Using linearly-constrained adaptive beamforming to reduce interference in hearing aids from competing talkers in reverberant rooms

Adaptive beamforming techniques can be applied to the problem of reducing interference in monaural hearing aids from sound sources that are spatially separated from a target source. We implemented a two-microphone Griffiths-Jim [1] beamformer in simulated reverberant environments (anechoic space, living room, and conference room) in which target sentences originated straight-ahead of the array and interfering speech babble originated 45° off-axis. We evaluated the system with intelligibility tests administered to normal-hearing subjects. Compared to listening through a single microphone, the two-microphone beamformer reduced the target-to-interference ratio required for 50% keyword intelligibility by 30, 14, and 0 dB in the anechoic, living-room, and conference-room conditions, respectively.