Reposting answer from reddit to here since I removed it. This issue was MX3 initially, but seems to be related to some other headphone DAC/AMPs

The issue is either in windows or some kind of feedback near the DAC.

Feedback from other power sources near your headphone wire, something as small as a bluetooth mouse in between my headphones triggers this. The amount of interference from other devices is REALLY SMALL, make sure no power cables or such are near your aux.

Legal bullshit below by not-a-lawyer.

Now I don't want this answer to go back into reddit so...

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