Wouldn't it be cool if someone who knew what they were doing (presumably many of you) created a plugin for itunes that created a soundcheck tag that was calculated by album and not by individual song?

People already developped this and it's called ReplayGain.

Too bad Apple doesn't have a clue - and doesn't support it.

You may want to check out the foo_pod thread & then contact the authors.

I believe they've already mastered soundcheck.

Hopefully this will at least get you closer, tec

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haha Garf.

We mastered SoundCheck (which we can call "ReplayCheck" now, if you like ), but only with regards to the iPod. We still don't know how to insert a tag into a file that iTunes will recognize and use.

Essentially, for MP3's (dunno about M4A's) iTunes puts a field in the comments in the tag that looks like "iTunNORM 0000abcd 0000abcd ..." with a bunch of hex stuff following it.

What we discovered was that:
a) The first hex chunk is the volume adjustment expressed in microWatts (iTunes itself shows it in dB).
b) It puts this value in a certain place in the iPod's database.

So now foo_pod will take ReplayGain values, convert them from dB into microWatts, and put that in the proper place on the iPod. So the iPod's SoundCheck function now will use ReplayGain values when you have it turned on. It works.

But that's all we found. The rest of the crud in that iTunNORM comment is still unknown. So we can't create a comment similar to that, and in any case iTunes ignores that comment at all times *except* when you initially add the file to the iTunes library.

If you want to add your files to iTunes to get the comment to be added, then remove the files from iTunes, then calculate the ReplayGain values, then convert them to microWatts, then edit the comment in the M4A files to change that value, then add them back to iTunes, it'd probably work. Maybe. Dunno, I haven't tried it.