I have an external GPU which emits a whining sound with the loudest band at ~6500hz and has harmonics at +/- multiples of ~1600hz from that point. Is it possible to design a grate of some kind that would allow airflow to the components, but would attenuate these specific frequencies? I think cutting 6500hz down may be sufficient for this to stop bothering me so much.
Specifically, I'm using the Pro version of the Blackmagic eGPU, which has a Vega 56 and lets airflow pass through both the bottom and top of the unit. I believe most of the sound leakage comes from the top side of the unit. It is not user-servicable, so I'd rather not open it up and would prefer to put something on top of it.