Hello All,
On Saturday I finished installing my new subwoofer. Now this isn't normally a big deal, but there is little space for a sub enclosure in a supra and even less space when you have an aerotop as the roof is stored in the boot. In fact, there is no room in the boot when the roof is stored away in there.
After seeing what Lee (SRD) did with the space in the spare wheel well on Jamie's car, I decided that I'd ditch the spare myself and build an enclosure in there.
Before the sub, I had my rainbow speakers (FL, FR, RL and RR) running from a Kenwood Amp. I decided that I wanted to stick with Rainbow for the speakers and purchased a Rainbow 12" Hammer sub. To power the Sub, I purchased a second Kenwood Amp.
In order to get the required volume in the sub enclosure, I came up with a pretty tricky solution that would provide the required air volume but also be easy to remove if necessary.
The first thing to do was remove the boot trim and the stock subwoofer enclosure:
I used the existing bolt holes to mount a square section of MDF. This will be where the enclosure will be fixed to for stability. As you can see from this picture, the main obstacle in building the enclosure is the hump (technical term!) for the spare wheel, which also houses the fuel pump below.
The first thing I did was construct what would become the new base of my boot space. I did this using a cardboard template to ensure the fit was right before I cut the shape out of the MDF:
Without much margin for error, I cut a hole for the subwoofer to sit in. This area sits above the largest space within the wheel well (bottom left as you look at it from behind the car). I did want to mount it to the top right, but there just wasn't enough room for the 12" sub.
I couldn't afford to build around the hump, as the enclosure wouldn't have the required volume of air, so I decided to utilise it as a wall of the enclosure (sort of).
So I measured and cut what would be the base of my sub enclosure:
Which fitted as so:
Utilising a sheet of 3mm thick rubber, strong adhesive, flexible silicon and 13mm staples from my nail gun, I created this seal that would sit around the hump. When the sub is dropped in to the wheel well and pushed down, the rubber forms tight seal around the hump. Sort of a like the action of putting a jonnie over the helmet
The next step was to construct the rest of the enclosure. Using lengths of MDF I had cut at a local timber merchant (to ensure perfectly straight edges), I constructed the rest of the enclosure:
And this is how the enclosure sat in the wheel well:
I added a terminal box to the side of one of enclosure walls to ensure easy of removal when necessary:
Silicon sealed from the inside:
With the enclosure complete, I placed my new boot floor over the box and transposed the sub hole onto it (the enclosure is slightly larger than the boot floor as it sits underneath the plastic boot trim – again, so it can be removed easily enough when necessary).
This photo shows the sub hole in the enclosure, along with the wiring and the silicon seals around the joins:
And now with the boot floor on:
And the final step was to mount the sub and wire everything up (this was done by my auto electrician).
As my Kenwood head unit has a pre-out for each speaker, everything is controllable via the head unit. So the sub can be turned off and the levels can be altered when it’s on (I’m still trying to get around it all). I’m really pleased with how it turned out. The sub is rather powerful, so I’ve set it changed the gain to something like -7 decibels for general use, which seems to have tamed it to a level where it adds a bit of thump but not enough to p!ss the general public off.