I'm not quite sure, winamp has covered the file extensions so i'm not sure. Each file is about 40mb (CD ones) I also have Mp3's of about 5mbs. As long as either one of these units is good for what i'm doing, I think I'll proboly buy the higher model b/c I read it has more battery life and also, it looks better . For now, I have some mics that I got from radioshak, but if I remember, they were very high quality ones (definenlty over 50$). My brother bought them to use for our 4track digital recorder. Also, upon further research, I read that the sony software is HORRIBLE. Does it have any limits on how many times you can erase and put on new files on a MD?