I just found out this little tid bit of info I thought I would share with you concerning mp3 files:
Q: How does MP3 audio quality compare to CD?
A: A well-encoded MP3 file has what is called "near-CD" audio quality. Like the ATRAC compression used in MiniDisc recording, MP3 reduces file size by selectively removing information that is beyond the frequency range of human hearing or that is "masked" by more prominent sounds that occur simultaneously. Music compressed with MP3 at good quality (128 kb/s) requires 10 times less memory than it would in the uncompressed CD format. That means downloads are 10 times faster and MP3 players can hold 10 times as much music in the same amount of memory space. When compared side-by-side with the original CD, an MP3 file sounds very good, and for many pieces of music the sound quality will approach or be perceptively equal to the original CD recording.