I have all my CD's ripped via iTunes to ALAC (~700 CD's 150+GB). I like the library organization iTunes provides and, obviously, it is iPod friendly (my wife has an iPod). I have installed a couple of Squeezebox's in our (nearly) whole house audio system.

I have Slimserver using iTunes as its source for music. I had ripped a few CD's in wma-lossless but then got the iPod, etc. My main gripe now is the vastly differing recording levels between the CD's. It drives me nuts (my wife would say that's no drive, its a short putt). I have read a little about ReplayGain and, after installing FB2K, tried adding replaygain to a few of the CD's I still had in wma-lossless. This does not work as I (and others) found out (some issue apparently unique to wma files).

Finally I arrive at my question. I would like to add replaygain to my music files but, since this is not possible within FB2K, can one convert the ALAC files to, eg, FLAC, add replaygain AND be able to playback via Slimsever/Squeezebox or iTunes (without creating another 150+GB of files)?

Thanks,
Steve

A couple of points:

1. There is a component for foobar which allows playback of alac files: Get it here

2. The problem is that itunes doesn't support other lossless formats "easily". There might be ways to get it to play other formats, but I have no experience on that. However, converting to a format such as Flac or Wavpack which works on the Slimserver is always possible. You can use either foobar (although i'm a bit weary of using foobar because the components page mentions that the alac decoder has some issues)or dbpoweramp to do the job. The free version is sufficient for simple conversion.

3. Itunes has "soundcheck" which is similar to Track gain (or album gain...?) offered by Replaygain. you might consider that if you decide to stick with alac.

Edit: corrected some typos

The Xiph components for QuickTime enable one to use FLAC with iTunes but only if it is in a ogg container rather than in a native container.

http://xiph.org/quicktime/download.html

The latest versions there are 0.1.8 for OS X and 0.1.5 for Windows XP. The versions of iTunes mentioned in the release notes for 0.1.5 and 0.1.7 are now rather old.

http://xiph.org/quicktime/release_notes.html

I've no idea if works currently on either OS. I think the components could be useful if one had some ogg vorbis files but didn't want to install some other player for whatever reason. I wouldn't want to use it for Ogg Flac. Putting a whole library of FLACs in a different container just for this purpose doesn't sound like a good use of one's time to me.

As an alternative to ReplayGain, you could just open up the file and bring the overall volume up permanently. Technically speaking, though, if you do this without dither, there's a small compromise in sound quality. But I think ReplayGain would yield the same results.

Maybe the biggest problem is dealing with songs that are mastered too aggressively -- i.e., with too much dynamic range compression (not data compression). The only thing you can do here is just to keep the overall levels of these songs down so they don't blast you out of the room. In other words, it's better to turn the loud songs down than it is to make the soft songs louder, IMHO.

Note that Apple just patented an auto-level software design, but I'm skeptical of anything that tries to make a "creative judgement" on something like relative loudness.

No, ReplayGain does not alter the data in the file. It only tells the software that plays the file how to raise or lower its volume level.

I'm very much aware of that. I'm suggesting to the user that he or she actually alter the data in the file and change the level permanently. That's a valid alternative to ReplayGain -- provide you have the room to bring the level up, which is not always the case.

Yes, I misunderstood your first post. I thought you were saying that ReplayGain would also compromise sound quality if dither is not used.