A consideration of the elimination of nonlinear distortion of a loudspeaker system by using a digital Volterra filter

Abstract

The distortion of a speaker system at the 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 this 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, a Volterra series that describes the nonlinear input-output relationship is used to identify the audio playback system. A procedure for the design of an inverse system is proposed. In addition, a simulation is carried out. It was found possible to reduce the nonlinear distortion of a speaker system by as much as 100 dB by using the proposed method. © 1998 Scripta Technica, Electron Comm Jpn Pt 3, 82(1): 87–95, 1999