need some help with ported side of 4th order

[tuckintaco93]

i have the sealed side at 6 cubes and the ported side at 12 , need help with port size box is 38" wide would like to have port that wide how tall and long should it befor 50 hz , this is for 2 kicker l7 15's

[tuckintaco93]

i used the cal on 12volt .com and it gave me 12" long port for 38" wide and 8" tall , and will work out good cause the port is going over the sealed side and its 12" , so would this work ? i have never built a 4th order box