Is it humanly possible to make the music sunc with the game, so that if the FPS of the game goes down, the music will slow down and wait for it. I know by default this isn't possible, but is there a way to change this?

Maybe with a dll...You'd have to code or get someone else to code something outside of game maker, OR, if you wanna risk lag, make game maker "make" the music via soundeffects and programming.

yeah lags not an option in my situation. Maybe I'll ask around the official forums for some dll help. thanks!