I just read the my sub displacement is 0.067cu.ft, my net volume is

15.74x14x13.4), so its 1.7-0.067=1.633??, i must use this volume in the formula to find port area and length i guess:S, with a port of(3x7.4) and a length of 37",i will fix the port from the outside, am i correct this time?//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

forget about the 5.5" dimension thing on the pic , all dimensions on the pic are ramdomly chosen, i will have en external port of (3x7.4) 37" long, would it be right in order to have a box of 1.6ft^3 tuned to 30Hz? and is it good for a ts-W12prs sub?
thx a lot