Known to all, sound energy is transmitted through the atmosphere in the form of pressure waves. Sound pressure levels (SPL) is expressed in terms of decibels (dB). The frequency of sound is expressed in Hertz (cycles per second).
The overall measurement of sound is converted to an A-scale weighted level (dBA). In order to identify and evaluate an objectionable component of a broad band of sound, the sound pressure levels at various frequencies must be known. To facilitate this, the human sensitive sound spectrum has arbitrarily been divided into eight frequency bands called octaves. These bans have center frequencies of 63, 125, 250, 500, 1000, 2000, 4000 and 8000 Hertz. The instrument utilized to measure the sound pressure levels within these specific bands is known as an Octane Band Analyzer.
To check correct value obtained with the Octave Band Analyzer, it is necessary to develop standards of comparison purposes. For more info, contact cooling tower engineers.
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