Sound power level
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Sound power level or acoustic power level is a logarithmic measure of the sound power in comparison to the reference level of 0 dB (decibels).
The measure of a ratio of two sound powers is
- <math>
L_W=10\, \log_{10}\left(\frac{W_1}{W_0}\right)dB <math>
where W1 and W0 are the powers.
The sound power level is given the letter "Lw" or SWL and is measured in "dBW". dB is dimensionless.
If W0 is the standard reference sound power, where
- <math>W_0=10^{-12} {W}<math>
(W = watt), then instead of "dB" we use "dB SWL". (SWL = sound power level).
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