P5Q Pro/HD4870 only feeding stereo audio through coax/HDMI, respectively?

[cykbryk]

My P5Q through digital coaxial and the R4870 through HDMI only output audio in stereo.
Since both audio outs use different hardware (video card vs. on-board audio) and different outs (I/O panel coax out vs audio over HDMI) the issue must lie with the software.
I tried configuring speakers for both devices through Vista's (64-bit, by the way), but it either won't let me configure speakers at all (<Configure> button is greyed-out) or the only option is stereo.
The only audio-out that I can configure speakers for is the 6-channel direct (1/8" headphone jacks) but I can't use that for this application.
How do I fix that so I can enjoy 5.1 audio while playing PC games on my 50"?

 

[cykbryk]

Bump.

 

[VirtualLarry]

How do I fix that so I can enjoy 5.1 audio while playing PC games on my 50"?

As far as I know, you cannot. 5.1 is just passthrough for pre-encoded content like DVDs. Games generate their audio dynamically, and your soundcard doesn't encode multi-channel audio.

 

[eklock2000]

I use SPDIF optical out on the mobo straight into my receiver? Video is sent directly to my 46" Samsung via HDMI. I read your specs and saw you're using z5500 and not a receiver. Sorry couldn't be of more help.

EK2K

 

[cykbryk]

As far as I know, you cannot. 5.1 is just passthrough for pre-encoded content like DVDs. Games generate their audio dynamically, and your soundcard doesn't encode multi-channel audio.

The audio chip on my motherboard is a Realtek ALC1200, and supports 7.1 audio, so it should feed just that through any of the audio conenctors I select, or at least S/PDIF.