FxLMS and Lateralization: A Combined Strategy for Crosstalk Cancellation in Bone Conduction

Abstract

This study aimed to address the issue of "crosstalk" in bone conduction hearing aids, where sound meant for one ear is mistakenly perceived by the other ear via bone conduction. We explored a potential solution by canceling the crosstalk sound at the cochlea. To achieve this, an accelerometer was placed on the mastoid to monitor the crosstalk sound produced by an audiometric bone transducer on the opposite side of the head, while a second transducer on the same side as the accelerometer was used to cancel it out. The filtered-x least mean square (FxLMS) algorithm was used to optimize the crosstalk compensation (CTC) filter for cancellation at the mastoid. Then, the subjects manually adjusted the filter coefficients through a lateralization task to achieve crosstalk cancellation at the cochlea. This task involved modifying phase and level differences between pure-tone sounds from the two transducers, making the sound seem to originate from the leftmost or rightmost side of the head. Our results indicated successful cancellation of crosstalk sound at the cochlea, as subjects' hearing thresholds under noise masking were lower with crosstalk cancellation.