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**

**L _{Total} = 10*Log_{10}[10^{L1/10} + 10^{L2/10} + 10^{L3/10} … + 10^{LN/10}]**

where

**L1, L2, … LN**are the dB sound levels of the sources**L**is the total combined sound level in dB_{Total}

**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 **10 ^{L/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*Log _{10}(Linear sum of powers)**.

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

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