Comment 12 for bug 1302090

do the subwoofer need both left and right channel ?

try hda-analyer to change the volume sliders of audio mixer which is connected to subwoofet (node 0x0d ?）

speaker-test -c2 -t wave -D hw:0,0

do it work with 2.1 mode ?

https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1286021