Originally Posted by ProtegeManiac
If you just want to get surround sound for most games, just use the analog outputs on the motherboard and hook that up to a bundled surround multimedia speaker system - Logitech, etc. Then use either the digital output or USB to a DAC with a headphone amplifier for better quality 2ch audio.
That would mean no CMSS-3D Headphone or Dolby Headphone, though (barring a select few motherboards like Gigabyte's G1 line). That means one-dimensional left-to-right panning in games, with no sense of front and rear whatsoever, since that's how games mix pure stereo for headphones.
Needless to say, if you want that sense of surround out of the headphones and not speakers, that setup isn't going to work out unless you replace the motherboard sound codec with a dedicated sound card, or the only games you play happen to all use OpenAL (which is very, VERY unlikely) so that you can just use Rapture3D on all of them.
Also, there are EAX reverb/chorus/occlusion/etc. effects in older games (usually 2006 and prior, mostly the stuff you'd find on GOG.com nowadays) that go entirely missing if the hardware can't process them. USB DACs fare even worse than a typical Realtek audio codec there, since they don't even support EAX 1/2 or have any means of wrapping DirectSound3D API calls into OpenAL to process them. (Realtek at least has 3DSoundBack, or if you're willing to fiddle around with those X-Fi MB2 software packages, ALchemy.) You could use SniperCzar's Windows 7 trick with a USB DAC (set sound device with EAX support as primary, then set its Stereo Mix/"What U Hear" recording input to playback through the USB DAC through the Listen tab in its Properties window), but this is said to add some slight latency, and I don't know about how good the actual audio quality will turn out.