Decibel Adder
Add two sound levels on a logarithmic scale. Two equal sources are about 3 dB more, not twice as loud.
Frequently asked questions
Why not add the numbers?
Decibels are logarithmic. 85 dB plus 85 dB is about 88 dB, not 170.
Does a 10 dB gap matter?
The louder source dominates. A source 10 dB quieter adds only a fraction of a decibel.