NONLINEAR DIGITAL AUDIO PROCESSOR FOR DEDICATED LOUDSPEAKER SYSTEMS

In this paper a non-linear loudspeaker model, which accurately reprodu ces the low frequency behavior, is presented. This description, derive d from an extension of the well known Small-Thiele equations, requires far less computational time and memory space than generic non linear structures. Moreover a noticeable further reduction of the number of o perations and of the memory cells required has been achieved by means of a multirate architecture. Inversion of the proposed model allows di gital prefiltering of the electrical signal in order to compensate for the non idealities of the electroacoustic conversion, The above filte r structure implemented on a digital signal processor, placed between the audio signal source and the power amplifier allows effective compe nsation of loudspeaker linear (both magnitude and phase) and non linea r distortion. Measurement results obtained with a commercial woofer ar e discussed.