are you asking the difference between burning mp3's as data as opposed to audio??? if so, the differences are: 1. burning as audio allows the music to played on the home stereo or car stereo. You are only allowed 80 minutes of audio on a 80min cdr 2. burning as mp3 allows you to play it on equipment that can read mp3 files as audio. This way you can get around 10hrs of mp3 music on 1 cd.