A consideration on elimination of nonlinear distortion of the loudspeaker system by using digital volterra filter

Abstract

The distortion of the speaker system, as the terminal end of an audio playback system, can be divided into linear distortion and nonlinear distortion. The authors have carried out research on elimination of linear distortion by using digital filters. In such a process, when the equalization effect at low frequencies is increased, the amplitude of the speaker vibrating plate increases so that the nonlinear distortion increases. Therefore, in order to construct a high-fidelity audio playback system without distortion, it is necessary to eliminate nonlinear distortion in addition to linear distortion. To this end, the Volterra series that describes the nonlinear input–output relationship is used for identification of the audio playback system. A procedure is proposed to design an inverse system. In addition, a simulation is carried out. As a result, it is possible to reduce the nonlinear distortion of a speaker system by as much as 100 dB by the proposed method, confirming the usefulness of the method. © 1999 Scripta Technica, Electron Comm Jpn Pt 3, 83(2): 110–118, 2000