Aaaaaaaaah, now I get it.
OK, there is a way to set this up under Windows XP, I haven't found anything in Vista yet, although I've been activaly looking for it for 8 months, ans I can't speak for Linux etc. (chances are you're not running this Aspect thingamajig on Linux, am I right?)
Control Panel>Sounds and Audio Devices>Hardware tab>Properties>Properties tab(redundant but true)>Mixer Devices>Select sub-branch>Click on Properties(trust me)>Select "Do not use mixer features on this device".
This will cause the foreground application to monopolize your hardware and cut off whatever else is generating sound on the PC. I think we've got it now. Pls test and confirm that it works for ye.