Analog 5.1 - Surround ALSO Coming Out Of Front Channels

Hello,

I am using the latest OpenELEC 3.0.1 release with XBMC 12.2. My 5.1 analog out works fine at the ALSA level, so I assumed this to be an XBMC issue and not an OpenELEC issue..thus posting here.

My motherboard has only 3 jacks, so I added the following to the ALSA config:

options snd-hda-intel model=3stack-6ch enable=1

I used amixer to set 6 channels:

amixer -q set 'Channel Mode' '6ch'

I was able to successfully test using the following:

speaker-test -t wav -W /storage/videos/alsa -D surround51 -c 6cd

(ignore the -W, that's just necessary because OpenELEC doesn't come with the ALSA test wav's, so I had to move them in from somewhere else)

Then I go into XBMC and set to 5.1 output. Unfortunately, I can't set a custom output device to surround51 - I just have to hope XBMC does the right thing.

I tried an AVIA test DVD, and also a surround video downloaded from the internet - both giving me the same results. Basically, my setup "mostly" works...but, the rear left channel is ALSO coming out of the front left, and the rear right channel is ALSO coming out of the front right.

I've been reading a bit, but I just don't know where to go from here. It seems that if I could verify XBMC was actually using the same surround51 device that speaker-test was using, then that would be something. Where does this channel duplication come in?

BTW, OpenELEC doesn't have alsamixer...only amixer. I'll appreciate advice. My mobo is a gen 1 Ion...Zotac Ionitx-b-e I think.