I am designing an enclosure for a Sundown Audio Z-15 (D4 wired to 2 ohms on a Sundown Audio SAZ-2000D), it will be a daily driver. I listen to a lot of chopped and screwed, r&b, old school and rap so I decided to stick with 31Hz. This may be a temporary box or a full time box depending on how it and the sub treat me. I havent build a box since August of 2008 so its been a while, my max dimensions are 16.5"H x 34"W x 21"D. Jacob told me I can make the enclosure as big as 4ft^3 and tuning anywhere from 30-35Hz and 28Hz if I wanna go lower. So right now Im sitting with a box at 3.85ft^3 @ 31hz with 60 in^2 of port area (port area range = 46-62in^2). Made of 3/4" mdf, standard slot port (l-shaped) opening. Enclosure Dimensions Outside = 16.5"H x 33"W x 20"D Port = 15"H x 4"W x 29.75"D Sub Displacement = 0.19ft^3 Physical Port Length = 15.25" Cut-Out Baffles Back = 33" x 15" Front = 28.25" x 15" Right Side = 18.5" x 15" Left Side = 19.25" x 15" Port 1 = 14.5" x 15" Port 2= 7.75" x 15" Bottom/Top = 33" x 20" (2) Thanks for help, if there need to be any corrections than let me know I would appreciate it. I got the specs from two different box designing programs.