Noise reduction for hearing aids: Combining directional microphones with an adaptive beamformer

Abstract

Many hearing aid users complain about a reduced intelligibility of speech in noisy environments. Directional systems are a successful approach for noise reductions in hearing aids. These systems transmit signals from acoustic sources lying in front of the hearing aid user while suppressing signals from other directions, which are assumed to be noise. Several methods are known to obtain directivity. One is to use directional microphones, another is digital postprocessing of several microphone signals. In this letter, the combination of directional microphones with the adaptive beamformer, a directional signal processing approach, is discussed. Intelligibility tests with both normal‐hearing and hearing‐impaired subjects are presented. It is shown that the combination of directional microphones with digital postprocessing is able to improve the intelligibility of speech in a noisy environment significantly, when compared to any one of these two approaches by itself.