Signedon instrument: Sound Analyzer / Type 760-A Serial No. 311 / General Radio Co. / Cambridge, Mass. U.S.A.
[similar signature on top of cover]
Inscribedon instrument: 76-B-576 / Tr-HU-2/7/61
on instrument, plaque: P.A.L. Serial No. 33
on instrument, stenciled: ANON. RESEARCH / S.S. STEVENS [also on the inside and top of cover]
plaque on cover: This instrument is licensed, under Patents of / the American Telephone and Telegraph Company / solely for utilization in research, / investigations, measurement, testing, / instruction and development work / in pure and applied science.
Historical AttributesBetween 1940 and 1945, Harvard physicists and psychologists worked side-by-side to bring man and machine into a harmonious union. Communication equipment studied and engineered by the Electro-Acoustic Laboratory was sent to the Psycho-Acoustic Laboratory for speech articulation tests with human subjects in high-noise or low-pressure environments. Leo Beranek's and Stanley Stevens's teams developed improved microphones and earphones, and the armed forces rushed these into production.
This instrument was designed to work with the type 759-A sound level meter, although it could be used with any other microphone and amplifier having similar characteristics. It not only measured the amplitude of sounds, but also its frequency range.
Primary SourcesJ. D. Cobine and J. R. Curry, "Range Extender for General Radio 760A Sound Analyzer," Review of Scientific Instruments 17 (1946): 190-194.
Related Workshttps://www.radiomuseum.org/r/gener_raco_sound_analyzer_760_a.html