Experiments on the universality of the most preferred reverberation time for sound fields in auditoriums.

Abstract

In this paper, it is confirmed that the most preferred reverberation time is approximately expressed by [T_<sub>]_d &sime;23τ_e(s) where T_<sub> is defined by a decay rate to decrease 60dB after the early discrete reflections and τ_e is the effective duration of the autocorrelation function(ACF) of source signals defined by the delay at which the envelope of normalized ACF becomes just0. 1. Also, it is shown that the most preferred reverberation time is independent of the total amplitude of both early reflections and reverberation relative to that of the direct sound, and is independent of the magnitude of the interaural crosscorrelation(IACC). As is widely accepted, more preferred condition can generally be obtained by minimizing the magnitude of IACC. The maximum values of the crosscorrelation, however, must be maintained at τ=0 to ensure frontal localization of the sound source.