FIBERGLASS SPEAKER BOX MOLDED INTO SPARE TIRE WELL
This was not difficult to build, but it took a lot longer and a lot more material than I had planned.
VOLUME CALCULATIONS
I knew that i wanted the subwoofer and amp to be completely concealed under the hatch area carpet. This meant having a recessed area down into the tire well to mount the amp and capacitor. Since I decided on a sealed enclosure, this also meant a loss of volume for the speaker to use. Just by eyeballing it, I figured I could only fit one 12" in that space. I did some rough calculations basing the shape on a cylinder:
Spare Tire Well Dimensions
Diameter = 26" => Radius =13"
Height: 7"
Convert to Feet:
R = 13" / 12 = 1.083 feet
H = 7" / 12 = 0.5833 feet
Volume of a Cylinder = PI * R^2 *H
V = 2.15 cubic feet
I had stereo equipment laying around which I was going to use, and the JL Audio 12" that I had needs 1.5 cubic feet, so I had some room to spare.
I wanted to make sure it was sealed properly, so I used:
48 square feet of cloth - 3M Fiberglass Cloth
2 gallons of resin - 3M Bondo Fiberglass Resin
1/2" Medium Density Fiberboard - 1508108
6 Tubes of Extreme Heavy Duty Liquid Nails - LN-907
Finishing Touches
Carpet - Polymat Felt Carpet
Carpet Adhesive - 3M High Strength 90
Speaker Grille - 12" Mesh Guard with Clips
Speaker Terminals - Dual Speaker Terminal Binding Post
I bought the speaker terminals online, and I wasn't sure of the dimensions. The terminal wasn't long enough to get through the 1/2" MDF, so I had to countersink the area around the terminal.
Carpet Adhesive - 3M High Strength 90
Speaker Grille - 12" Mesh Guard with Clips
Speaker Terminals - Dual Speaker Terminal Binding Post
I bought the speaker terminals online, and I wasn't sure of the dimensions. The terminal wasn't long enough to get through the 1/2" MDF, so I had to countersink the area around the terminal.
SETUP
8 ohm more stable