The floor is a little diferent. To utilize the most air space, build a box face. Remove the back wall uppulsrty or linning or panel or whatever. Cover the whole back pannel with alluminum foil. Use card board as a template to make the sides. Make 4 side so that you have center deviders for each chamber. When woofers shair air space they may produce the same SPL DB but I can always hear the turbulence of the rear waves fighting each other. I never build 1 big box! Always give each sub it's own chamber unless the only muzak u like iz rap cuz metal sounds like shit when the subs go "whoomp whoomp".
Now if you do this right you will have a flat piece of at least 1/2 inch MDF comming from the floor from the back of your seat's mounts with the seets all the way back, up to the back waal just below the window. Then you'll have 4 triangle with a notch where th 90' right angle would be for the rise in the floor just in front of the wall. Skrew the 2 sides on and evenly space the 2 center deviders to make 3 identicle sealed chambers. The alluminum foil on the back wall and cover the part of the floor that is "inside" the box is so you can slap in some fiberglass and resin and it won't stick to your truck. Use the thickest matting for strength. This will utilize every square inch behind your seats, offering the most air space for your subs, and look sweet covered in carpet, tweed, leather, vinyl, or whatever. Fiberglass work is EZ but the resin stinks, so make sure you have air! You can use a boat repair kit from Home Depot or Lowes to make alost any sub box shape. I'd build it for you for $100.00 but it would'nt be worth the weight to send it.
