New Trends in Modeling and Identification of Loudspeaker with Nonlinear Distortion

This paper provides recent developments in modeling and identification of nonlinear systems pertinent to loudspeaker with nonlinear distortion effect. It is known that when small loudspeakers are driven at high playback levels the nonlinear characteristics of these speakers become a major source of sound degradations. Consequently it is essential to find a good model that matches to the loudspeaker response for the purpose of predicting and preventing the nonlinear distortion. This becomes particularly important for the purpose of improving sound quality of mobile phones. This paper presents the loudspeaker operation, the issues of concern, and nonlinear modeling techniques that can reliably be used for its identification process. Frequency domain and state-space modelings are considered and emphasis is given towards polynomial nonlinear state-space models which can better tie to nonlinear identification of loudspeaker.