I have an Intel ALC892 and a Nvidia GT 520m connected to speakers via HDMI.

On lspci, I see

00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02)
    Subsystem: ZOTAC International (MCO) Ltd. Device a218
    Flags: bus master, fast devsel, latency 0, IRQ 47
    Memory at db400000 (64-bit, non-prefetchable) [size=16K]
    Capabilities: [50] Power Management version 2
    Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
    Capabilities: [100] Virtual Channel


02:00.1 Audio device: NVIDIA Corporation HDMI Audio stub (rev a1)
    Subsystem: ZOTAC International (MCO) Ltd. Device 2180
    Flags: bus master, fast devsel, latency 0, IRQ 18
    Memory at db080000 (32-bit, non-prefetchable) [size=16K]
    Capabilities: [60] Power Management version 3
    Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [78] Express Endpoint, MSI 00
    Kernel driver in use: snd_hda_intel

My alsamixer looks like

I enabled pulseaudio configuration file to have 6 channels. My sound setting looks like

When I use the test dialog, only front left and right have sounds. If I use alsa in XBMC on a 5.1 video, there's no sound. If I use pulseaudio, only front right and left have sound. I can barely hear any speech since I'm guessing it's mapped to front center. Any clues?