Quiet 40mm Fan Grille

So I was using a fan grille that I had found on here, and printed to make my printer look cooler. However it made my hot end fan very noisy. I realized it was causing the fan blade to chop the air, which kinda how air raid sirens work.

It also caused the fan to speed up, which means less air flow.
Don't believe me?
Cover the intake on your hair dryer it speeds up, and the air flow stops. It's like spinning in a vacuum it's not doing as much work but it's getting the same amount of power.