Hey guys,

I currently have all my music in AAC , 192 kbps and 128 kbps music from the iTunes Music Store. Is this an acceptable quality? I have notice, some problems with the lows, though it is much better than my mp3s at 160 kbps. I am thinking about redoing my CD collection to AAC 256kbps, I will even go up to 320kbps if you guys can somehow convince me. I do not have ALOT of music and I have PLENTY of room left on my Mac and my 15Gb iPod.

What is an acceptable bit rate that allows the person to "not notice" any differences (of course you will with the compression, but you know what I mean) and acceptable for use with an iPod.

-Phong

The general consensus is that MP3 at higher bitrates is better than AAC at higher bitrates. At lower bitrates, however, AAC is far superior to MP3. Have you tried LAME. I have most of my music encoded at ALT+Preset+Insane, and couldnt be happier. I hope this helps.
BTW I think this is my 200th post

I'd say 256kbps should be the max. After that, you won't be able to hear any difference at all. I don't even think it would matter to go above 192. Converting them probably won't make a difference for you.

I haven't done tests in this respect and am repeating things I've read mostly on Hydrogren Audio, but a few people are calling AAC (as it's currently tuned in QT) best at 192kps and anything above "academic", etc. So in that sense 192 is probably as good as it's going to get with AAC currently (problems at 192 are problems with the compression format itself, MP3 has its own limit). And as mentioned 160, 128, ... is better with AAC, then CBR MP3 160, 128... As 192 is approached you enter LAME preset standard and preset extreme MP3 territory with dramatic VBR advantages and here generally it seems most agree MP3 retakes the quality lead. Again we're just taking these two formats (there are many others- though not for your iPod) and just the best encoders of each (LAME and QuickTime), so there can be exceptions to these rules. Hope this helps. For the record, I encode everything at "--alt-preset fast extreme --vcomment" with LAME 3.92. Find it's the best size/quality compromise.

For the Mac I find the LAME-iTunes prog/script here very useful.

EDIT: If you really want to stick to AAC check out AACelerator to encode using a higher setting in QT, than iTunes uses (which doesn't use BEST or BETTER but GOOD because of speed).