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
| Audio Source | Sound Level (dB) |
|---|---|
| Refrigerator | 40 |
| People speaking softly | 30 |
| Vacuum cleaner | 70 |
| Combined Sound Level | 70.0048 |
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.
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