I have been messing around in audacity, and I found a rather cool phenomenon which I want to fix. When I set up live playback in audacity, I noticed when that when I turn up my mic sensitivity, a strange high-pitched beep appears. I messed around with this, until I realized that my mic was simply bouncing the audio from my headset back and forth. It got louder as the headset got closer to the microphone. Is there a way to make my microphone simply ignore the output of my PC, so when I want high sensitivity and live monitoring at the same time, I don't have to be 10 feet away from my microphone?
It’s called feedback and in your case “spill/bleed” from your headphones.
A microphone’s function is to turn vibrations in the air into and electrical signal. It cannot tell whether the vibrating air is coming from your mouth or your PC or any other source.
If you want to avoid bleeding with higher sensitivity then you need to turn down the headphone volume or you can buy some in ear monitors, because they won’t require as much volume in order to hear what you want.