Adding & averaging decibel values

Adding or averaging decibel values seems like a closed book. But the calculation with these hacks shown here is very easy to do with a calculator or in your head.

In words:
Addtion of 2 decibel values:

* Divide the decibel values by 10.
* Then calculate 10 to the power of this number - then add them together.
Now back to the logarithmic system:
* Calculate the log of the sum. Now we have "Bel"
* Multiply the result by 10 and we get the deci-Bel value .


Average of decibel values: Minute: 4:44
The same as Addition, but before you the log you first have to divide the summation of all summands by the number of summands. (This is the way you calculate an average in any case)




This is part 3 of a decibel explaining series.
Links to the other tutorials of this series:

Part 1 - Why decibels in acoustics - Acoustics Basics (Recommended)
Why decibels in acoustics - Acoustics...

Part 2 - Handling decibel values with ease
Handling decibel values with ease

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Part 4 Working with decibels - Analysis Software
Working with decibels - Analysis Soft...