Modification of second-order nonlinear IIR filter for compensating linear and nonlinear distortions of electrodynamic loudspeaker

摘要

In this paper, we propose a modified 2nd-order nonlinear IIR filter for compensation of both linear and nonlinear distortions of electrodynamic loudspeakers. A nonlinear IIR filter is a nonlinear compensator and is based on a physical nonlinear model of electrodynamic loudspeakers. However, it is difficult to compensate nonlinear distortions when a loudspeaker has large sharpness at the lowest resonance frequency, at which the displacement of the diaphragm becomes large. Although it is necessary to compensate the sharpness of the loudspeaker, the nonlinear IIR filter cannot compensate the sharpness because it does not have a linear filtering feature. In this paper, we propose a modified 2nd-order nonlinear IIR filter that can compensate not only the nonlinear distortions but also the sharpness by employing the linear characteristics of the loudspeaker with the desired sharpness. Experimental results show that the proposed filter can compensate the linear and nonlinear distortions more effectively than a conventional filter.