I'm looking to get a sound card. Recently I got an Asus DGX and hooked up my headphones through the analog port and speaker system through optical port. The problem I have is that they both run at the same time which I don't want. I want to be able to switch between the sources. I tried contacting Asus and they said it can't do that so is there a sound card which can? I also happened to have a Creative SB0270 to try for fun but it does the samething as well. On board audio can do it so I don't understand why these sound cards couldn't.