Analysis of multiple listener equalization performance due to displacement effects

Traditionally, room response equalization is performed to enhance sound quality, by reducing the effects of reverberation, at a given listener. However, room responses vary with source and listener positions. Hence, in a multiple listener environment, equalization may be performed through averaging the room responses measured at multiple listener locations. However, the performance of averaging based equalization, at the listeners, may be affected when listener positions change or due to microphone-listener position mismatch (i.e., displacement effects). In this paper, we present a statistical approach to map variations in listener positions to equalization performance of spatial average methods. The analysis is done at frequencies above the Schroeder frequency where the direct and the reverberant sound fields are uncorrelated, and the results are presented in a 3-D plot to clearly show the changes in equalization performance (in dB’s) versus mismatch and frequencies for various listener configurations relative to a fixed loudspeaker source. The results indicate that, for the analyzed listener configurations, the zone of equalization depends on distance of microphones/listeners from the source and the frequencies in the sound. [Work supported by the U.S. Dept. of Army.]