pancake

Hey guys, here's my step-by-step for how I created this 10" sealed sub enclosure based on the factory unit from a 2012 Unlimited with Infinity:

Finished:



Basic steps if you don't want to read this whole thing:

• Fabricate MDF trim rings for mounting the new sub
• Cut and modify existing box
• Use the "fleece" fiberglass method to create the new enclosure
• Add more fiberglass to the inside of the enclosure
• Sand/Prime/Paint/Plasti-dip
• Enjoy!

Notes:

• This could be modified to fit a 12" sub, but the enclosure volume would have to be increased significantly. This means lengthening the enclosure towards the front of the vehicle.
• Overall time took about 9-12 hours of labor, but could be done faster since I ran into materials problems and had to do a lot of R&D. Overall it took me about a month, because the wife and kids only allow me about an hour of "garage time" per weekend day
• If you are familiar with fiberglass, this is an easy project. If not, it would be a good first time project, but you will have an investment in materials the first time (resin, fiberglass tools, safety equipment).
• This design allows the underfloor cubby area to open and close, you cannot add depth to the design.
• The factory 12v outlet has been retained.
• This is NOT powered by the Infinity system. I used a line out converter/mixer (LCi-2) tapped off of the front speakers to get the signal to a dedicated mono sub (Alpine MRP-m500).

Here's what I started out with:
Stock:



It's not too bad for a stock sub, but if you want to 'feel' the bass...it's trash. It may reproduce bass accurately according to the Infinity engineers, but I wanted to get a little more thump, so out it goes.

This is the subwoofer that I chose, it's a Pioneer 10" Shallow mount (Pioneer TS-SW2501S4). They can be purchased online for about $100. The mounting depth is 3", but I think I could use a sub with up to 4" depth in this design. The main reason I chose this particular sub is because it has a very small volume requirement for a sealed enclosure (.45 cubic feet). Since the factory volume is about .35 cubic feet, this means I don't have to add on too much more for the sub to operate correctly.







Sub Specs:

• 1200 Watts maximum (300 nominal) power handling
• Basalt/carbon fiber reinforced IMPP cone with fiber-woven radial surround
• 4-ohm single voice coil design
• 20 Hz to 290 Hz frequency response with 90 dB sensitivity
• 3-inch mounting depth

After settling on a sub, I needed to calculate the stock enclosure volume. Using water and a vessel with a known volume, I figured that the total volume is about .356 cubic feet. The new sub requires .45 cubic feet minimum in a sealed enclosure, so I knew I only needed a few more cubic inches to make it work.



Next I made a cardboard template to visualize how the overall diameter of the sub will affect my design.



With the prototype design looking good, I cut some trim rings from MDF using a router and circle cutting jig. I designed it so that the sub would mount flush with the finished surface.





Mocking up the trim rings to the enclosure



Calculating my cuts to get the new trim ring to mount flush. This is important so that you can still open and close the rear cubby area.



I cut most of the shape using a heavy-duty soldering iron since my wife yelled at me for waking the kids up when I was using the reciprocating saw





Test fitting:





Here's the fun part - using the "fleece" method to create fiberglass forms. The concept is that you stretch a synthetic fabric over your shape, add some resin to stiffen it up, then add fiberglass for reinforcement. I've used this method on dozens of projects and it works great. You can check out YouTube to see how guys do this for custom sub enclosures.

Step 1 is to use a high quality contact adhesive to attached the fabric to the form.





Once the fabric is taught, you can trim off the excess.





Adding fiberglass resin to add some strength. I prefer West System resins, they offer good flex-to-strength ratio, have excellent low temperature cure times and convenient ratio pumps for accurate mixing. You can find them at your local West Marine boat store or buy online.







NOT PICTURED - adding fiberglass matt to the inside of the enclosure. This is critical for strength since the stretch fabric doesn't really contribute. It's basically there to define the shape, fiberglass must be added to sustain the abuse from a sub. I didn't take pic because both hands were covered in resin and glassmat, didn't want to ruin the iPhone

Starting to sand and fill:



First primer/filler:



This is called an "Indicator Layer". Adding a contrasting primer color allows you to see how far you're going when wet sanding. The indicator layer will reveal any high spots, the other color will show low spots.





Here's the wiring. I re-used the factory rubber pass-through and added a weathertite quick release connector.



4-5 coats of Plasti-Dip, I love this stuff. I considered a dozen different finishing options, but Plasti-Dip seemed to be the best option for replicating the factory interior finish.



Adding some poly-batt stuffing to the enclosure. This is done to "trick" the sub into thinking it is in a slightly larger box. This is due to how the air in the sealed enclosure is compressed and the heat from compression is dissipated. There are a ton of more scientific explanation on this if you search some audiophile websites.



Added some dynamat to the tub for good measure:



Installed and loving it!







I've begun to make molds so that I can make a "v2.0" with a couple improvements, I'll keep you posted.

BioHazard

Nice work!!!

Where did you put your amp?

pancake

Thanks! I mounted everything under the seat- link: https://www.jk-forum.com/forums/jk-e...-build-230153/

BLK07

Really really good job. Now start the fab. Of another one for me.

Sapper12b

you did exactly what I've been wanting to do for over a year now. if this was my build the only thing I would do different is replace the rest of the speakers while I was at it. overall a fantastic modification and I'm extremely jealous.

Antisimplistic

Beautiful work. Thanks for sharing!

tritonman

This is amazing. I cant believe more people haven't posted in this thread. If i knew what the hell i was doing i would be doing this immediately. Hey, umm any chance you are coming near upstate NY anytime soon?

mrlobaloba

This is awesome Great Job looks stock

SCMatt

That's slick - I like it a lot!

tsamptrail

You could sell these to people like me that do not have the patience to do this. AWESOME job!!