Hey y'all!
Bit of an odd situation.
I'm trying to hook up my rig to my little home theater setup so that way I can play MKVs in front of my ungodly comfortable couch. Unfortunately, I'm having no luck getting the audio to play on the speakers.
Set up is as follows:

EVGA 970 FTW
      \/
30 Ft Redmere HDMI cable
      \/
Monoprice 4x1 HDMI switch w/ Audio extractor
 Audio \/              \/ Video
Sound Bar             TV

This works just fine for my PS3, XBox 360 and ChromeCast. Video goes to TV, 5.1 Audio goes to sound bar.
However, with my PC, I only get video and stereo sound. In the playback devices section, it clearly recognizes the audio capabilities of the Switch/Sound bar, but it won't play anything beyond Stereo. (It actually recognizes more than it's capability, which I think is a problem with the cable, but I still have issues with other cables.)
Additionally, I have a sound card in my system, a Xonar Essence STX. It shouldn't be interfering, but it's always possible. I don't have it hooked up directly to the sound bar because I'm trying to keep the complexity of the system down. I already have 3 remotes as it is.
The HDMI switch in question: 

 
 
If you guys can give me any insight or direction, I'd greatly appreciate it!