sound interaction depending on mouse position

Hi!

I wanted to do a project with a movie constantly looping and sound changes depending on the mouse position.

I have four different songs. What I want is to have the mouse position effect the sound. For example when you move closer to one corner, the sound that is connected to that corner has a higher volume so the sound blend together when your mouse is more in the middle. In the middle of the screen it would be completely quiet. How can I do this?

thanks
/Emma