Realtek HD audio, Optical out. Games in 5.1?

Hey, all.

Recently I hooked up my computer to my HT system so I could stream such things as Netflix and Pandora, and of course do some gaming on the big screen. One thing I was expecting was being able to get 5.1 surround when gaming. I'm not

I suspect it's just the Realtek on board audio that isn't able to do this. Maybe somebody confirm or possibly shed some light on the mater.

Here's my setup and what I've tried so far. My complete computer specs are in my profile.

It's an Abit IP35-pro motherboard with a Realtek 7.1 HD audio.
The HD audio is enable in the BIOS.
I have the latest Realtek driver.
My OS is Vista Ultimate 64 bit.
The game I used was COD4 which has an option to send 5.1 audio.

For the Video I have a DVI to HDMI cable going from my 8800GT to my receiver and for the audio I have an optical cable going from the output on the back panel to the input on my receiver. Funny thing is when I play a DVD I get a 5.1 signal. I just tested it with War of the Worlds and my receiver, when set on "auto" was getting an actual DTS input and not PCM. Anyone who has watched this movie on a HT system with a decent sub knows what a good LFE signal can do to your room. Anyway, I was surprised to see the DTS light up on the receiver. I really didn't think it would decode it.

So that's where I get lost.

Is is the hardware?
A. The sound card is not compatible with 5.1 audio and gaming.
B. It might do 5.1 gaming, but not through the optical output. Just the speaker outputs.

Or is it the software?
The game?
Realtek driver issue?
Vista issue?



I'd really like to get some help before I go and put down the cash on a decent sound card.

Thanks in advance.

Slight correction:

Someone over at AVS responded to a post I made.
Apparently soundcards with DD live will send 5.1 audio from games through the optical output. it's not simulated. Even better if you have a card that does both DD Live and EAX 5.

The question now is does it work with Vista as Vista does not support hardware acceleration like EAX 5. Not sure about DD Live, yet.

I'll explain it this way:

Optical output can only carry a few outputs:
Uncompressed 2.0 PCM (up to 192 KHz/Sec)
Dolby Digital 5.1
DTS 5.1

Both DD/DTS requires that your sound system is able to decode the incoming signal for the output to be sent to your speakers, hence why they are generally not used as output. Instead, 2.0 output is generally upscaled to 5.1 using other methods (DTS Neo PC, Dolby Pro Logic, etc).

To get 'true' 5.1, you either need a receiver/speakers than can decode an incoming DD/DTS signal, or connect using HDMI, which can carry 5.1/7.1 as uncompressed PCM, removing the need for a decoder. Alternativly, you can use the older analog connections to hook an individual speaker to an individual sound channel (still the best option for PC's, for the above reasons).

As for gaming, I know the Realtek chipet supports 7.1 audio on most newer boards. CoD will set your speaker setup to whatever setup Windows is set to use. Go to the sound settings tab on the control panel, and make sure the speaker setup is set to 5.1.

Found this from a google search, I just want to thank you for doing all the research for me.

Well, most soundcards have an optical out and support DDL/DTS-C these days; I'd say that a reciever to decode the resulting signal is more expensive then the soundcard...

Yeah, Soundstorm was awesome back in the day...