MP3, WAV,AAC,Audible,AIFF,Apple Lossless

Any lossless format - typically Apple Lossless and EAC - and any uncompressed format - ie .wav and .aiff will out perform anything but the best CD player. Two parts to the magic - first as you already surmised is the way the rip is done. But of equal importance is the decrease in jitter and other artifacts that comes when you use a hard drive as a transport instead of a CD player. Third piece of the mystery is to get the data off the hard drive using USB, Firewire, Ethernet or Toslink on certain Macs as opposed to using a soundcard and SPDIF

AAC and MP3 can be very good depending on the compression selected but are mostly used in portable devices where file size is an issue.

This isn't something I'm an expert about but since you haven't gotten any other responses I'll try to help.

The acronyms in your list aren't all compression systems. In fact the only two that do involve compression are MP3 and Audible.

In a nutshell, WAV, AAC, AIFF and Apple Lossless are audio file formats that are used for either storage or transmission and all preserve the original sound you'll get from a CD. There are those who are suspicious whether the Apple Lossless format really is lossless but I'm not oone of them. Which format you encounter will depend on who created the original file or which you choose to convert to in storing or playing your own files.

MP3 is a compression scheme that throws away some data in the interest of smaller storage or download time. How close it remains to CD quality depends on the 'bit rate' of the MP3 compression but the quality always suffers somewhat relative to the original file.

Audible is simply a proprietary 'wrapper' for MP3 files distributed by audible.com and it has the same quality constraints as MP3 files since the audio data is, in fact, in an MP3 file.

A correction to my earlier post, AAC is a 'lossy' format which does use compression but is claimed to be higher quality than MP3 for equivalent file size. It's the format the tunes from the iTunes Music Store come in. Sorry about that.

Minor points, but... Ckorody--you said EAC and I think you prolly meant something else; EAC is a CD ripper that can be configured to produce nearly any format audio, whether ALAC, AAC, WAV, MP3, FLAC, etc. Sfar, but Apple Lossless *is* a compression scheme, its just that its a lossless (v. lossy compression scheme).

AIFF and WAV are simply file packages for raw PCM data. They are uncompressed and functionally identical.

WMA Lossless, Apple Lossless, and FLAC are examples of compression schemes that make file size smaller, but in a way that is reversible with no information loss. Typically, it means less compression savings, but no lost data. (Like "zipping" a computer file).

MP3 and AAC are lossy compression schemes. They sacrifice data for greater compression. They typically use psychoacoustic algorithms to decide what can be lost from the file with minimal impact on acoustics. Since MP3 and AAC are lossy schemes, they typically have parameters that can be varied (e.g., bit rate) that implicate more or less compression and, conversely, less or more data loss and audible impact. So, two mp3s of the same song may not sound alike--a VBR mp3 is a lot better sounding than a 128kpbs CBR mp3 in most cases.

So, makes no difference if you use AIFF or WAV. Next best (I would argue identical) would be ALAC, FLAC, or WMA Lossless. Next best is variable bit rate MP3, or high bitrate AAC. For a given bitrate, I also recall the pundits preferring AAC over MP3.

Using a decent playback system--i.e., good outboard USB audio device--any lossless format will compare favorably with very high quality CD transports.

Thanks, Gentlemen!

The information you've provided is very helpful.

Regards,
Troy Scott