Harvey Fletcher
Harvey Fletcher (September 11, 1884 – July 23, 1981) was an American physicist. Known as the "father of stereophonic sound", he is credited with the invention of the 2-A audiometer and an early electronic hearing aid. He was an investigator into the nature of speech and hearing, and made contributions in acoustics, electrical engineering, speech, medicine, music, atomic physics, sound pictures, and education. Following his death, he was credited with collaborating with his doctoral advisor, Robert Millikan, on the Nobel-prize winning oil drop experiment which first determined the charge of the electron. Provided by Wikipedia
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Published: 1938
Superior document: Bell telephone system B-1067
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Published: 1931
Superior document: Bell telephone system B-568
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Published: 1935
Superior document: Bell telephone system B-896
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Published: 1925
Superior document: Reprint / Bell Telephone Laboratories B-142-1
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Published: 1925
Superior document: Reprint / Bell Telephone Laboratories B-125-1
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Published: 1924
Superior document: Reprint / Western Electric Company, Engineering Department B-79-1
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Published: 1934
Superior document: Bell telephone system B-824
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Published: 1937
Superior document: Bell telephone system B-1015