Phonometer
Appearance
Aphonometeris an instrument invented byThomas Edisonfor testing the force of the human voice in speaking. It consists chiefly of amouthpieceanddiaphragm.Behind the diaphragm is placed a delicate mechanism which operates a 15-inchflywheelby means of which a hole can be bored in an ordinary pine board.
References
[edit]- This article incorporates text from a publication now in thepublic domain:Beach, Chandler B., ed. (1914). . .Chicago: F. E. Compton and Co.
External links
[edit]The dictionary definition ofphonometerat Wiktionary