I want to combine two streams using a program called Virtual Audio Cable, and listen to the combined stream, while not making it the DEFAULT sound output device.
Is there a way to listen to an output WITHOUT making it the default one?
This may be what you're looking for: http://downloadsquad.switched.com/2010/06/16/windows-7-tip-how-to-change-the-default-audio-device-with-a-hot/
Well, a little technical info could help, but...
If you go to control panel-> sounds->hardware, click on the device you want to access, and select properties, and disable it (it will disable it, but all references to it as"default" should remain)
Hope that helped