Sensitivity to design parameters in an adaptive-beamforming hearing aid

The optimal performance of a two-microphone adaptive-beamforming hearing aid was analyzed under sample conditions. Using a straight-ahead target and a single off-axis jammer, source-to-microphone impulse responses were recorded from head-mounted arrays in anechoic and reverberant environments. Optimal filters (equivalent to the fully converged beamformer´s adaptive filter) and associated system performance were computed for various filter structures and input target-to-jammer ratios. Generally, performance is sensitive to variations in filter length and filter primary-channel delay only under conditions of minimal reverberation and low target-to-jammer ratio. With realistic amounts of either reverberation or target, there is little sensitivity to filter length or primary channel delay