port placement & box advice 15XXX

[tyranis]

I have 15" RE XXX in my Focus ZX-3. 2400rms to it. I am going to build a new box for it. It will be 35" wide up to 20" tall and up to 20" deep. I have 3 4" aeroports. And a lot of questions. Car is daily driver, non competition. Plan to tune to 33hz, good freq and fs of driver. I plan on, but don't have to, face ports and sub up (don't want to beat the hatch open) . I have termpro and can figure fb and vb, and have built a lot of boxes but now I have a few questions.

questions:
slot port (if slot how big? 5x12?) vs 3 4" aero ports
Should the port(s) be close to the sub? Or sub on one side, ports on other?
What size box? 4ft? 5ft? could be 6ft. how much is too much when ported?

Thanks
Jim

[F150Matt]

Using three 4 '' aeroports is not gonna really give you enough port area. I would go with around 80 square inches of port area with that 15. If its a daily box I'd go about 4.5-5cubes after displacement of port and woofer, and your tuning of 33hz should be nice for some SQL. I use 3.5 cubes after displacement tuned to 35hz for my XXX 12 with 45 square inches of port(too small but haven't had time to rebuild this box). My competition box that I'm putting up a 148.9 legal with is a lil over 6 cubes after displacements and will soon be going from 121 to 150 square inches of port tuned to about 60hz(haven't decided exactly where to tune yet I'm still playing with the vehicle). Hopefully that gives you an idea of where to start. Good luck man.

[tyranis]

****, what do you have in the competition box?
Any thoughts on where to place the port? near sub or sub on left, port on right, sub in middle, port on right, etc.

thanks a lot
Jim

[F150Matt]

You'll have to play with placement, the easiest thing to do would probably be fire port and sub up. If you decide to go both rear firing or sub up port back, make sure you leave space between the port and hatch equal to or preferably greater than the smallest dimension of your port. Generally if sub and port are on same plane of the box put the port as far away from the sub as possible. My sub is on the passenger side(where the mic is) and port is closer to driver side. Email me if you need more information or any help. hotshot2003@cox.net