[larrik]

They measured the intake side, though, so it was more of a vacuum effect. Would a windscreen still make a difference in that scenario?

[oliveshell]

I can’t think of why not. The velocity might be lower, but moving air is moving air.

[robmiller]

Yes, I agree. Inlet side is quieter than discharge for most fan types (propeller, centrifugal, etc), but noise due to air movement are on both sides.