Identification Of Nonlinear Parameters In Moving-coil Loudspeakers

With the improvement of living standard,electroacoustic industry has been developing rapidly.It is necessary for moving-coil loudspeaker,the mainstay of electroacoustic transducers,to improve itself.However,the intrinsic nonlinearity seriously influences the quality of sound reproduction.Nonlinear control of loudspeaker has always been the key subject of electroacoustic field.Compared with adjustment from structure,materials and others,digital technology means turns out a better choice currently.The acquisition of nonlinear parameters not only helps analyze loudspeaker,but also is crucial to nonlinear control of loudspeaker.This article acquires the nonlinear parameters of moving-coil loudspeaker with parameter identification method.Starting from the construction of nonlinear model,this article conducts nonlinear parameter analysis.The parameter identification algorithm is then designed by introducing system identification theory while subsequent results validate the algorithm.This article mainly includes three parts:In the first part,the nonlinear model of moving-coil loudspeaker,which includes the separation of linear part and nonlinear part,is built.This is the theoretical basis of the implementation of identification algorithm.In the second part,system identification theory is proposed.This article chooses gradient corrected methods as the identification algorithm and modifies this algorithm according to the nonlinear model mentioned above.Finally,a kind of identification algorithm based on current and voltage is figured out.In the third part,the reliability of this algorithm is verified through experiment.The algorithm is used to identify the nonlinear parameters of a full-range loudspeaker and a micro-speaker.Good agreement between measurements and identification results indicates that this algorithm can efficiently identify the nonlinear parameters of loudspeaker.Meanwhile,this algorithm has a fast computing speed.