Noise from the eaves: non-return flap and wind roar - the reason? What is the na

Hello everyone,

please help me with the noise from my hood. My hood, which has an exit from the kitchen, through the next room, straight to the roof (photo in the attachment) makes noise when the wind blows (it doesn't have to blow hard for this effect). I am talking here about the loud sound of the wind from the outside (the hood pipe acts as a loudspeaker) and when it blows stronger, there is a clatter of the backflow flap in the pipe. Unfortunately, where I live, it blows practically non-stop! What is the reason, firstly, for 1) the roar of the wind coming out of the eaves and, secondly, 2) for lifting the non-return flap? The ventilation outlet (in the picture) is completely enclosed, so theoretically there should be no problem? Is it possible that the exit is horizontal and not vertical (standard) like the chimney in the picture and the ventilation of the apartment next door?

I would like to point out that I cannot get to the check valve in the hood because it is built-in.

I will gladly bring a specialist here, but I do not know the name of the specialist who deals with hoods / ventilation?

Thank you very much for help!

Chimney sweeps provide ventilation. In my opinion, this outlet above the roof is made too low. The fact that the non-return flap closes/opens proves that there is negative pressure in the house and air would like to enter through the hood. The noise is probably caused by the use of a rigid connection made of some plastic fittings or thin sheet metal.

Added after 5 [minutes]:

It seems to me that adding a few elbows or possibly arranging the ventilation duct in the so-called siphon (you would have to make a condensate drain) + covering the duct with something heavy, e.g. mats to soundproof the car door, will solve your problem.

Yes, I read that the hatch opens and closes due to the vacuum, but when I open the window in the kitchen, it doesn't change anything, and it should because it equalizes the pressure in the room?

I found a roofer who said the same thing that the outlet is made too low so they will pull it up a little, vertically and make a round roof. Apparently he has help. what do you mean?