128kbps AAC, which isn't too good
Bitrate is a poor indication of what the decompressed file is going to sound like
mp3 is mpeg-1 layer 3
AAC generation 1 is mpeg-2 layer 7, and AAC generation 2 is mpeg-4, both of which are FAR better compression than mpeg-1
And the quality of the encoding process itself has a LOT to do with how good the finished file sounds.
Take, for example, mpeg-2 harware compression, which can be used to record a file from a video capture card directly to your hard drive, or a dvd (standalone dvd recorder) in real time.
It's GOOD quality, but when you compare it to a commercial grade professionally digitized dvd you'd buy at the store, there's no comparison. The encoding process alone used to create commercial dvd's takes WEEKS to complete.
The same difference in final quality can be attributed to using the 'fast' 'typical' and 'slow' encoding settings in LAMEmp3, WMP, or any encoding program.
The more passes you allow the encoder to take, the more data it can keep, and squeeze into your selected bitrate, while a faster encoding process doesn't go back and recheck to optimize your bandwidth, and often times throws away data that it didn't need to in favor of getting done faster.
So a 128kbps AAC file you make at home, and a 128kbps AAC file you download off of itunes, while both being LIGHTYEARS ahead of mpeg-1 layer 3, could potentially sound quite different from each other.
And to the original poster, 0db white noise is often added to copyrighted tracks that are shared illegally on p2p programs, by the anti-piracy teams creating identically sized/named/and tagged files as the songs they're attempting to protect, which are not the song itself, but nothing but white noise.
By putting these 'fake' files on a super fast T1 or T3 server, your p2p program often switches to their servers if your primary source drops in speed, or kicks you off, leaving gaps and parts of the song as the 0db static rather than the main song, so it's in the source itself, it's not a product of the recording process.