building false floor box, need air space requirements for sub Options

[Cormudgen]

I am about to undergo building a custom false floor box for my 6th gen hatchback. The sub I am using is a 12" JL w0. I currently have the sub in a factory box it came with from JL. What i would like to do is build a false floor where the actual box is submerged in the spare wheel well. It is about 4" deep. If i could submerge it 4" in the well and only have to build the false floor 2" up I wouldnt lose that much space. That would be ideal cause then I could use 2"x4" to support the false floor and not have to do nearly as much cutting. What I'm wanting to know is how much air space this sub needs and where I can find the info. Also, when building the box part, after screwing in the pieces together should I use some type of caulk as well? and do I need to carpet the whole box, currently I'm only planning on carpeting the whole false floor. When i do this I fully intend to take pics of the whole install procces so maybe I can write up a tutorial for you.

thanks
cormudgen

[Cormudgen]

Actually I was able to find my airpace requirements! But would love an answer to the second part about buliding the box.


"The 12W0 is a potent 12-inch subwoofer designed to extract maximum performance from small to moderate power levels. Highly flexible in its application, this speaker works extremely well in sealed, ported and even bandpass designs.

Nominal Diameter: 12 inches (300 mm)
Continuous Power Handling: 125 Watts
Voice Coil: 1.38" diameter, 6-layer, Kapton former
Available Configurations: 4 ohm or 8 ohm (Single Voice Coil)
Xmax (one-way, linear): 0.34" (8.6 mm)
Sealed Enclosure Range: 1.00-1.75 cu.ft. (28.3-49.5 liters)
Ported Enclosure Range: 1.75-2.75 cu.ft. (49.5-78.0 liters)
VRC™ Technology: YES"

cormudgen

[AudioFreak]

If you build it out of wood use MDF and glue and screw all the joints. If your joints are tight you don't need caulk but it dosen't hurt.

An alternative is several layers of fiberglass mat to coat the wheel well. Make your false floor plate and the risers like you planned but after the wheel well shell is dry attach it to the back of the false floor with more fiberglass mat and resin. Also coating the inside of the box on all the wooden surfaces.

The wood box's volume can be calculated with basic math but the fiberglass isn't so simple. You need to fill the box with water and then measure how much water it can hold to find the volume. Your sub needs 1.0 to 1.75 cu ft of sealed space. That's equal to 6.429 to 13.09 gallons of water. I would put a heavy plastic liner into the wheel well before I started and measure how much volume it holds. It will give you an idea of how much extra space you will need in the riser if any.

You don't need to carpet any of it so if you want to carpet the top only that's fine. But poly stuffing inside the box is a good idea. Just buy a bag of poly pillow stuffing.