ImExport Series w Force factor BI 0 5 03 N A Moving mass ha a 11 52 g Moice coil resistance Re Delta Tv 0 3 69 Ohm Import from clipboard Export to clipboard Help Cancel This is required to display the results in absolute mechanical units e g mm Using a laser sensor with LS is optional When using a laser sensor with LS importing LPM parameters is not required but recommended for better accuracy Please refer to LSI Tutorial for detailed instructions on how to setu
16. mplete sample lot This helps verify typical variations accuracy stability and limit settings KLIPPEL Application Note Page 9 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 3 Root Causes of Result Deviation 3 1 Peak Displacement Comparing derived nonlinear pa rameters such as voice coil offset or Symmetry Point stiffness asymmetry may heavily KLIPPEL depend on the peak displacement 20 achieved during the measurements Xsym 2 MM Xsym 3 5mm This is especially the case for non 2 5 A A linear characteristics with a domi nant inherent asymmetry BI Symmetry Range Coil out gt gt ___ Offset Therefore the maximum displace ment during both measurements 2 5 should be the same lt lt Coil in Note there are different parame aa ters referring to peak displacement which should be distinguished such ES eee CC ASX peak Xbottom Xac Xprot Xp For very linear motor designs always check that displacement is high enough to produce flanks on both sides of the nonlinear curve even when assuming high offset This policy of producing flanks should also be followed when the nonlinear curve has two sub maxima and a local minima See AN1 for more details In order to be determine displacement limit parameters such as x andxp a certain amount of variation is required 3 2 Measurement Duration and Excitation Signal The LS measurement takes significant time to Dis
17. nts The influence of gravity on the coil rest position can be estimated by the following equation AX offset E Mms Cms The offset is given relative to vertical orientation 3 4 Polarity Although it is not relevant towards determining the actual nonlinear identification polarity is important to correctly orient an outward coil movement with a positive voltage on the posi tive terminal of the speaker If a laser sensor is used during the LSI measurement the polarity is automatically determined However a correct polarity connection is recommended to have consistent orientation of the nonlinear curve abscissa Due to the lack of mechanical sensors WSC relies on correct con nections The wrong polarity connection during MSC can be detected as an inverted sign in the offset result 3 5 Time Variance amp Ageing The material properties of the suspension change with the amount of mechanical work per formed i e stress and strain during operation As a result the mechanical parameters small and large signal vary with time as shown in the example K t plot below The changes can be irreversible For example the quick stiffness decay during the break in period of new transducers A change in suspension stiffness may produce a change in coil rest position Therefore LSI should be performed before MSC In LS both the initial and final coil rest position is indicated by vertical lines in the nonlinear parameter charts Force facto
18. ould be stated along with the derived nonlinear parameters Ax OF Xgym Xoffset This ensures comparability between results since Ag and Xsym Xoffset are determined at high displacements In addition these state conditions help estimate the start and target values terminal voltage peak displacement required Bl decay to set up the QC MSC test for compara ble results 2 3 Setting up the QC Test 1 Create Select Test The LS results can be used to set up the QC MSC test in an end of line test environ ment The test setup may be different because the QC measurement is usually per formed with the DUT inside or attached to a test box instead of free air For best com parability of the results it is recommended to keep the same mounting orientation and load large test box as used during the LS test Note It is important to connect the DUT with correct polarity Otherwise some nonlin ear parameters and states will have the wrong sign when compared to LSI Open QC Start Engineer and create a new test based on a suitable template or select an existing test which shall be enhanced by the MSC for large signal testing Click Measure to login for setup KLIPPEL Application Note Page 6 of 13 Linking Large Signal Testing Between QC and R amp D Click Add under Property Page Tasks to add the MSC to the test sequence Use the arrow buttons to change the order of the test sequence 2 Add MSC Task In a reverberant test envi
19. p a new LS operation To obtain the nonlinear parameter set define suitable Protection Parameters and perform the LSI measurement according to LS Tutorial The relevant LS result windows nonlinear force factor Bl x and the nonlinear stiff ness K x are shown below in the final state of the measurement time cursor in Temperature Power result window is located in the final position i My WoofenLl3 Nonlinear Parameters Bl X z amp My Woofer L Nonlinear Parameters Kms x o amp amp Force factor BI X Stiffness of suspension Kms X 00 15 05 00 15 05 ees pe prol Xp lt x Ape es e lt prot xp lt ap Bi X Kms KLIPPEL 2 KLIPPEL The colored lines represent the nonlinear parameters within the displacement range Xprot defined by the protection parameters The black lines indicate the displacement range X lt X lt Xp with a 99 probability of occurrence only for time cursor located in final position The BI x plot in this example shows a visible offset from the rest position at x 0 along with a slight field asymmetry The suspension tends to be asymmetric as well Note The orientation of these curves depends on the polarity connection during the measurement In case a laser sensor is used coil in and coil out markers indicate the actual physical orientation of the parameters However for consistent comparabil ity reasons it is recommended to always conne
