iVolume
Description
I am sure you know the problem: Especially when listening to your iTunes- songs in shuffle-mode, you will notice the differences between the volume level on every song. With iVolume it is easy to adjust all songs of your iTunes- Collection to the same volume level.
But iVolume is not just performing a simple peak analysis. Instead, iVolume uses algorithms to adjust volume levels to the same "perceived loudness". The results are much better than iTunes' built-in "Sound Check" function.
Remarks
iVolume is written by Manfred Lippert. I am doing of beta- tests since late 2003.