Phonometer
1. Phonometer is an instrument for measuring the intensity of sound or the frequency of its vibration.
2. A phonometer is an instrument invented by Thomas Edison for testing the force of the human voice in speaking.
Phonometer 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.
Phonometer works on the principle of comparing the volume of noise with the volume of standard sound supplied by the device. Phonometers with a volume level of 90… 120 dB and different intensity of sound volume drop are available.
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