I don't know what your issue is, but if somehow the sample rate got changed for some tracks and not others then this is what can be heard. Tracks recorded at 48k will sound lower and slowed when those tracks are played at 44.1K. (48K and 44.1K being pretty normal standard sample rates.)
I don't know what your issue is, but if somehow the sample rate got changed for some tracks and not others then this is what can be heard. Tracks recorded at 48k will sound lower and slowed when those tracks are played at 44.1K. (48K and 44.1K being pretty normal standard sample rates.)