Automatic filter design for 3-D sound movement in embedded applications

Abstract

In this paper, we propose an automatic method of designing digital filters for three-dimensional (3-D) sound movement that is dedicated to embedded applications. By this method, read-only memory (ROM) capacity and computational load are reduced with only slight degradation of the 3-D sound effect. For practical applications of 3-D sound, the continuous movement of a virtual sound image is indispensable. To achieve 3-D sound movement, the interpolation of filter coefficients is often required; however, the frequency response of an intermediate filter obtained by interpolation is severely distorted using conventional automatic design methods. The proposed method reduces this distortion by evaluating the response of the intermediate filters in the optimization process. The results of objective evaluation and subjective listening tests show that the proposed method improves the perceptual quality of 3-D sound movement, even with runtime interpolation of filter coefficients.