Influence on Sound Image Localization of Phase Characteristics of Approximated Head-related Transfer Functions Using IIR Filters.

A simple method based on IIR filters that approximates HRTFs (head-related transfer functions) has previously been proposed for realizing sound image localization. The purpose of this paper is to clarify the influence of the nonlinear phase characteristics of the IIR filters on the sound localization. First, the effectiveness of this method was verified by carrying out sound localization experiments using the approximated HRTFs for the direction sensation of a sound image on a horizontal plane in a two-loudspeaker reproduction. Next, localization experiments were carried out to investigate the influence of the phase characteristics on the localization by using both pink and narrow-band noises. The results showed that the influence, although it was dependent on the frequency band, was about 5 degrees on average, and the maximum was 10 degrees.