Development of a Miniature Second-order Directional Microphone Diaphragm for Hearing Aids
Dec 2008—Nov 2012
The goal of this effort is to develop a miniature microphone diaphragm for hearing aids that achieves second-order directional sensitivity to sound over the frequency range that is important for speech. A hearing aid that can achieve second-order directional sensitivity can be capable of over 9 dB of attenuation of unwanted sounds that interfere with speech. Existing approaches to achieving this noise reduction are based on the processing of signals from three nondirectional microphones. The effectiveness of these systems has been hampered by the effects of microphone self-noise, and sensitivity to mismatches between the microphones. In addition, the space required to house the three microphones limits the application of these devices to larger behind-the-ear hearing aids. The approach of the proposed study avoids these difficulties by developing a single miniature microphone diaphragm that has the potential of achieving second-order directional response over much of the audible range of frequencies.

This project is sponsored by the National Institutes of Health, National Institute of Deafness & Other Communication Disorders.