Loud Air Vents at max setting

[Ravs88]

Hi all

Can someone put my mind at ease. I have an Audi A5 b8.5 model. The air vents when turned to max (12), seem to be loud - best way I could describe it is like a humming/jet engine type of noise. If I turn it down to 10, it disappears.  Is this sort of noise normal, I can attempt to take a video or sound to demonstrate but if anyone can check that'll be great

By the way, I have attempted to play around with the settings i.e. Sync settings, changing air-flow etc

Thanks

Ravi