A Miniature Ceramic Microphone
Mead C. Killion · The Journal of the Acoustical Society of America · 1971
The traditional goal of the hearing aid transducer designer has been the maximization of speech perception under adverse conditions. The resulting transducers have thus had a frequency response extending from roughly 300 to 4000 Hz, falling off rapidly above and below those frequencies. An alternate goal—a more “natural” sound—necessitated a new approach. A ceramic microphone with a built-in FET preamplifier was designed to occupy only 0.006 cu in. and yet have a wide smooth frequency response. Studies made on an electrical analog of the microphone verified the availability of several potentially useful frequency responses. The actual shape of the final frequency response was dictated by head and ear diffraction studies, amplifier considerations, and listening tests.