Currently have an Asus N56DP. Using an older answer I could get the subwoofer to work under 12.04 but after an upgrade to 12.10 that method stopped working.
lspci|grep -i audio
00:01.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Trinity HDMI Audio Controller
00:14.2 Audio device: Advanced Micro Devices, Inc. [AMD] FCH Azalia Controller (rev 01)
lsusb
Bus 002 Device 002: ID 1bcf:2883 Sunplus Innovation Technology Inc.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
A bit more info. the fix for the n56v series worked under ubuntu 12.04 to get the subwoofer working but was a bit wonky. The fix was the one that added these lines to /etc/rc.local:
echo 0x1e 0x99130112 > /sys/class/sound/hwC0D0/user_pin_configs
echo 1 > /sys/class/sound/hwC0D0/reconfig
and added this line to /etc/modprobe.d/alsa-base.conf:
options snd-hda-intel model=asus-mode4
lastly, my 13.10 was arrived at by upgrading from 12.04 through each version to 13.10.
Best Answer
I also have an N56DP, the solution is actually simple (It works for me on Ubuntu 14.04, i don't know about other versions.) First undo all the other junk you did, No need of messing with any conf files. Download alsa-tools-gui, open hdajackretask, switch to the realtek card and select show unconnected pins. Override the following:- 14- line out center 15- line out center 16- internal speaker lfe 17- internal speaker lfe 18- line out center 1a- line out front 1b- line out back 1e- spdif out
Note this config enables subwoofer to play the low frequency from the right speaker (this is the standard in windows) By messing around you can try other configurations (I have not tried them all) One configuration i particularly liked turned my mic input into a second headphone jack.