Sound power level - Definition and Overview

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 "L_w" 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).