asound.conf

pcm.dmixed {
	type asym
	playback.pcm {
		# See plugin:dmix at http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html
		type dmix

		# Don't block other users, e.g. the Timidity midi-player daemon
		# http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html
		ipc_key_add_uid true

		ipc_key 5678293
		ipc_perm 0660
		ipc_gid audio

		slave {
			# 2 for stereo, 6 for surround51, 8 for surround71
			channels 6
			pcm {
				format S32_LE
				#format S16_LE

				#rate 44100
				rate 96000

				# http://www.alsa-project.org/alsa-doc/alsa-lib/pcm_plugins.html
				nonblock true

				type hw
				card 0
				device 0
				subdevice 0
			}

			period_size 1024

			# If too large, use CONFIG_SND_HDA_PREALLOC_SIZE=2048
			buffer_size 16384
		}
	}
	capture.pcm "hw:0"
}

pcm.!default{
	type plug
	slave.pcm "upmix20_51"
}

pcm.!surround20 {
	type plug
	slave.pcm "upmix20_51"
}

pcm.!surround40 {
	type plug
	slave.pcm "dmixed"
	route_policy duplicate
}

pcm.!surround51 {
	type plug
	slave.pcm "dmixed"
}

pcm.upmix20_51 {
        slave.pcm "dmixed"
        slave.channels 6
	type route

        # Front and rear
        ttable.0.0 0.9
        ttable.1.1 0.9
        ttable.2.2 1
        ttable.3.3 1

        # Center and LFE
        ttable.4.4 1
        ttable.5.5 1

        # Front left/right to center
        ttable.0.4 0.5
        ttable.1.4 0.5

        # Front left/right to rear
        ttable.0.2 0.5
        ttable.1.3 0.5
}