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Sound Intensity |
The sound energy transmitted per unit time through a unit area, thereby being a measure of the magnitude of a sound. The unit of measurement is the erg per second per square centimeter, or the watt per square meter. The threshold of Hearing lies at 10-12 watts/m2, whereas the threshold of pain is about 1 watt/m2.
The measurement of sound intensity is its intensity level and is measured logarithmically in decibels because of the wide range of intensities involved. See Appendix D for the conversion of intensity ratios to decibels.
Sound intensity is proportional to the square of the sound pressure, which, being easier to measure, is more commonly used as a basis of sound measurement. Sound intensity in free field situations varies inversely as the square of the distance from the sound source (see inverse-square law).
See: Noise Level, Sound Level, Sound Pressure Level, Sound Wave. Compare: Amplitude, Loudness, Power, Volume, VU Meter.