04251686 is referenced by 25 patents and cites 9 patents.

A closed sound delivery system includes a sound generating unit coupled to provide sound to an ear in response to electrical input signals and an electrically equalized sound receiving unit coupled to accurately receive acoustical signals provided by the sound generating unit in the vicinity of an ear. The delivery system provides a pressure at the eardrum with a frequency response which remains flat up to about 30 KHz. The sound generating unit includes a low acoustical output impedance transducer and a suppressor element which attenuates acoustical energy emanating from all but a small central region of the transducer to minimize frequency response variations resulting from constructive and destructive interference of acoustical energy originating at different physical positions. The receiving unit has a 6 dB per octave high frequency roll off due to the characteristics of its terminating elements while an electrical high pass filter compensates for this roll off.

Title
Closed sound delivery system
Application Number
5/965482
Publication Number
4251686
Application Date
December 1, 1978
Publication Date
February 17, 1981
Inventor
William G Sokolich
5309 Victoria Ave., Los Angeles, 90043
CA, US
Agent
Fraser and Bogucki
IPC
A61B 5/12
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