You thought that the helicopter was built into the headphones? Lmao! That's a fun one.
But seriously folks, move the fan wires as far away from the data and audio cables as possible. Separate audio, data and power wires until you find the position that bleeds the least noise.
Noise like that usually originates where wires have been tightly tied together, allowing power supply or data noise to bleed into the audio chain. Using a power supply with high quality filtering and lots of wattage, may help get rid of some or all noise, but try separating the wires first.
And then if all that fails, it could be that the motherboard just doesn't have high quality audio design. The noise could also possibly come from internet modem (try disconnecting and retest) cable TV, power line noise, RFI interference, etc...