Although this question has been addressed at this link, none of the solutions worked for me and they are mostly from several years ago (I tried 3 or 4 of them and left comments too).
The problem I'm having is that the mic input level (in the sound panel of system preferences) keeps decreasing automatically. Each time I reset the audio input level back to 100% my problem is solved. I want to be able to have it just stay put without readjusting.
Here's more detail: I'm using a language learning website that has an interactive feature that allows me to record myself saying a phrase so that it can then check if I've repeated the phrase correctly. But I find that as I'm using this record feature, the input mic level in the system preferences starts to decrease over time. So I end up repeatedly adjusting the mic input level back to 100% and it works well again.
I'm using the Chrome browser on Mac 10.13.6 with a MacBook Pro 2015