View source for Technical Information on Replay Gain Adjustment

Here's a summary of the process: 

For Each File: 
# Figure out how much we could safely turn a file up using the peak level.
# Use (1) to see how much we could safely add to the replay gain level 

Auto preamp will be the minimum (2) from all the files.

==Example with 2 files ==

A: peak level: 50%, replay gain: -10 dB <br>
B: peak level: 75%, replay gain: -4 dB <br>

A(1) = 50% -> +6dB could be added safely <br>
A(2) = +6dB - -10dB = 16 dB could be added to RG <br>

B(1) = 75% -> +3dB could be added safely <br>
B(2) = +3dB - -4dB = 7 dB could be added to RG <br>

Auto preamp = min(A(2), B(2)) = +7 dB 

During playback: 

Actual gain (A) = -10 dB + 7 dB = -3 dB <br>
Actual gain (B) = -4 dB + 7 dB = +3 dB