I need to know how many tubes I would need and what length and what diameter opening to reach like 30hz in 3 cubes... with at least 36-48 square inches of port.

And I also need to know the displacement of these I can't seem to figure it out.

Take a look at 12volt.com or something like that.

surface of a circle : pi * r^2

volume of a round tube : pi * r^2 * length

I don't know how to say it in English, but r = half of the diameter.

correct me if I'm wrong, but I'm not !!!!!!!!!!!!!!!!!!!!!!!!

Correct, the area of a circle = pi*r²

r = Radius

Another thing to remember is with a areo port the drag within the port is much lower than a slot of the same area and therefore when using aero ports you can get away with less area and achieve the same flow