This tool computes the sum of any number of audio sound levels (dB).

Enter the sound levels in dB, each separated by a comma.

## Formula

LTotal = 10*Log10[10L1/10 + 10L2/10 + 10L3/10 … + 10LN/10]

where

• L1, L2, … LN are the dB sound levels of the sources
• LTotal is the total combined sound level in dB

## Example Calculation

The combined sound level from three sources with levels 5 dB, 10 dB and 15 dB is 16.5 dB. This is equivalent to 4.5e-11 Watt.

For a practical example let’s imagine there are three different audio sources: A refrigerator, two people speaking softly and a vacuum cleaner.

The table below provides the sound power levels associated with each

The last row provides the sum (in dB) of the three sources ~70 dB. Essentially, the vacuum cleaner noise will drown out the other two as expected.

Note that sound power level (unlike sound pressure level) does not depend on distance.

## Background

The total sound level is the Log of the linear sum of powers in Watt. The calculator above converts each dB value to a linear equivalent 10L/10. (This is similar to converting a dB value to power ratio).

The next step is to convert back to Log. In other words calculate 10*Log10(Linear sum of powers).

A sound level meter like the one shown below does exactly this in the real world.