Unfortunately, if you have a really sensitive microphone, your silence might be detected as not-loud-enough-speech, and the microphone input volume gets turned to maximum. Then, the next time you speak, the sound will be distorted and way too loud!
The extension Disable Automatic Gain Control for Chrome seemed nice, but unfortunately will not work for Desktop applications, nor does it work reliably in all browser based tools.
Instead of trying to find even more clever ways of somehow detecting and then preventing gain changes, a simple Apple Script will fix this issue:
set initialInputVolume to input volume of (get volume settings) repeat set volume input volume initialInputVolume end repeat
Save this as a
.scpt file, within the MacOS tool called
Script Editor, and run it before you run whichever tool messes with your audio settings.
It will read the current input volume, and continually set it back to whatever it was when the script started, overriding any attempts of third party apps to change those settings.