I've got a setup similar to what you're looking for, except I use Mumble instead of Vent or Teamspeak when gaming. The key is that I have a discrete sound card (like you). I use the onboard Crab audio for headset out (Mumble audio only) to my Razer Carcharias, X-Fi mic for audio in from the headset and X-Fi 5.1 analog out to my Z-5300e's for my surround sound. I didn't even need to install the drivers for the onboard - though you may need to make sure it isn't disabled via BIOS.
Since I don't use them, I suppose the only thing you need to worry about is whether or not Vent or Teamspeak allow you to change your I/O devices or if it only allows you to output/input to/from your default devices.
just brew it! wrote:A bigger concern is feedback. If the sound is coming out the speakers and the mic is on, you may have some feedback issues...
Not really an issue with this set up since the voice is headset only and the mic usually doesn't pick it up. You may need to turn down the mic sensitivity or turn up the cut off volume since it may pick up game/music audio coming from the external speakers or your gaming buddies may sometimes complain of hearing an echo.
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