Microphone not working on Ubuntu 20.04 KDE Plasma with pulseaudio and pavucontrol installed

Question

Microphone is not working on my desktop. What I have tried to:

sudo apt removeauto --purge alsa-base pavucontrol pulseaudio

sudo reboot

sudo apt install alsa-base pavucontrol pulseaudio

Removed pavucontrol and pulse audio. And then micro started working, but no sound control and started to appear error Error loading QML file: file:///home/noah/.local/share/plasma/plasmoids/org.kde.plasma.audiodeviceswitcher/contents/ui/main.qml:29:1: module "org.kde.plasma.private.volume" is not installed
Installed pavucontrol and pulseaudio, rebooted and then sound control came back, error disappeared, but micro stopped working again

I have an external microphone that stopped working with Ubuntu 20.04 but worked fine before. I'm sure it's a bug. Please mention me if you found a corresponding bug issue. ;) — alexanderadam, May 19 '20 at 05:59
Yes I did. This wasn't my problem though. In my case the microphone isn't always recognized since 20.04. — alexanderadam, May 20 '20 at 06:59

score 4 · Accepted Answer · answered Apr 29 '20 at 04:14

Ok, so this is what fixed this issue for me

I think that you may try to go with 'Front Left' to zero instead, based on you mic.

score 1 · Answer 2 · answered May 30 '23 at 14:14

tl;dr

If you are on a laptop trying to use the built-in mic, make sure that you selected the built-in mic with the correct profile and port.

Open "System Settings" and select "Audio".
If there are no recording devices, make sure that the profile for the built-in playback device (Built-in Audio Analog Stereo in this case) has the correct profile selected which is "Analog Stereo Duplex" in this case. If "Analog Stereo Output" is selected instead, the input will not show up.
Check that the correct recording device is selected (Built-in Audio Analog Stereo in this case). The profile should be identical to the profile of the related playback device.
Make sure you selected the correct port. "Internal Microphone" if you would like to use the built-in mic or "Headset" if you plugged in a headset.