I'm not an expert, but from what an audiophile friend of mine told me many years ago is, your ports are too small (diameter wise).. you are trying to push air through them faster than they can easily flow.. if you increase the diameter, more air can flow in the same amount of time.. This should reduce the 'air noise' significantly..
I'd immagine you would have to make the ports shorter when you open the diameter.. not sure if your box will allow that or not.. And, I'm not sure if you would have to change the volume of the box on a bandpass for different porting.. but I'd immagine that math says you can keep all other things constant (box volume/tuned freq. etc) and get new values for just ports (increase diameter, see what you get for length).. the problem there is, you could physically pass limits (get a length of say, -2 inces for the port, but increasing/decreasing the volume of the box would bring it to the right side again)..
I'd say re-calc your port length on a bigger diameter and see what you come up with for numbers.. if it's doable, that should clear up your noise problem..
Hope that helps (and is right)