Since May 6, after Zorin OS update I have a problem with the microphone. Everything what I say is very loud and distorted. I think maybe headphone drivers broke due to update, but i don't know how to fix it. I will add that the same problem occurs with various headphones and with microphone built into the laptop. Thanks for help.
Are you using alsa-mixer or pavucontrol? Have you checked the mic gains and ensured they aren't up all the way?
Yes, I used Alsamixer, but despite the changes in settings, my voice is too soft or so loud that I can hear noise and distortion.
I'm not completely sure how the software works, but attempt to lower pcm and bring mic just under the red. In the speaker icon on the task bar you may be able to adjust per instance (zoom, game and such). It may take some playing with it to find a happy medium.
Is that screenshot the full extent of your alsamixer [All] channels?
I think that it is impossible to find a happy medium. I tried to find such a setting but still the microphone is not working as it should.
These are all channels from Alsamixer:
More Alsamixer screenshots here, I don't know if they are useful
Your first screenshot showed "Realtek ALC295" but your last screenshot/s show "Nvidia GPU 94 HDMI/DP".
I assume you hit [F6] to switch between Realtek and Nvidia in between times?
My question was, with Realtek ALC295 selected, and [F5] All channels selected, was that the full extent of your alsamixer channels?
Yes, this first screenshot shows all the alsamixer channels.
With All channels listed [F5], I was expecting to see more Mic channels on the right of that screen instead of just a channel labelled "Capture" and two "Mic Boost" channels.
I can only suggest reducing "Mic Boost" to a low level or down to zero.