Since you have sound going, look around in the outliner see if there isn't a node in there for the sound.. I haven't played with sound yet.. but its possible there is a node already in your seen since you got the sound in for animation. If you find a node in your outliner for the sound on the animation.. there is a chance you can find a volume attribute off it that you can plug in to something else. Like say a multiply / divide node wired on in to the emissions property of the particles.