Weird Mic-In Audio Buzzing

I'm running my console audio, from my TV, through my PC to use my PC speaker system. A white and Red audio going in to the mic port from my motherboard. On the microphone settings 'listen' is checked so that the console audio is coming through. Unless I unplug or disable the port there is a horrible but relatively low level static buzzing noise coming through the speakers. Why is this? What can I do about it? Is there a better way of getting my console audio to my PC that wouldn't do this?

My PC's main monitor is my TV, which has terrible audio. That's the reason I'm doing this.

Typically that sort of buzz or hum is caused by some sort of ground loop. Unfortunately, these sorts of issues are often not all that easy to eliminate. Cables, power supply, and a number of other factors can contribute to it, but it can often be difficult or inconvenient to narrow down the biggest contributors and deal with them.

Does your motherboard have a line in to use instead of a mic port? You might want to try that instead.

If you could get a bluetooth audio transmitter you could connect your tv to that and assuming your motherboard has bluetooth you can send the audio via bluetooth. That would eliminate any physical connection between your tv and the pc which should also help eliminate any ground loops. You could use something like this to turn your L/R signal into a 3.5mm jack and then connect that to something like this. It's a bit of a hack but should work.

Like @chaser324 mentioned though, usually it's caused by a sort of ground loop and it can be tricky to determine how to eliminate it.

Has anyone tried ground loop isolators / filters (like this)?

My new PC setup is connected to TV over HDMI, but I'm listening to audio over headphones connected to PC (front 3.5mm port). PC and TV are connected to different surge protectors on different wall outlets. There's a very low level background buzz, which sounds like what OP described, except I'm not dealing with a mic. (These headphones have a mic built in, but it's on a separate 3.5mm plug, which is not connected.)

The ground loop isolators out there are all cheap enough (<$20), I'll probably just give one a shot and see how it works.