Phonometer

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

• This article incorporates text from a publication now in thepublic domain:Beach, Chandler B., ed. (1914)."Phonometer".The New Student's Reference Work.Chicago: F. E. Compton and Co.

External links

• The dictionary definition ofphonometerat Wiktionary