Subwoofer Enclosure

After some measuring, I decided to build the enclosure out of wood instead of fiberglass for the simple reason that there is plenty of room in the spare tire well and I can control the internal airspace much better using wood. Total internal volume for the subbox is around 2.5 cubic feet, so after factoring in sub displacement, I am left with about 1.2 cubic foot sealed per sub.
Here is the bottom of the enclosure, all the corners braced with as support beam:





Here are the main cables that runs inside of the subbox to the subs, they are 12 gauge:







And here are the cables that go from the outside of the subbox to the amp, a single pair of 8 gauge:





I didn’t trust the rather flimsy connection points on the speaker cup, so I drilled it out and used two bolts and corresponding washers. Lockwashers and nuts to secure the two sides together:





Four thread inserts were installed to mount the terminal cup, thread locker was applied to ensure it would not back out due to vibration:





An insert was put down to secure a ziptie anchor so the cables will not be strained coming out of the box:







Next, an entire box of Focal Blackhole Five sound proofing material was used to line every interior surface of the enclosure. The Five eliminates resonance and standing waves yet is acoustically transparent, meaning they don’t take up enclosure air space:






Here you see the speaker cables bundled and routed inside the enclosure:



Next the enclosure was stuffed with Blackhole Stuff, a much better alternative to polyfil which serves to smoothout the bottom end of the response and further eliminate standing waves, combined the Five and the Stuff is definitely a bit of an overkill…but nothing wrong with that right?



Next the top baffle of the enclosure was made and temporarily attached:





Then began the construction of the spacer baffles that will raise the subs to the level of the amplifiers. I started with a template made out of 1/4 inch plexi cut on a computerized laser cutter:



Then a bunch of matching pieces were routed from that template:



After some careful positioning, two corresponding holes were cut in the top baffle and the stack of plates attached:





Then the top baffle was permenantly secured to the box:



Since I planned for a totally finished amp rack floor, the sides of the subwoofer spacers were wrapped in 3M brushed aluminum wrap to maintain cosmetic consistency, and now the box is ready to go into the car:







The subbox was then attached to the foundational support structure via 8 bolts that go into inserts previously installed:






The top panel where the subwoofer will actually sit on is routed to be 1/8” smaller than the rest of the baffles to account for the thickness of the carpet. Threaded inserts were placed for attachment of the subs:





The piece was then carpeted, The reason why I chose carpet is to prevent buzzing of the trim panel against it.





Since the OEM trunk carpet is slightly lighter than the black carpet I use, it was dyed with SEM for a better cosmetic match, this method is used on every single piece of black carpet in the build:



Front the get go, we planned to use the yet to be released Illusion Audio Carbon XL 12” subwoofer. The Illusion Audio line is being reintroduced into the US by ORCA, they still have their classic front motor subs and speakers, but the XL series sits at the top of the pyramid. The first 200 of these subs will feature neodymium motors, after them, the subs will come with ferrite magnets since the material for the first 200 were purchased before the insane increase in neo pricing. This sub is capable of taking a lot of power, I was told that they will reach their full output with around 2000 watts…a perfect match for the zero 1 powering them. Each sub is dual 2ohm. The folks at ORCA were fantastic, pulling the first two subs off the assembly line to airship to me directly so I can have them in time. So without further explanation, here is the sub. I do not yet know the details of it, but I will share that info once they are officially released. But I love the CF cone…and the fact that this car is the first one in the world to have them installed.









The sub also comes with a trim ring, but our design was built off of a prototype that did not have this feature, and thus the ring will not be used due to space constraints:





Each sub is wired in series to form 2ohm, and then parallel with each other for a final 2ohm impedance load on the zero 1. Here you see the cable connecting the positive of one coil with the negative of the other:



And finally, both subs were wired up and installed into the enclosure: