Subband adaptive filtering applied to acoustic feedback reduction in hearing aids

Abstract

Acoustic feedback is a problem in hearing aids that contain a substantial amount of gain, such as hearing aids that are used in conjunction with vented or open molds and in-the-ear hearing adds. Acoustic feedback is both annoying and reduces the maximum usable gain of hearing-aid devices. This paper models the time-varying acoustic feedback path for hearing aids before performing a systematic evaluation of acoustic feedback reduction techniques through perceptual experiments. It is shown that by using a subband NLMS adaptive filtering approach, the same performance of wideband NLMS algorithms is obtained with a fraction of the complexity.