Amplifier - dB Calculation

There are two important dB calculation for amplifier output.

1. How many dB SPL between two wattage levels.
2. The difference in watts that need to be achieved for a given change in dB SPL.

WATTS TO dB ( Watts to SPL):

You want to change a 100W amplifier to 350W amplifier. How many more dB you can get out of your loudspeaker?

Answer : dB = 10 x log ( watts 2 / watts 1) or 10 log ( 350/100) = 5.4 dB