Nonlinear signal processing for compensating nonlinear distortion of louspeakers

In this paper, we propose a 3rd-order nonlinear IIR filter for compensating nonlinear distortions of loudspeaker systems. The 2nd-order nonlinear IIR filter based on the Mirror filter is used for reducing nonlinear distortions of loudspeaker systems. However, the 2nd-order nonlinear IIR filter cannot reduce nonlinear distortions at high frequencies because it does not include the nonlinearity of the self-inductance of loudspeaker systems. On the other hand, the proposed filter includes the effect of such self-inductance and thus can reduce nonlinear distortions at high frequencies. Experimental results demonstrate that the proposed filter can realize a reduction by 3.2 dB more than the conventional filter on intermodulation distortions at high frequencies.