Sealing ported enclosure to reduce boom

Great responses. Actually I stuffed the ports then I took out the woofer to see what was in the cabinet and the woofer is completely sectioned-off with pieces of foam! So I have to find out where the port is getting its bass from: I have to remove the other drivers.

There aren't many placement choices when I room is 13x15. Speakers can only be so close to you. The Cardas site recommends (width of room)x(.447)=distance of speaker front to rear wall. That would be 5.5' for me almost putting them in the middle of the room.
I stuffed the ports and they sound pretty good, much better then when I first auditioned them. But maybe there could be some adverse effects when the woofer is sucking in air thru the port. It might not have enough air available to push as per design.

I stuffed the port with polyfill. I guess if you completely cut off the airflow in the port the movement of the drivers will be compromised.
The ports are shaped like an "L" I think and are big (I can fit my hand inside). I don't know how I would be able to modify the port size without a lot of construction.
I haven't had this problem in this room (and in the same place) with other speakers (B&W, Polk, JBL, Infinity 7).