asoundrc

pcm.hda-intel {
	type hw
	card 0
}

ctl.hda-intel {
	type hw
	card 0
}

pcm.snd_card {
	type hw
	card 0 # change to your cards number or name
}

# 6 channel dmix:
pcm.dmix6 {
	type dmix
	ipc_key 1024
	ipc_key_add_uid false # let multiple users share
	ipc_perm 0660 # IPC permissions (octal, default 0600)
	slave {
		pcm snd_card # see below
			rate 48000
			channels 6
			period_time 0
			period_size 1024 # try 2048 against skipping
			buffer_time 0
			buffer_size 5120 # in case of problems reduce this
# in case of skipping, try increasing
	}
}

pcm.jackplug {
	type plug
	slave { pcm "jack" }
}

pcm.jack {
	type jack
		playback_ports {
			0 alsa_pcm:playback_1
			1 alsa_pcm:playback_2
		}
	capture_ports {
		0 alsa_pcm:capture_1
		1 alsa_pcm:capture_2
	}
}

# upmixing: 
pcm.ch51dup {
        type route
        slave.pcm dmix6
        slave.channels 6
        ttable.0.0 1
        ttable.1.1 1
        ttable.0.2 1
        ttable.1.3 1
        ttable.0.4 0.5
        ttable.1.4 0.5
        ttable.0.5 0.5
        ttable.1.5 0.5
   }

pcm.duplex {
     type asym
	 playback.pcm "51to2m"
#     playback.pcm "ch51dup" # upmix first
#     playback.pcm "dmix6"  # just pass to 6 channel dmix
#     capture.pcm "dsnoop:0" # doesn't work for me
     capture.pcm "snd_card"
}

# change default device:
pcm.!default {
     type plug
     slave.pcm "duplex"
}

# for aoss
pcm.dsp "duplex"

pcm.dsp1 "duplex"

pcm.51to2m {
    # This is like the pcm51to40 from
    # http://www.halfgaar.net/surround-sound-in-linux
    # but meant to use Dolby Surround (2.0 Matrix encoded)
    type route
    slave.pcm surround51
    slave.channels 6

# 0 - Front Left
    ttable.0.0 1
# 1 - Front Right
    ttable.1.1 1
# 2 - Rear Left
    # TODO: get -90 phase shift
    ttable.2.0 0.5
# 3 - Rear Right
    # TODO: get +90 phase shift
    ttable.3.1 0.5
# 4 - Center
# Center channel routing (routed to front-left and front-right),
# 6dB gaindrop (gain of 0.5) per channel
    ttable.4.0 0.5
    ttable.4.1 0.5
# 5 - LFE
# LFE channel routing (routed to front-left and front-right),
# 6dB gaindrop (gain of 0.5) per channel
    ttable.5.0 0.5
    ttable.5.1 0.5
}