I am building a box to custom fit in the x-cab of my truck for 2 15 inch Audiobahn High Excursions. I called audiobahn and they told me the exact dimensions for the port and everything i wanted for my particular box size. They also helped me in tuning the box for the frequencies i wanted. They were really good to work with. I would call audiobahn and ask them. By the way, they reccomend 2.9 cubic feet for a ported box with that sub. My box is going to be 10.6 cubic feet. They gave me the port size at 70 square inches at the opening and 8.25 inches deep. Call them and ask them exactly what you need for your application. They will hook ya up. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif