Sound not working on ubuntu 18.04 after some mess-up by me

Question

I am new to ubuntu. I wanted to run some signal processing programs, so I installed jack. But it wasnt working. I messed something up while figuring things out. Now the audio doesnt work. I carried out all the steps mentioned here: https://help.ubuntu.com/community/SoundTroubleshootingProcedure

I also followed the steps given in this answer: How to reinstall PulseAudio (Ubuntu 12.04).

But i couldn't solve my issue.

When i play something in rythymbox, everything else works fine. The sound also shows up in the pavucontrol. It just isnt audible. I obviously checked for all volumes in ALSA mixer and gnome alsa mixer and all were full.

What could be the problem? Is there any way in which I can revert all my sound settings back to as it was when i installed ubuntu?

Answer 1

Do not use information related to Ubuntu 12.04 for 18.04
It will not work because of changes in just Pulseaudio over last 6 years,
probably many other changes in Ubuntu too

There is a package pulseaudio-module-jack to make Pulseaudio connection to JACK
It is not a required dependency for JACK or Pulseaudio so may need to be installed

Suggest using QjackCtl or Cadence to start JACK and Pulseaudio connections

Playback connection for Pulseaudio can be added after JACK started with:
pactl load-module module-jack-sink

Sound in Pulseaudio will still be trying to use ALSA device now used by JACK

But pavucontrol -t 1 will now show drop-down menu option to change audio stream playback to JACK

Suggest using command Pacmd set-default-Sink PulseAudio\ JACK\ Sink
(Setting requires Pulseaudio be restarted - logout or reboot) Audio streams will use JACK playback by default, but fallback to ALSA device if JACK connection not available

Manually changing playback usually only required once for any type of playback stream,
pavucontrol saves Pulseaudio settings (other panel controls and DE tools may not)

Playback should normally work playing Pulseaudio > ALSA and switch to Pulseaudio > JACK > ALSA when JACK started, but can sometimes break Pulseaudio settings
For better reliability, clear playback streams in Pulseaudio completely before starting JACK

Answer 2

I did the steps mentioned by nic gnomic. Still it didn't work. I eventually found out that the problrm was due to dualbooting Ubuntu with windows 10. This problem only arises if i reboot into ubuntu from windows. At all other times, sound works well.