Thought I'd share my latest project - a subwoofer enclosure for the spare tire well.
I'm pretty terrible at fiberglassing but it doesn't stop me from trying I've built 4 different enclosures for my car now. The first two were failures, the 3rd was a lockbox sub for behind the driver's seat built in 2006. For that, I used a Kicker 10" Solobaric.
With the lockbox sub, I was never completely satisfied with the sound. It was plenty loud but the space constraints meant a box not optimally sized for the Solobaric. I prefer quality over volume so I knew I'd be revisiting things eventually. Also it seems challenging to have a large driver in an small cabin yet still retain quality. I've always preferred to get the sub out of the passenger compartment and use the car's transfer function.
Using the spare tire well was an appealing solution but I was skeptical about shallow-depth subwoofer sound quality. I'd originally envisioned using the JL 13TW5-3, but recently revisited the idea and found this MB Quart RLP-304 which had good reviews at a fraction of the cost. The 304 is about 3" high, and the tire well is 6" high, leaving plenty of room for the pole venting and a grille. Unlike fitting the lockbox with a larger driver, the total volume of the tire well makes constructing an enclosure that meets the driver volume requirements fairly easy.
Anyway, it was about a 2 week process from start to finish. The results were definitely worth the effort. The frequency response is considerably lower and flatter overall. I may switch to the JL driver down the road (if I find one for the right price) but I'm impressed with the MB Quart price/performance ratio. There is a little body tub resonance which I'm going to try to dial out by EQ but will probably necessitate some acoustical dampening.
So far, the two big rattle points are the jack storage cover and the brake access panel. For years I'd left the screws out of the brake panel after having a couple of them seize in the rivnuts. The panel always stuck itself back in place and never let water in, so replacing the screws was never a concern until now Even at the lowest volumes, it was pretty audible, so I ordered a bag of nylon M5 screws to put the panel back in place without seized screw concerns.
I also left out the backing board to the carpeting. It's kinda warpy anyway and would definitely buzz/rattle. The enclosure and grille are level with the trunk, so with the carpeting installed and volume off, you'd never know this thing was in there.
Attached are a few crappy cellphone pics, more build pics here
Tire-Sub.jpgTire-Sub---Installed.jpg