>>Never could get _aplActive to do anything for me.<<

That's funny. My background-sounds routines (called by timer) are all tucked
inside a loop that goes
LONG IF SYSTEM(_aplActive) AND WINDOW(_activeWnd) = 1
<blah, blah> 
END IF
Now that I've got a size resource w/ backgrounding turned off it's
superfluous, but that little loop always achieved its intended purpose: keep
my games from continuing to chirp at me when I step out of the application
into Finder or FB.