So I recently got an Asus G550JK, but it brought Windows 8.1 installed and I can’t make myself like that interface, so I decided it was time to switch over to Linux for good.

While I am a Gentoo fan I currently can’t spend time doing a proper installation, after some tests on a VM decided to go with Mint, while nearly everything worked out of the box the external subwoofer was not working, after a lot of Google searching my solution ended up being a mix of several posts, so to help someone else that may have the same problem as me, here it is the solution.

First install alsa-tools.
Edit the following files and edit/add as needed:

options snd-hda-intel model=,asus-mode4

[Mapping analog-surround-21]
device-strings = surround40:%f
channel-map = front-left,front-right,lfe,lfe
paths-output = analog-output analog-output-speaker
priority = 7
direction = output

enable-lfe-remixing = yes

After editing open hdajackretask, select “show unconnected pins” and select “Realtek ALC668” and override the following pins 0x19 -> “Microphone” and 0x1a -> “Internal speaker (LFE)” and finally click “Install boot override”.

Now reboot the computer and everything should be working.
If anyone has any kind of improvement to my configuration feel free to drop a comment.