GregB

Just for giggles, I launched CoH in XP SP3 compatibility mode, and was allowed to enable 3D sound. It seemed to be working correctly as well. Give that a try.

The Xonar D2X (which I have) also has a driver-based solution for running DS3D games in Vista/7, which worked well enough in City of Heroes, but I cannot enable the option in-game anymore.