As you get closer to the music notes, the sound gets louder. This is entirely list-based - the music notes are only there to show you the sound locations - they're not necessary. This also uses fixed "falloffs" that determine how far a sound can be heard from, in pixels.
This can be used for dynamic sounds of objects, in a scrolling game. Yes, this works on both the X and Y axis... Sounds from soundbible.com I'm sorry for the graphics. ;_;