Old question, I know. Use an USB isolator like this:
Less than 10 dollars on aliexpress.
What it does:
Isolate ground (lift ground) on the USB connection with isolated DC/DC converter to eliminate ground loop/noise.
Generally, open-back headphones are better for mixing purposes. There are multiple reasons for this, you accumulate too much of the sub-region in closed-back and you don't hear the sound as clear, you get ear fatigue faster with closed, and the small subtle details of a sound stand out much more with open-backs. Some of the more expensive pairs are in the ...