Comment 49 for bug 1040873

for now best i have acheived is:
- pins configured as #2 solution says (first post in this bug report)
- in /etc/pulse/daemon.conf you need to enable this option:
 enable-lfe-remixing = yes

 with this option you wont have to change profiles each time song changes to get woofer working
- use a 'daemon' from this bug report (post #41) or my little changed ver (it shows 'ubuntus' notifications when plugged etc)

this setup 'tries' to play correctly when you provide 5.1 input - try with some movie - credits have some music
the woofer tries to play only basses - the problem is that they are not clean and loud - havent figured out why yet.
when you provide stereo input it plays left/right channel (all the tonnes)
theoretically this option: enable-remixing = yes in /etc/pulse/daemon.conf should fix it (it should do 'low-pass' filter and the woofer should get only basses)
but it doesnt work - setting custom channel-map / default-sample-channels helps nothing
setting in /etc/pulse/default.pa
load-module module-alsa-sink device=hw:0 channels=6 channel_map=here many different channel mappings(same num as channels num)
also helps nothing

normally when set 5.1 profile - the woffer loudness is affected also by front-left/right volume (the volume sliders in pavucontrol)
but when you add to the /etc/pulse/default.pa this line:
load-module module-combine channels=3 channel_map=front-left,front-right,lfe
you will see in pavucontrol another set of sliders left right woffer
put these 5.1 sliders to the eg. 50 / 100%
play some music (can be stereo) doesnt matter, in pavucontrol (playback tab) set your music app so it will play to the 'simultaneous output to built-in audio analog surround 5.1'
go to output devices tab and now front-left / right doesnt change the volume of the woffer - can mute both and the woffer will just play (you need to use these new added set of sliders (these 3)) - not the default 5.1 sliders
prolly its not 'ready' / nice to use but its good for testing - you can hear what your woffer really is playing etc.
if someone wants this option - you can add it to the 'daemon' script - so it will load / unload that module when you plug/unplug the speaker (using pacmd or smth.)
also be sure to restart pulse every time you change its config files: pulseaudio --kill should do the job (it should autospawn after few secs) if not just use pulseaudio --start (do these as nonroot user)

whats left is to force pulseaudio to 'create the basses' on the fly (lowpass filter) - maybe then it wont play left/right channel
if someone has any idea how to improve it - feel free i can test