4 Replies Latest reply: Nov 4, 2009 3:41 PM by grogsontour
ScuseMe Level 2 (215 points)
Hi all,

I have some rudimentary questions about iTunes, and the "Sound Check" feature in particular.

I've just completed converting my 18K FLAC song library into ALAC, mainly to use iTunes Genius mixes and to be more compatible with my iPhone and Touch. My library was ripped a few years ago when I bought my Sonos system to get whole-house music. At that time, I ripped my CD's into the FLAC to maintain the highest sound quality possible. No equalization was applied during the ripping.

Once I loaded my new ALAC songs into iTunes (converted using XLD), I began experimenting with Sound Check to normalize the volume among my songs, especially where the Genius mixes are concerned (I have quite a bit of classical music). While iTunes started the long conversion of my music to use Sound Check, I started reading about volume normalization and the effects of the quality of the sound. I read that Sound Check was really not the right way to go if I wanted to just normalize the volume; that it also affected the sound quality.

After reading this, I stopped the iTunes Sound Check conversion. Luckily, iTunes had only converted around 400 songs into Sound Check. But now I'm worried about those songs that iTunes did convert, and if I have compromised the sound quality of my ALAC tracks.

How does iTunes determine the Sound Check settings? I initially thought that Sound Check only affected the playback volume of the songs, but upon reading the discussions, it seems to change other things?

Does Sound Check store its parameters in a tag(s)? Or does it physically change the songs themselves? I hope that it does not change the songs, or I'll have to reconvert those 400 songs again.

Is there another program that I can use to just normalize the volume of the songs across my library? In the discussions I read, iVolume was mentioned, but I don't (obviously) have any experience with this program nor any others that affect song playback. Any suggestions as to other apps to investigate would be appreciated.

Thanks for your time.


24" iMac 3.06 GHz Core 2 Duo/1 TB/4 GB/WinXP Pro SP3/VMWare Fusion.., Mac OS X (10.6)