Head-Contact Microphone for Efficient Speech Transmission
A. Rosenheck, A. DiMattia, Benjamin B. Bauer · The Journal of the Acoustical Society of America · 1966
Work was undertaken to develop a microphone that would provide highly intelligible speech reception by direct contact with the head. Since investigation (Paper 7D4) showed that the forehead provided the bighest quality speech, efforts were concentrated in this region. In order to avoid a loss of high-frequency response owing to flesh compliance, the total mass of the transducer had to be limited to below 1 g for a unit of small size. This was most readily accomplished with a miniature, inertial-type transducer, which, additionally, provides the proper response-frequency characteristics. Articulation tests, with the microphone located on the forehead, indicated an average PB word score of 90% in quiet surroundings. Good rejection of ambient acoustical noise was observed. The ultimate noise rejection is limited by noise-induced vibrations transmitted through the head. The microphone totally frees the mouth area of obstacles located in front of the lips, and its miniature size suggests several applications. [Work supported by the U. S. Army Electronics Command.]