The ports have nothing to do with it, other than contolling volume and efficiency. The bass wavelengths are longer than your room.
I would advise moving your subs around until you get a balanced bass response with the least room resonance. You should get good results with two subs (it can be done with one, but you will limit your listening positions).
I would advise moving your subs around until you get a balanced bass response with the least room resonance. You should get good results with two subs (it can be done with one, but you will limit your listening positions).