Hardest hitting subwoofer enclosure I’ve ever made (w/ design image and cut list)

[Optimus Bronco]

Howdy everyone, thought I would share my month-long project. The minute I drove my ‘22 Wildtrak 2-Door home I noticed how poor the sound was. Being that music is part of my life and how important good sound is to me, I resolved to upgrade the base stereo.

I started with replacing all six factory speakers with top-of-the-line Kicker components. Then I purchased a T harness and loop back system from LLJ customs. The T harness plugs into the head unit, goes out to an Audiocontrol D-5.1300 amplifier then routes back to the T harness, and on to the speakers. I took the seat out, removed the inch of carpet and nestled the amplifier in that spot, using vibration dampening bolts. I ran four gauge wire from the battery and hooked everything up. Then I ran 10 gauge speaker wire to the back.

First of all, the sound of the new speakers without the amplifier isn’t bad I have to admit. However, once I looped it through the amplifier and back to the speakers, I knew I had done the right thing. The sound is much more clear and precise. I would say easily 100 times better. I can crank the volume up to 25 without distortion. Crystal clear. It also solves any question about whether the rear speakers are getting enough power. I can’t tell you how much better it sounds.

Now for the fun part, the subwoofer enclosure. I spent a couple of weeks designing this enclosure using Tinkercad, and I decided to go with half inch birch plywood instead of three-quarter inch MDF. I knew the MDF was best, but I wanted to see what kind of performance the half inch birch would give me and at the same time yield an enclosure half the weight.

Why did I design this particular enclosure? I didn’t want a typical box taking up much vertical space, nor did I want something someone could look into the window and see a subwoofer to steal. Therefore, I decided to go with the down firing design. The challenge was to keep the enclosure around the same height as the seats when folded down and at the same time, find a shallow mount sub that would accommodate this while ensuring there is enough clearance for the sub and the airflow coming out the bottom.

After a couple of weeks of design, I settled on what you see. I put it together, using wood glue, screws, liquid nails, and special gaskets to seal up a 12 inch sub. I decided to go with JL Audio’s TW3 12 inch, wired it down to 2 ohm. I followed their recommendations of .8 ft.³ of volume, by giving it .9 then subtracted the volume of the braces and sub itself. Science. I found self-adhesive color-matching carpet for the enclosure, wrapped it up and was astonished at how well it fit. Of course I measured a million times and is a reason why it fit like a glove. The open slots on each side are simply for storage and have nothing to do with the sound.

The results? Crystal clear bass. Turn it up to level 5 and you have a perfect balance and blend of sound filling the cabin, but turn it up to 15 or more, you feel the air pressure moving you. My neighbor two streets could hear it!! Country songs kick extremely hard and tight while hip-hop literally feels like air is being sucked out of your lungs. I’ve never had such amazing acoustical success, but I guess in a two door bronco, one can expect such things. I honestly didn’t expect anything near the power and the feel, it’s really amazing.

Thanks for your time!

Here's the design, and cut list.

PDF File: https://www.bronco6g.com/forum/attachments/bronco-box-12-jl-audio-12tw3-d4-pdf.453622/

Costs:

Amp - $1200
Harness - $150
Speakers - $350
Sub - $425
Enclosure & Carpet - $100
Misc Wiring & Tools - $100

Looks awesome!!

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[Southside_Ray]

I hope one day someone sells something awesome like this for people who live in apartments and can't make these things

Great build!

 

[Sandbergo]

That depends on your level of motivation. If you swap to a smaller in-line muffler upstream, you suddenly have tons of room under the cargo area Great build, OP!

Any specs on that JL Stealthbox? I like OP's design but the 2-door hurts for space and Ford wasted plenty of it behind the trim panels so I do like the idea of tucking one in there.

The last I heard from JL was that they had a two door in and were checking the fit, it has a single 10TW1 and it goes where the factory sub is located. He also stated that it would likely be a month or two before it comes out for sale so likely March.

 

[Rusty Sheckelford]

I plan to bolt it somehow to the rear seat, via a hinge of some sort. Still want to access the storage compartment.

I've been debating a similar style enclosure, and attaching some heavy duty trunk struts to make it raisable for accessing that compartment.

 

[22OBX]

Nice work! Similar idea, mine hits hard as well. The rear portion is just a filler that pivots up for access. Almost level with seats down. The rear also serves as a good hideaway when tailgate is closed.

 

[JBMas]

Nicely done, I had a similar box built for my down firing sub. My audio guys did some computer calculations way beyond my understanding for optimal sub enclosure dimensions. My Lux system upgrade including dsp, new amp, front speakers, (rear waiting for new pods), sub leaves my smiling every time I get in! Best mod by far.

 

[margareedaville]

Nice work! Similar idea, mine hits hard as well. The rear portion is just a filler that pivots up for access. Almost level with seats down. The rear also serves as a good hideaway when tailgate is closed.

Very nice!

 

[BroncoAZ]

Looks awesome.

I’m waiting for the Stealthbox as I’m unwilling to give up any space in the already small 2 door. My ARB fridge takes up a sizable amount of the space available with both rear seats removed.

 

[22OBX]

Very nice!

I obviously used 3/4 MDF I had laying around and more manual design and volume calculation, but I think I ended up about 5.5 tall.. Love the cut sheet and visual 3d modeling . Mine high tech was pencil and a pad.. Great work and nice build.

