700MB CD can't hold 80 minutes of music?

[Blue Dolphins]

When I try to burn a CD, about 70 minutes of music takes up 700mb, but on the CD it says 700mb, 80 minutes, and I know that purchased CD's can hold 80 minutes too, where's that extra 10 minutes? Is there someway I can get ahold of those 10 minutes, they're the often the difference between being able to fit 2 albums on one disc and not being able to.

[lswb]

Are you creating the CD as an audio or music cd, or as an ISO? If the latter, there will be filesystem information and other overhead not found on a music only cd, so the total playtime would be somewhat less. Check the settings of your burning program and make sure it is creating a music CD and not some type of data CD that happens to contain music.

[Blue Dolphins]

I'm burning it as an audio CD, with brasero.