[boosted]

This is how I got HDMI audio and DTS / AC3 passthrough to work. I have an NVidia GTX460 connected to my receiver. I have onboard audio disabled in the BIOS.

Run aplay -l in a terminal window

Code:

aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 7: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 8: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 9: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Through trial and error I found that 'device 7' works for me by changing the following. You can see it's card 0 and device 7 on mine
Allways backup files first.

Add / modify /etc/asound.conf

Code:

pcm.!default {
    type hw
    card 0
    device 7
}

ctl.!default {
    type hw          
    card 0
    device 7
}

If you are running pulseaudio add the following to /etc/pulse/default.pa

Code:

load-module module-alsa-sink device=hw:0,7

in xbmc audio options set

Code:

Audio output                       HDMI
Speaker Configuration              5.1
Enable AC3 and DTS
Audio output                       custom
                                   hw:0,7
Passthrough output                 custom
                                   hw:0,7