What are the best settings for quality AAC encoding? I plan to rip CDs to WAV files with Exact Audio Copy and then use iTunes for encoding. Seems like a good combination from what I've read. But at what settings should I encode files? 128kbps? 192kbps? Or perhaps the outrageous 320kbps? Filesize of lossy files isn't important so long as the quality is excellent. Please let me know what you recommend and use.


Thank you,
Conrad

Personally, I use 192kbps for almost all music, and 224kbps for the music where I want especially good quality - although I probably couldn't ABX 192kbps and 224kbps.

Agree with danchr. 224 is my default, though I can't honestly say I could ABX it with 192 either. I encode up to a manageable size, and for me that's 224.

What is ABX?

http://doc.hydrogenaudio.org/wikis/hydrogenaudio/ABX

I've personally chosen to use iTunes @ 192kbps. This is good for portable usage (ipod), and honestly i can't tell the difference between 192kbps QT AAC and the original Audio CD.

If you're planning on portable usage on a ipod, the smaller the files, the longer the battery will last (generally), since the ipod caches the files in memory before playback, thus it has to read from the hardddrive less often the more music files it can buffer in memory.

I read somewhere that the magic limit for the iPod is 9MB. If a file is less than 9MB, it can be cached completely, otherwise it cannot, and the HD will have to spin up during song playback and thus "waste" battery power.

Why not insert the CD and import directly in iTunes?

With Exact Audio Copy you'll have best chances to get error-free extraction - if errors during extraction have occured you'll be told. This forum (-> FAQ + search engine) contains lots of information related to this.

Yeah, but iTunes got error correction now too.

I have encoded tens of CD's with iTunes and never experienced any errors or artifacts ever.
Also going from WAV -> AAC means that iTunes wont be able to later retrieve CDDB information to the AAC's (which at least is an important feature to me)..

Although I've experienced at least one rip that sounded better with iTunes than EAC (very scratched disk from public library, and iTunes didn't hang up on all of them), it's unlikely that iTunes error correction is as good as EAC. It may be good enough for you and the tag info you mentioned is something to consider in you want to use the QT/iTunes AAC encoder, but with iTunes you really can't be sure you've "never experienced any errors or artifacts ever". The data may not be accurate, though it may not be audible.

I'm going to do the same thing with my cds. I recently ripped them with EAC and LAME --alt-preset standard (mp3). If I import them into iTunes 4.2 and then just convert from mp3 to aac, will I loose quality?

Yes, it will hurt quality. You should rip to WAVs and convert those in iTunes, not MP3->AAC.

Or even better: http://www.hydrogenaudio.org/forums/index....showtopic=12814

I made some interesting experiences with converting MP3 to AAC !!
After encoding Nocturnal Emissions "Mouth Of Babes" with iTunes the background noise from the original recording was radically reduced. First I believed Dolby introduced some kind of Noise Reduction (OK, no big surprised but ...
The same tracks converted from MP3s (lame 3.93.1) contained the original background.

Could it be that a high quality conversion from MP3 to AAC works like some kind of 2-pass and preserves more of the original quality?

No. Whether it preserves more of the original quality isn't all that important. How the audio sounds is.

If you prefer the transcoded files to the raw encodes, it would mean you have a weird taste, but nothing more than that

I really might have a weird taste but ... but my specific samples sound muffled with the original AAC-encoding (iTunes 160 kbps) and near transparacy after transcoding from 256kbps (lame 3.93.1) to 128 kbps (AAC). I can proove it .
Somebody interested in samples?
Ciao

yep,i totally agree with u . i used to encode AAC at 320kbps, and resultantly my iPod ran out within 5 hours. i was wondering why and i knew the bigger file is,the more quickly it ran out. now i am using aac at 192k. i really canno tell the difference,maybe it's because i'm not good at telling.lol

In fact, such statement is required to be backed up with the according samples and/or ABX results.

But I really believe it is your imagination.

What kind of error correction ? If it is plain overlapped reading (often falsely being referred to as "jitter correction"), you won't gain anything with modern drives over plain buffered burst reading.

Not at all. As you stated, the AAC sounds less like the original. It had to drop detail, and the background noise was one of the things to go. In this case, that may not make the result sound too bad, but it certainly isn't anything like the original recording either.

None of us know what kind of error correction iTunes applies. I'd assume that Apple used something that offers a good compromise between speed and ripping quality, but you never know...