Do any of you guys use replaygain with Classical music? I've noticed that the dynamic range makes it sometimes hard to hear the quiet parts.
Yes, I use Replay Gain for classical music. It is correct that Replay Gain does not change the dynamic range within a track. What it does is change the volume of one track vs. another or one album vs. another depending on whether one is using track Replay Gain or album Replay Gain.
I think a lot of folks become confused because there are two different types of Replay Gain. Track Replay Gain and Album Replay Gain.
Track replay gain changes the volume of one track vs. another. Album replay gain changes the volume of one album vs. another while still preserving the differences in volume between tracks within each album. Neither one changes the dynamic range within a track.
Clipping can result. It gets a little complicated, because it depends which implementation method you're using, what type of file you're talking about, what music player you're using, how much the particular file is being corrected, etc. etc. Here's a pretty good article:
I use foobar2000 and so far I've only applied ReplayGain to MP3 files. I haven't been able to detect any audible clipping in my use of it so far, but your mileage may vary.
They might know more about it over in the Sound Science forum.