A design for active noise cancellation in the 2cc coupler

Speech recognition in noise environment is always inefficient for hearing-impaired people who wear hearing aids. Many noise cancellations have been proposed and studied for such an issue. In this paper, we designed a prototype of hearing instrument coupler to imitate the equivalent volume of the human ear, and built a feedforward active noise cancellation system (FANCs) that had the algorithm implemented with a digital signal processor (DSP) controller. The hearing instrument coupler is used to study the FANCs efficiency applied to real hearing aids. It is a chamber with an effective volume of 2cc specified by International Electrotechnical Commission (IEC) standard. The FANCs includes a reference microphone, an error microphone, a canceling loudspeaker and a DSP controller. The results show that the hearing instrument coupler could simulate an ear with hearing aid, and the FANCs could suppress the unwanted noise effectively to enhance speech recognition.