I have run 2 12" jl w3v2 d2's for about 6 yrs now. I found that a box that is 1.4cu ft per sub is ideal. Google "Re audio box calculator" and apply the dementions that work best with you space. Also rememember to allow for the thickness of the baffle by adjusting your frequency a little lower than what you actually want it tuned to.

Hey,, i just bought the subs myself and was looking for the same thing as you are,, i looked at the jl audio homepage top see if i could find some awnsers but i couldnt even find the speakers there much less any type of dimension chart,, so i e-mailed their tech support and if it turns up anything ill forward what ive found,, and 1 cubic foot is not enough not for these youll end up overheating the voice coil for sure.. but id highly reccomend doing a series bridge at 300 watts X4 ohms for the best bass range w these speakers!!

Typically you use one cubic foot per sub, so a 2 cubic foot box will work fine. To build a basic one, just a rectangular box, using 3/4" MDF (excellent material for a box), cut pieces this way:

2 - 25.5" x 13.5"
2 - 25.5" x 12"
2 - 12" x 12"

This will give you an interior volume of exactly 2 cubic feet. Cut your sub holes out of one of the 25.5" x 13.5" pieces.