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1、扬声器等效模型You can simulate the behaviour of a speaker and its crossover by professi onal speaker desig n software. In case you do not have access to these software, an alter native would be to use the SPICE simulatio n software to do the speaker simulatio n. Here I will dem on strate how to do this usi
2、ng OrCad.There is a demo version of OrCad release 10 which you can download from Orcads web site to try.Thiele-small eqivale nt circuitBefore you can simulate your driver in Orcad, you n eed to calculate the eqivale nt circuit for your driver unit. This circuit can be derived from the Thiele-small p
3、arameters.For example, if a driver has the follow ing Thiele-Small Parameters :Thiele-Small ParametersRevc5.8 ohmsDC resista nee of voice coilLevc0.55mHvoice coil in ducta neeBl6.5T.mforce factorQts0.35total QQes0.45electrical QQms1.55mecha ni cal QFs37 Hzres onant freque ncyMmd0.014 kgmass of cone
4、+ voice coil + etcRms2.08resista nee of suspe nsionCms1.34 mm/Ncomplia nee of suspe nsionSd0.0136sq.meffective cone areaVas0.0347cu.mequivale nt acoustic volumeXmax0.004mlin ear travel of voice coilFR37 -5000kHzfreque ncy resp onseVd0.0005cu.mdriver un it volume displaceme ntThen this driver can be
5、modelled with the following circuit :+Lc-r5 卄二:21.21 J7Some of the circuit values above are already obvious. Veg representsthe amplifier and is assumedtohave no output resista nee. The remai ning values were calculated from,Cmes = Mmd/(BI*BI) = electrical an alog of driver mecha ni cal cone massLces
6、 = Cms*Bl*Bl = electrical an alog of driver mecha ni cal suspe nsion complia neeRes = Bl*Bl/Rms = electrical an alog of driver mecha ni cal suspe nsion resista nee Cmef = 8*po*Ad*Ad*Ad/(3*BI*BI) = electrical analog of air load on the driver units cone where:po = air den sity = 1.18 kg/cu.mAd = effec
7、tive radius of the driver units cone = Square Root of (Sd/3.14)Some of these parameters can be look up from the drivers specification. This missing one could be calculated using the Un ibox excel file. Uni box is a free tool that can help you to desig n speaker en closure.drive Unit Farsmeters1J (La
8、)讪LU帕 No min日 I PcivverFafameteri orf Si nlt UnitWPL at 1 W 1 mi deEPLst 2.S3 Vrws 1?Mbk SFLst 60 W106.1 dIBQts0.339Ettfeetl Cits0.339lYlms13.02 gCms1.6S2 mrn/lH口 EM1.H20 kg/sElBSD TmRf. efficiency! nD0.415 %Ettieii-sncy. n0.415 %Applied voltage13.73 YTrns匚on startsf i g TinUniBox UniriEd Bon Mod电IF
9、ar引orr斗力卓守胖加胡羽書Kf姑血 阖aantf MOO - 缈3Sound WgodAir DfeFigltj/Qmie Ch/EcliQ?MjOU hte亍划朴Ohm 仙 : 伽.0品臣4迈丨潮rniT1CIJOOmHIOjOOOiw60 0W1.181 00_I6EM削FiMl Com口anmntE21(Rct2)OjOO Ohm25(Cgo2)0.00 uFz?10 7 I匚loa：ed Eok口.0口 OhmCim mHO.OCi CHim .OOliF 口-口口 eH21RE Cc1) |Lco21Dnvfe Urilt Nondirettisnal Rangeall conr
10、tants to default values曲me |Fw |口巨mi QB Datm Pm兰昌rive Unit CcnfigurationFR NfTctEd by L旦L旦乞冃旦2：FR atfwctwT By WKtsrn曲 gq；ReadyVbUFL迪 PP啊130.0I i VIEl MGSowker Dezci门 /flo迫dVented Box /PR BaocBoxtdttlNUMSpeaker Driver Unit Simulatio nAfter you created your driver models, you could start by testing if
11、 your driver models impedance response is similar to your drivers actual impedance response. Now you need to familiar yourself with OrCad if you have not used it before. Here is a great Orcad tutorial that I suggest you to read if you have not used Orcad before.You can save some time by dow nl oad i
12、ng my Orcad project a sin gle driver un it, just cha nge the RLC values and you can start trying OrCad simulation right away.Lets do the woofer as an example. First, start up Orcad Capture and create a new empty project. The n in the schematic draw the driver model using Place-Part. comma nd. The R,
13、 L and C are all un der theANALOG library. (You may need to add all libraries first if you have not done it.) Then add the AC voltage source (called AC un der the SOURCE lib.) and also add a ground refere nee by Place - Groun d. - O/Source. Connect all comp onents by Place-Wire. You should now have
14、a circuit similar to the one below :込 Capture CIS - Demo Edrtion |X3e Edit yevj Bsce 巴白cfo Ppice Icoessories 2F*tions 述inda啊 Helpn xCP/ (SCHEMATIC1 : PAGE1)oLets do some simulatio n: Add a new simulatio n pro select PSpice- New Simulatio n Profile, type in a name. A simulation settings dialog will p
15、op up. In the Analysis tab, set Analysis type to AC Sweep/Noise. Select Logarithmic, start freque ncy of 10H z, End Freque ncy of 20kH z, Poi nts/Decade to 50. Click OK.Simulation Settings - testAndlysis Configuration Files Options Data Col tec HonFroLe WindowAnali*d: p*| AC Gweep4d&iseOptions:S General GettingfCtLimeafLogs rithnicD迪朮A匸 Siveep T
