Simulation of the impulse response between a single source and multiple, closely‐spaced receivers in a reverberant room

Abstract

In considering the design of multimicrophone hearing aids, it would be useful to have a simulation of the effect of a reverberant room on the acoustic signals received at closely spaced microphones. The image method, as described by Allen and Berkley [J. Acoust. Soc. Am. 65, 94–950 (1979)], can be used for this purpose, but faithful simulation of intermicrophone phase requires a modification of the algorithm. Specifically, rather than quantize impulse arrival times, an analytic low‐pass time function is used to extrapolate the effect of an impulse arrival to nearby sampling times. While Allen and Berkley's original method gives rise to errors in arrival time of up to one‐half the sampling interval, the modified method approaches zero error. The low‐pass time function can be viewed as the impulse response of a low pass anti‐aliasing filter. The choice of this filter is governed by considerations of computation time, the phase added by the filter, and filter cutoff characteristics. [Work supported by NIH.]