Here's a write up on how I built a fiberglass box
for two Image Dynamics ID8v3's in the spare tire well for a 2000
Civic Si.
The challenge was to get some sub-bass in the car without losing ANY
trunk space, and without sacrificing the spare tire.
Depth and box volume were the two most difficult challenges. After
some measuring, I found 0.7 cubic feet between the spare tire and
the rear of the car. The jack was relocated to inside the spare tire
itself.
Here's what I had to start with:
The first thing I did was use masking tape to both form the mold and
to protect the car. Always mask more then you think you will need -
fiberglassing is very messy!!
The tape was then sprayed with a few layers of PVA to act as a
release agent:
Next, I prepared both fiberglass cloth and knytex - a cloth/matt
hybrid - it's my favorite material for glassing:
Add some resin, 3 layers of glass, a few disposable paint brushes
and a little MDF to shape up the notch around the brace for the jack
and you get this:
The box was notched to allow it to be easily removed. The next step
was to remove the mold after it had plenty of time to cure. The mold
was then trimmed up, and a piece of 1/2" mdf was cut to act as a
mounting flange for the baffle. The flange was attached to the box
with fiberglass reinforced filler (Dynaglas). You can also see the
underside of the MDF baffle that was created from two pieces of 1/2
MDF:
With the baffle glued, screwed, and caulked, approximately 80% or
more of the baffle was 1" thick - solid as a rock!
Here is one woofer test fitted into the box. You can also see the
trim ring that I routed out to cover all of the mounting hardware.
You can also see the stepped design of the baffle that allows it to
fit under the factory trim:
Some carpet later:
The box was coated in a milkshake before the subs were added. This
was a mixture of resin and cab-o-sil filler. It sealed the box
against any possible airleaks.
The trim rings were chamfered on the inside diameter to give them a
nice touch, were sealed, then sprayed gloss black:
Here's the box in its new home:
The box fits perfectly under the factory floor. The subs were
recessed to allow plenty of room so that the surround will not rub
during use.
This design not only maintains 100% of the utility of the trunk, but
it also maintains the spare tire well.
Because the well is off-center, I built the box so that the subs
would be centered on the trunk. This would allow Eric (the end user)
to customize his trunk with a false floor if he wanted without
having to rebuild the box. Had I centered the subs on the well, he
wouldn't have this option.
How does it sound? Well, with 300w of power, I must say that this
little box was very impressive!
Since most people are interested, total weight was around 35 lbs
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