Signedplate on back of mouthpiece: Western Electric / REG. U.S. PAT. / 618 A NO 1003
on plate: PATENT / 1373019 1456538 / 1692317 1707544 1766473 / 1847702 PAT PEND / MADE IN U.S.A.
FunctionThis microphone was used for all sound measurements from about 1935-6 to 1943, including PAL's voice articulation experiments from 1940 to 1943.
Historical AttributesThis microphone was used in the Psycho-Acoustic Laboratory in Memorial Hall for all sound measurements from about 1935-6 to 1943, including PAL's voice articulation experiments from 1940 to 1943.