A note on the filtering equalization in large multiactuator panels

Multiactuator Panels (MAPs) are flat loudspeakers that can be used to build arrays for Wave Field Synthesis (WFS), alternatively to classical dynamic loudspeakers. The sound radiation of these loudspeakers is a complex superposition of excited modes that vary strongly with frequency. Therefore, the characteristic MAP spectrum is very irregular and needs to be equalized to obtain a flat, colorless response. In this paper, an efficient digital equalization method is applied successfully to the problem of spectral equalization of MAPs. It is based on a chain of second-order sections of infinite impulse response parametric filters with very low computational cost. The method compensates for the measured MAP response in order to achieve a desired frequency response. The equalization process has been applied to a large MAP prototype, comprising a large number of exciters within a panel. A dedicated exciter equalization and its consequences on the filtered responses have been addressed.