Cfrgtkky

I follow this guide to get my 5.1 audio working: https://help.ubuntu.com/community/DigitalAC-3Pulseaudio and it has been working for some time now in 18.04 (and before in 17.10)

Starting around Nov 13th? (could have been a bit earlier since I didn't reboot in a while) I noticed my audio stopped working. I noticed the profile for the card was no longer set correctly and I fixed it with pavucontrol.

I then noticed though the return of a very loud jarring glitchy sound that is emitted anytime a new audio stream is started (and when opening pavucontrol), but otherwise seems to be working. I can do the speaker test in the sound settings and hear all 6 speakers. Also I noticed sometimes when no audio is playing for a while, I start to hear a buzz, which goes away when a new audio stream is played (after the loud screech subsides).

I actually had the loud noise before and solved it by adding tsched=0 to my /etc/pulse/default.pa and /etc/pulse/system.pa file on this line:load-module module-udev-detect tsched=0 however this does not seem to be working anymore. I tried setting it to 1, or removing tsched with no effect.

I suspect some update caused this, but can't figure out which one. I tired reverting to 4.0.15-34 since it changed around that time, but for some reason, no audio devices show up with that kernel except "dummy", also networking does not work, even though I installed the -modules package as well.

Any tips on debugging this?

Finally I found this post How to enable 5.1 channel playback on a Realtek ALC887-VD chip?

The solution was to open alsamixer, select your sound card and set channels to 6, even though I set default channels to 6 in the pulse daemon.conf file already. Moreover the gnome audio settings behaves badly with 5.1. You have to use pavucontrol to select the correct profile. ONLY use the gnome sound settings to select the 5.1 output device, if you touch the profile dropdown box, the output device completely disappears from the list!