Like almost any application, when you minimize Demigod the music and normal sound effects fade out.
I just stumbled across something that scared the shit out of me and subsequently made me laugh my ass off.
I have been playing around with FRAPS and a couple of other video capture options today. This has lead to me Alt-Tabbing out and messing around with settings and watching recordings while Demigod is playing in the background.
I tabbed out of the game to watch a replay of a kill I had just made against a silly normal AI. I turned up my system volume to compensate for the fact that I was capturing at a low volume when I made the recording. As soon as the clip ended I was nearly jolted out of my seat by a BOOMING bass pounding through my headset---- WWWWWRATHFUL!
I had parked my Rook at the crystal without pausing the game. One of my allies made a kill. Apparently the voiceover doesn't get supressed when you minimize the game.