External sound card for Dolby 5.1 audio?

[WhatamIdoingWrong]

My motherboard has a Realtek ALC892 and when using an S/PDIF cable it only outputs 2.1 channel audio when I need Dolby 5.1.
My understanding is that due to the bandwidth, 5.1 channel audio can only be transmitted via S/PDIF once it's compressed in a Dolby format and I'll need a sound card for that? I think I need an external sound card because Crossfire hasn't left me any room to work with inside. Would either of these work? http://www.diamondmm.com/xs71u-diamond-xtreme-sound-usb-audio-device.html http://us.store.creative.com/Creative-Sound-Blaster-XFi-Surround-5.1/M/B0044DEDCA.htm?AID=10274033&PID=6146836&SID=1kikoqxjrzw6
My receiver supports Dolby Digital and Pro Logic 2 if that makes a difference. Any help would be greatly appreciated.

 

[leeb2013]

I had the same issue, games are not dolby encoded 5.1 so don't get sent out over optical. Movies are though. I had to use discrete 5.1 for games, but then realised I should just use the HDMI, which works fine.

 

[WhatamIdoingWrong]

I had the same issue, games are not dolby encoded 5.1 so don't get sent out over optical. Movies are though. I had to use discrete 5.1 for games, but then realised I should just use the HDMI, which works fine.

I would use an HDMI cable, but my receiver doesn't support 3D pass through.

 

[WhatamIdoingWrong]

Could use some help, I'll be ordering a sound card asap if that's what I need.

 

[leeb2013]

only option then is a sound card or discrete 5.1 audio if your amp supports that.

But make sure the sound card also supports Dolby encoding, otherwise no 5.1 game audio will come out of its optical output either!

It's ridiculous, obviously for game devs to save a few $$ on PC games as they don't have to pay the Dolby license.

I believe console games do encode to dolby 5.1, hence no issues using their optical output. PS3 did.