I've never used it, but MP3Gain is designed for this kind of stuff. Check it out at http://mp3gain.sourceforge.net/index.php
Got a question maybe someone has an answer to. I currently have about 6Gb of music in Mp3 format on my hard drive. Upon hooking it up to my sound system in my car during testing, i noticed some songs are louder than others, probably because of the volume level it was ripped at. All my music has come from different sources, and was ripped at different times, and therefore has different volume levels. What can I do to normalize the volume of my entire collection? Is there a program that can do this? Or will I have to manually take each album, and re-rip it using DBpoweramp or something. Thank you.
Check out Volume Logic. I use it and it's awesome. They have versions for all the major media players.
The program will start with your music player and has several pre-defined settings for different genres. It will automatically level the volume, gain, highs and lows of the songs you play - in real time.
...built into iTunes...cough cough OSX rox...cough
iPad Mini 128GB, RF 600.5 amp, JL12W0V2, 8 Infinity Components