 

[Darrell]

Great build it's folks like you who make life easier for the rest of us that aren't so mechanically inclined. Also, what are the model numbers for the speakers that you replaced? If I'm going to cheat off you I need all your secrets. Hahaha

 

[margareedaville]

Great build it's folks like you who make life easier for the rest of us that aren't so mechanically inclined. Also, what are the model numbers for the speakers that you replaced? If I'm going to cheat off you I need all your secrets. Hahaha

Thanks! Yeah, no problem. I went with two pairs of the Kicker 47KSC404 for dash and rear and Kicker 47KSC6704 for the kick panel from Crutchfield. You could spend a grand on better speakers, but these seem to handle the power from the amp very well. If you're not using an amp, you'll want to buy their bass blockers for those four 4" speakers.

 

[Darrell]

Thanks! Yeah, no problem. I went with two pairs of the Kicker 47KSC404 for dash and rear and Kicker 47KSC6704 for the kick panel from Crutchfield. You could spend a grand on better speakers, but these seem to handle the power from the amp very well. If you're not using an amp, you'll want to buy their bass blockers for those four 4" speakers.

Thanks

 

[Brnzbronc]

Nice job OP, this was the exact sub and box setup I was wanting to do. Thanks for sharing!

 

[jonboy1225]

Nice job! I'm all about minimal intrusion and with the 2dr's uneven floor with seats down, this is perfect

 

[Les Korcala]

Howdy everyone, thought I would share my month-long project. The minute I drove my ‘22 Wildtrak 2-Door home I noticed how poor the sound was. Being that music is part of my life and how important good sound is to me, I resolved to upgrade the base stereo.

I started with replacing all six factory speakers with top-of-the-line Kicker components. Then I purchased a T harness and loop back system from LLJ customs. The T harness plugs into the head unit, goes out to an Audiocontrol D-5.1300 amplifier then routes back to the T harness, and on to the speakers. I took the seat out, removed the inch of carpet and nestled the amplifier in that spot, using vibration dampening bolts. I ran four gauge wire from the battery and hooked everything up. Then I ran 10 gauge speaker wire to the back.

First of all, the sound of the new speakers without the amplifier isn’t bad I have to admit. However, once I looped it through the amplifier and back to the speakers, I knew I had done the right thing. The sound is much more clear and precise. I would say easily 100 times better. I can crank the volume up to 25 without distortion. Crystal clear. It also solves any question about whether the rear speakers are getting enough power. I can’t tell you how much better it sounds.

Now for the fun part, the subwoofer enclosure. I spent a couple of weeks designing this enclosure using Tinkercad, and I decided to go with half inch birch plywood instead of three-quarter inch MDF. I knew the MDF was best, but I wanted to see what kind of performance the half inch birch would give me and at the same time yield an enclosure half the weight.

Why did I design this particular enclosure? I didn’t want a typical box taking up much vertical space, nor did I want something someone could look into the window and see a subwoofer to steal. Therefore, I decided to go with the down firing design. The challenge was to keep the enclosure around the same height as the seats when folded down and at the same time, find a shallow mount sub that would accommodate this while ensuring there is enough clearance for the sub and the airflow coming out the bottom.

After a couple of weeks of design, I settled on what you see. I put it together, using wood glue, screws, liquid nails, and special gaskets to seal up a 12 inch sub. I decided to go with JL Audio’s TW3 12 inch, wired it down to 2 ohm. I followed their recommendations of .8 ft.³ of volume, by giving it .9 then subtracted the volume of the braces and sub itself. Science. I found self-adhesive color-matching carpet for the enclosure, wrapped it up and was astonished at how well it fit. Of course I measured a million times and is a reason why it fit like a glove. The open slots on each side are simply for storage and have nothing to do with the sound.

The results? Crystal clear bass. Turn it up to level 5 and you have a perfect balance and blend of sound filling the cabin, but turn it up to 15 or more, you feel the air pressure moving you. My neighbor two streets could hear it!! Country songs kick extremely hard and tight while hip-hop literally feels like air is being sucked out of your lungs. I’ve never had such amazing acoustical success, but I guess in a two door bronco, one can expect such things. I honestly didn’t expect anything near the power and the feel, it’s really amazing.

Thanks for your time!

Here's the design, and cut list.

PDF File: https://www.bronco6g.com/forum/attachments/bronco-box-12-jl-audio-12tw3-d4-pdf.453622/

Costs:

Amp - $1200
Harness - $150
Speakers - $350
Sub - $425
Enclosure & Carpet - $100
Misc Wiring & Tools - $100

Awesome build ! And thanks so much for taking time and sharing Your project.
I have question , I am about to start building my sound system
I have JL 10W 3v 3-4 single 10” I would love to use and pair up with Jl JX 500 sub am
would love to use exact footprint. Do you think 10” sub would be appropriate fit acoustically in cubic feet of sound space in your footprint or perhaps I would have to adjust and build smaller ?
I have LC 6- 1200 Ausio Control amp plus sub amp that I would love to mount in same floor space since they are bit bigger. I think that would work very well.
also did you use bolts to mount it all directly to the floor of Bronco.
thanks fir your time and help in this .
for the speakers I will be using Milike legends Herts , Rainbow mids and Audison tweeters

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