Just went out and bought a set of Logitech X-540 Speakers.  I have an older SB Audigy sound card (4 channel).  
The speakers come with a "matrix" button that is supposed to blend the front right and front left speakers together for the center speaker to output, but it doesn't do anything for Aces High.  
When I have the button pushed in, it works for Red Orchestra, Team Fortress 2, and Civ 4... but no sound comes out of it in AH.  
Can anyone think of a reason why it might be happening?  I have the speakers set up as 5.1 speakers in the Windows sound config and under Creatives little config thing.