inserted USB headset and got "static" over my audio headphones

I connected my USB Jabra headphones to test out audio calling which seems to work much better with the compiled version of chromium; however, I noticed that after doing so, I am getting "static" over my audio headphones.

I did manage to turn it off by installing umix and then fiddling around with various knobs until the "static" went away.

My question is what happened and why? When I used my USB headphones to make an echo call, it sounded clear, not overmodulated or anything, so I don't believe the gain or anything was unreasonable. I also tried rebooting (and leaving the USB headset disconnected, I did manually unload the snd_uaudio, but to no avail, hence why I hoped a reboot might help) because I wasn't sure what settings might exist in memory, but that didn't help.

Steps I did:
pkg install -y umix

umix -d /dev/mixer4 rec 0
umix -d /dev/mixer4 igain 0

The one that did it was setting igain to 0, it was previously set to 4 and rec was 35.

So, something is setting that automatically, or are my settings persisted somewhere?