20. place ment PDF X histogram 00 08 27 adaptively determine the nonlinear parame EE PDF x PDF X ters with a broad band noise signal The LS 0 25 p an EPRE displacement PDF histogram shows low voice i coil displacement most of the time Relatively i speaking there are very few incidents of high excursions However especially high ampli tude information is required for nonlinear 99 l l l l I l l identification purposes If probability f interval Contrast to LS MSC must acquire all infor mation in only a few seconds Therefore a dedicated multitone signal is used to ensure symmetric peak displacement and a low crest factor at minimal test time During this short test time peak displacement is only achieved a few times Therefore increasing time is recommended to improve the result agreement The default settings of the Driver Type templates may not be time optimal for your transduc er especially when the resonance frequency of the DUT is in the lower recommended range of the selected template KLIPPEL Application Note Page 10 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 3 3 Orientation Due to a soft suspension or a large moving mass the effects of gravity may impair the results by causing a significant shift in the coil rest position Therefore It is recommended to always keep the DUT orientation similar to the target application and maintain consistency through out all the measureme
21. r BI X 00 32 42 mus Xprot lt X lt Xprot me Xp lt X Xp BI X 0 25 E aii 7 KLIPPEL 0 20 ma i E 0 15 J a N S 0 10 5 Speaker 1 eer final original coil rest coll rest 0 05 me 0 20 40 60 80 100 120 140 160 180 hour 0 3 0 2 0 1 0 0 0 1 0 2 0 3 lt lt Coil in X mm coil out gt gt KLIPPEL Application Note Page 11 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 3 6 Self Heating In order to identify the large signal parameters during LSI the device under test is usually operated close to its mechanical or thermal protection limits As a result the measurement is compensated for an increase in D C resistance R due to voice coil heating Voice coil heating may also occur during MSC The setup parameter Consider thermal heating may be used to compensate but this increases measurement time significantly by factor 3 and it is not required in most cases Typically only micro speakers or tweeters may suffer from heating during the MSC test because the thermal time constant of the voice coil T is relatively fast Therefore keep the measurement time as short as possible or activate ther mal mode when the results are not reliable Note LSI provides an optional Thermal Mode which is performed after nonlinear parameter identification to identify thermal parameters such as T 3 7 Variance of Mechanical Calibration To calibrate the result parameters in a
22. ronment it is QC ac Info Tasks Limits Login Tasks Language EN f Cortrok Start Impedance Sound Pressure PNI L Cortrot Finish 3 Set Driver Type 4 Set Initial Test Voltage 5 Mechanical Cali bration 6 First Run KLIPPEL Application Note not recommended to place MSC right before an acoustic test step like Sound 5 Pressure as its high level acoustical et decay may falsify the Rub amp Buzz test Add new task tT amp QC gt Standard Note For minimal overall test time the MSC should be placed early in the test sequence Signal processing for MSC is performed in parallel with subsequent measurements Organisieren v Neuer Ordner 10 task kib leakDetection task kib precond 0001 task kib l Controt Start e Motor Suspension Impedance Sound Pressure PMI L Controt Finish Set up MSC by selecting one of the predefined Driver Type templates Select the template according to the specified resonance frequen cy range of the DUT See the MSC Tutorial section Find the Optimal Driver Type for more information Add Remove Parameters The present DUT s resonance frequency is ae below 80 Hz thus the Subwoofer template is recommended The Woofer template would be applicable as well but it is recommended to use the lower template as it uses more reliable settings such as longer measurement time for better low frequency resolution Driver Type Subwoo
23. ults such as Coil Offset in parameter category Measure ments start a first measurement to verify the setup parameters by clicking the Start button in Control Panel The Summary window shows the results of the MSC with the estimated Coil Offset printed at the top The value is a close match to the x y value measured by LSI even when just using the standard QC template settings In addition Stiffness Asymmetry Page 7 of 13 Linking Large Signal Testing Between QC and R amp D AN 65 7 Modify Ad vanced Settings shows good agreement withA TASK OUTPUT MOTOR SUSPENSION E Coil Offset 1 010 mm Nonlinear working range not reached symmetrically force factor dropped to 70 8 target lt 70 increase voltage Name 5 Jesi YE Coil Offset mm recommended shift to compensate voice coil offset Stiffness Asymmetry stiffness asymmetry fs Hz resonance frequency Re Ohm electrical voice coil resistance at DC Qts total Q factor Xpeak 6 82 peak displacement during measurement Xprot z 7 peak displacement of reference Duts xac 5 81 ac displacement at coil offset Xde 0 74 dc displacement at maximum peaks BI min 48 5 y minimal force factor ratio during measurement related to rest pa Cms min 42 4 minimal compliance ratio during measurement related to rest po The state variables shown in the second table should be checked to verify that the MSC measurement conditions are the same as LS measurement conditions Peak
Download Pdf Manuals
Related Search