https://www.avsforum.com/threads/ground-loop-issue-with-pc-and-subwoofers.3315286/?post_id=63690851#post-63690851

How many threads? Only one is necessary. That way you keep all the responses in one place.

 

My apologies. Not trying to flood the forums; just wasn't sure where the best location was

 

Your quick/cheap fix is to run a toslink for audio.

 

1) Unless he wants uncompressed (excluding PCM stereo) sound/surround.
2) Since he's gaming, he probably wants video too. So... copper still exists creating the possible "ground loop".
3) Does his PC have an optical output?

 

Can you put a PCI audio card in there?

 

No it’s an it’s build and want the audio/ video functionality of a single cable as it’s already ran

 

I had this issue once, the sensible answer is to find a way to plug everything into the same outlet somehow (i.e. get a good quality 12+ port power outlet bar). This is how I fixed mine. In theory I suppose if you did.. a fiber optic HDMI cable, maybe that might fix it if the HDMI cable doesn't have any copper in it? But I've never tried this option. There's some devices out there that supposedly remove subwoofer/audio hum, I looked into them and decided it was a rabbit hole I wasn't willing to get myself into. I was like you originally and felt there was no way to get them onto the same power bar, but eventually I gave up on trying to find workarounds and just did it the proper way by plugging everything (including the PC) into the same power outlet.

 

Cheater Plug (for testing only!): Temporarily try a 3-to-2 prong adapter (cheater plug) on your HTPC to lift the ground and see if the hum stops. If it does, then you've confirmed it’s a ground loop issue. Important: Don’t use this as a permanent solution—it’s just for diagnosis.
Lastly, if you're gaming and tweaking your AV system, maybe give your new gaming PC a break with a little side fun—have you tried testing latency or audio sync using something like a rhythm-based K1 Game Download from obscure indie developers?