my pulseaudio config

daemon.conf

[...]

default-sample-format = s32le
default-sample-rate = 48000
default-sample-channels = 6

enable-remixing = yes
enable-lfe-remixing = yes

flat-volumes = no

default.pa

[...]

# map front, side and lfe/ctr to 5.1 soundsystem
load-module module-remap-sink sink_name=speakers sink_properties=device.description="5.1\ Soundsystem" remix=no master=alsa_output.pci-0000_04_04.0.analog-surround-71 channels=6 master_channel_map=front-left,front-right,side-left,side-right,front-center,lfe channel_map=front-left,front-right,side-left,side-right,front-center,lfe

# map rear to stereo headphone
load-module module-remap-sink sink_name=headphone sink_properties=device.description="Headphone" remix=no master=alsa_output.pci-0000_04_04.0.analog-surround-71 channels=2 master_channel_map=rear-left,rear-right channel_map=front-left,front-right

# mic preview, somehow produces high load...
#load-module module-loopback latency_msec=1 source=alsa_input.pci-0000_04_04.0.analog-stereo sink=headphone

set-default-sink speakers