My question is whether or not I am enjoying true Dolby Digital Live 5.1 surround sound when playing games like Battlefield 3 and Skyrim.
I purchased Battlefield 3 and learned very quickly that it required a sound card capable of Dolby Digital Live encoding in order to achieve 5.1 surround sound. So I purchased a Sound Blaster X-Fi Titanium sound card. I am using an HDMI cable from my crossfired Radeon HD 6870s to output both the audio and the video to my Pioneer VSX-1121-K 7.1-Channel A/V Receiver.
Now on my receiver I have the surround sound set to PCM, so it means that its receiving a pure digital signal and isn't actually encoding Dolby Digital Live. I am definitely getting 5.1 surround sound in both Battlefield 3 and Skyrim, I guess my main concern is how this is possible?
The sound card is plugged into the motherboard only. The sound card has SPDIF outputs, but I tried using these originally and I couldn't get the things to work so I said the hell with it, fired up my game, and miraculously I am seem to be getting the surround sound I wanted.
Is the sound card actually crunching the Dolby Digital Live encoding and sending this to the video card via the motherboard and then from the video card out to my receiver through the HDMI cable? I find this hard to believe. When I watch movies encoded in DTS or Dolby Digital I typically see the surround sound change on the receiver, but all I have is PCM...?
I'm not 100% sure but... I think your video cards also have sound cards built in (it's not really very expensive) and it's doing all the work and completely bypassing your x-fi.
If you want DTS-connect or DDL to work on an X-fi, open the blue setup panel (the one that let's you select your speaker type and such), click on the encoding panel and choose DTS-connect (or ddl live). After that, it should work fine over spdif.
Dolby Digital live is ONLY need to get 5.1 over the OPTICAL port; you can get surround sound just fine out of HDMI/Analog without having to bother to down-convert audio to Dolby/DTS standards. [Optical does not have the bandwidth to carry multi-channel PCM audio].
So in this case, you HDMI output from the GPU is doing all the audio processing, and sending 5.1 PCM over HDMI. The soundcard is doing nothing.