So about 3 months ago or so I had got a webcam and a headset, everything worked fine for a while, then I heard my voice cutting out every 2 seconds and people couldn’t hear me, they would say things like “What?”, and of course I had voice_loopback on 1 so I could hear myself like this, and it was very weird. It stopped working with both of my mics, the one on the webcam, and the one on the headset. I’ve tried changing sound drivers, and I’ve looked up a Google search on it, didn’t find anything. I do NOT want to uninstall GMod, though.
Have a look at this:
you should also try unplugging it and making sure it’s plugged in correctly. Even if it’s a USB headset or some variant.
I’ve unplugged and replugged (during in-game the process to plug it back in will take it longer than when I’m not in a game) both of them, when my headset stopped working I used my webcam mic and it didn’t work. To note, that they work in desktop-related mic programs such as Skype and TeamSpeak. It also works in TF2, and CS:S, but not GMod. It was the weirdest thing when it happened.