The issue is the very beginning audio track for the intro starts half way through.
Do you mean
stops halfway through?
It sounds like your lens is starting to go bad. I had similar problems with a Duo but didn't think it was my lens because I only experienced the problem with some games and not others. It also usually happened on intro tracks or music for the first level of a game.
Before you buy a new lens, try using a lens cleaner CD. After that, get a screw bit, open up your console, and put a couple drops of oil on the spindle, metal rods, gears and other moving parts. If that doesn't do it, try giving the white potentiometer a quarter turn one way or the other. These techniques have solved some other problems I've encountered but I believe you have a lens issue.