Real-Time Implementation of Unilateral Crosstalk Cancellation Based on Bone Conduction

Abstract

Since a bone conduction (BC) sound can bypass the eardrum and ossicles, BC hearing aids are a great option for those with outer or middle ear problems. However, due to unwanted transmission of BC sound, one of our ears can hear the BC sound that should only be delivered to the other ear, known as the crosstalk sound. Crosstalk cancellation can help with this, although it is unclear how efficient this method would be if implemented in real-time. This paper describes our attempt to implement and evaluate a real-time unilateral crosstalk cancellation system as a solution to suppress crosstalk sound. Since the human head, including its anatomical components, varies from person to person, the system suppresses crosstalk by generating a “user-specific” cancellation sound that destructively interferes with the BC crosstalk sound. It does this by measuring impulse responses (IRs) between bone transducers and a sensor in the ear canal. Then, these IRs are used to estimate a “user-specific” crosstalk compensation (CTC) filter that allows the system to generate the cancellation sound. We implemented the system on the Bela Mini embedded audio platform and achieved a latency of 1.65 ms. We tested the system on eight normal-hearing participants and confirmed the reduction in crosstalk sounds at the sensor location.