A power measurement lik the dBm but referenced to 1 W. The dBW is gererally too large a measure for microphone and line level audio but may be used to quantify the output of a power amplifier.
0 dBW = 1 W +16 dBW = 39.81 W
The dBW is related to the dBm by: dBW = dBm – 30
