Loudness, or sound intensity level, is a human perceived or subjective measurement with units, decibels, based on the response of the human ear to different sound intensities. The response of the human ear at fixed frequency is close to being logarithmic.1,2 The experiment reported here investigates the relationship between measured sound intensity level, or loudness, and distance from a sound source such as a loudspeaker.

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Neal P.
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Richard P.
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4.
The PASCO Sound Level Sensor, product code PS-2109. PASCO scientific, 10101 Foothills Blvd., Roseville, CA 95747-7100; http://pasco.com.
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