Phonometer
Appearance
A phonometer is an instrument invented by Thomas Edison for testing the force of the human voice in speaking. It consists chiefly of a mouthpiece and diaphragm. Behind the diaphragm is placed a delicate mechanism which operates a 15-inch flywheel by means of which a hole can be bored in an ordinary pine board.
References
[edit]- This article incorporates text from a publication now in the public domain: Beach, Chandler B., ed. (1914). . . Chicago: F. E. Compton and Co.
External links
[edit]- The dictionary definition of phonometer at Wiktionary