What sound frequencies can pass through a hole in a wall?

[sophiecentaur]

I am not a troll. The task I am solving sounds exactly like that

No. Not at all. Your basic problem is almost universal for building design.

Thing is, you would be far better off doing a Google search to find more precisely what you need. My first Google hit was this link which provides "some kind of formula". There were many others and I suggest you go down the same path.
When you find something that looks the right level, ask PF again to clear up particular problems. you find there. Otherwise, it can turn out to be too open ended for PF to help.

 

[ProfRob]

I am very new here....and yet I found the question interesting. I have been wondering the same thing myself. Another approach to the problem might be to ask, "what theories come into play" with this problem? If we knew the major theories involved, we should be able to learn and solve the problem on our own. Please don't give up on the question, keep it very simple - at the theoretical level. Thanks you, Rob