text: i'm confused.  if a cd-r is 700mb and the average four minute song is 4mb, why does the cd record only 80 min? seriously, this shouldn't be so complicated.  will my car sound system play mp3's? there are different formats for cd, like cd-audio, vcd, svcd etc, each format has its own way to store data. if we are talking about cd-audio standards then it can store upto 80 minutes of sound recording, this will be stored on tracks, you can not store these tracks to your computer hard disk. if you want to store your audio cd on your computer then you have to convert it (rip) into mp3 or wma format using media player 10 or any other ripper, it will convert the cd-audio track into almost 4mb file. but remember its another standard. the best way to check whether your car sound system play mp3 or not is that try to play an mp3 cd in it. :)