Concurrent Acoustical Feedback and Occlusion-Effect Cancellation in Hearing Aids: A Simulation-Based Analysis

Abstract

Occlusion-effect and acoustic feedback are common complaints of the hearing aid user. The occlusion effect is described as an annoying quality of the user’s own voice that sounds hollow or boomy, while feedback instability results in an unpleasant loud continuous tone. Despite the availability of high performance feedback cancellers, severe to profound losses require large amplification and, as a result, certain degree of occlusion to minimize feedback. The smaller the vent, the greater is the feedback-path magnitude attenuation as well as the increase in the occlusion effect. This work presents a numerical simulation investigation about the concurrent use of the prediction-error-method feedback canceller and the feedforward-occlusion canceller in hearing aid applications. Evidences about mutual performance impact on both cancellers are pursued. The studied scenario takes into consideration three sizes of the ventilation opening of the hearing aids. Simulation results indicate that the individual performance of both cancellers is not affected when the stability is preserved. This finding can be of interest for hearing aid designers when setting up the canceller parameters.