Nonlinear IIR filter considering nonlinearity of self-inductance of loudspeaker systems

In this paper, we propose a novel nonlinear IIR filter considering the effect of the self-inductance in loudspeaker units in order to compensate the nonlinear distortion. The nonlinear IIR filter proposed by Takemura, et al. includes the nonlinealities of the force factor and the stiffness of the suspension except the self-inductance of the voice coil in loudspeaker units. This means that the conventional nonlinear IIR filter cannot compensate the nonlinear distortion at high frequencies due to the self-inductance. In contrast, the proposed nonlinear IIR filter which considers the nonlinearity of the self-inductance can compensate it. The parameters of the closed-box loudspeaker system are estimated using Simulated Annealing (SA), and the proposed nonlinear IIR filter is designed according to the corresponding estimated parameters. Experimental results on the compensation for the nonlinear distortion demonstrate that the proposed nonlinear IIR filter can reduce more nonlinear distortion compared with the conventional one.