Or something...

Basically I recorded a gig live with my iRiver for a mate, using headphones as mics and he recorded it off the desk with his MD.

So as neither's really very good I wanted to combine them but bizarrely my copy from the MD recorded into the computer is a different length to the one my iRiver took. I've overlapped them and no matter where I get them to overlay perfectly, later on in the gig it's totally screwed. I'd expect this from cassettes but not from two digital recordings.

Now in the past I've used this but I recorded both with MD.

I'm really confused how there could be this disparity.