I've just got the Asus N76VZ DH71 with a Sonicmaster subwoofer. I got the output on the sonicmaster, but essential its a right channel, not the sub.
I was following:
to try to fix the Intel Audio bug, but after reboot, Ubuntu does not see any audio device at all.
I had to remove the new 2.1 mapping in
extra-hdmi.conf in order to have it work again.
The Intel Card here is
00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04)