Feedback cancellation in hearing aids: results from using frequency-domain adaptive filters

Feedback, both acoustic and mechanical, is a common complaint of hearing aid users. As an alternative to conventional LMS (least mean square) predictors the authors have investigated the use of frequency-domain predictors, which are based on the so-called “overlap-save” technique. In contrast to previously proposed frequency-domain schemes, the authors´ predictor converges to the Wiener solution. It allows at least a 20 dB increase of the critical gain of a BTE (behind the ear) hearing aid device without noticeable distortion of a speech signal. Together with the loss-compensating forward filter the proposed scheme can be implemented very efficiently