Here's my design, if you have any suggestions please, I'm going for spl and still want some power down in the 30hz area. My box now is 3.6cubic ft 44hz.
28" wide, 27" high, 16" deep.
Port: 27" wide, 1" high, 5.7" deep.
5.6 cubic ft, sub is .7 cubic ft, - 4.9 cubic ft box
port tuned at 42 Hz...