I'd make the box atleast 16" tall, and from your port specs, it sound like you'll have to make the box atleast 23" deep (you usually need atleast 3 or 4" from the end of the port to the back of the box). Keep in mind that you will have to take into consideration the width of the mdf board (3/4")...so work that into your dimensions. I'm not too sure about that "L" shaped port, I would guess it wouldn't work too well. You might want to consider two 10" ports vertically on each side of the sub. I'll try to draw something up for you and post it up. And yeah, you'll probably want to make the box about .2 cubic feet bigger to compensate for the sub's displacement.

*edit*
I just did some calculations and with the given port depth, it's virutally impossible to create a rectangular box much less than 4 cubic sq. ft.. Is the recommended air space they gave you a minimum? Will it work as well/better in a larger box or what?

 

I'd go with something like this at 23" deep total, ports 19.5" deep....if sub specs allow a slightly larger enclosure.

 

nice design..

 

very nice. i didnt think about the two slotted ports. i like that better actually gives it a nicer look. and would work better for me. if i make the box 23" deep ill just have to cut out a chunk in my false floor for my tire well. luckily i havent gotten that diamond plated or itd be pissed. ill probably use ur design. ill call treo one more time to make sure i can build the box bigger than supposed to. the dimensions he gave me are supposed to be so that the sub will play at full potential i guess. ill update.

also got the amp rack to fit today and it looks 10x better. just got to get it fabricated now. thats my aunts job

 

also about ur design the width of the box (16.5) isnt that to small? cause if the port is 2 in. wide thatll leave me 14.5in. of room left the sub wouldnt fit. unless what ur saying is add 2in. to 16.5. then itd make more sense.

 

i think he means the 16.5 between the 2 ports whcih leaves enough room for a 15..so add 4 inches to the 16.5

 

For real, basicly any wood beside particle board or MDF will either leak or absorb the sound. Maybe thats why it didnt get that loud ?

 

WHOA WHOA WHOA HOLD ON

before you go and try and make this dual port box, I read dual ports tuned the box differently. Do ur homework b4 u go out and try it. Not to diss you John but before I tryed making a ported box for my type E's outta 4" pvc but a single port wouldnt be enough but if I used 2 it would. I did my research and accually found out 2 ports wont be the same as 1 port. Just a heads up

 

afboy, u think the L shaped port would be better. cause theres no way im gonna do a 40 inch long port. also lets meet up at the car show and let me buy those fans off u please. really want em now. changed my whole design sorta with my amp rack and xbox better things now.

 

Eli,
I know ur prolly gonna hate me but im going to be outta town this weekend to chicago so the next time i can go to one is next next friday. If u really need em PM me and ill give u my cell number and we can meet up sometime. As for getting a 40" port, mine is 63" by 3". How is it 63" u ask? it wraps around the back of the box inside, which also acts as a brace.

These plans were made custom for my 15" magnum. 4 cu/ft tuned to 28 hz. If you need box designs, Jmac over on the caraudio.com forums will make them for you for 5" Just tell him what u want. He draws out all the diagrams and tells u all the lengths you need to cut. its nice!