MP3

Ok I only know the basics here but this basicly what an MP3 is:
An MP3 differs from a Cd or a Wav file in the fact that an mp3 has less "sound" so to speak.The file,when its encoded it does not record sounds that people can normaly hear.That is whydepending on the qulity of the mp3s you can fit more on a cd.An MP3 is also encoded difrantly to a cd/Wav and that is why it wont play on a normal cd player.
Which is why if you what it to play on a normal system you must decode the MP3 back to Wavand cut to CD .

There are variour mp3 player and recordes on the market.Some of the better recorders give you the option to record your mp3s at different quaities.I try record my own mp3s if posiable and record them at 128k or 196k any thing delow and you lose quality ,the low quality is not realy noticeable on smaller speakers(ie Your PC) or headphones,but if played on large sound systems you can hear the diffrance the music sound "flat".The better the MP3 quality the larger the file.

Agood example is a friend of fine had a mp3 that he wanted on cd to play in his cd the mp3 sounded fine when played on the pc but once conveted to WAV it was scratchy and basicly sounded like a poor recording for radio.

So to sum up the difrance in an MP3 and a normal audio file is what you dont hear and whe way the file is encoded.