DIY Custom Truck Under Seat Subwoofer Box Build for under $50

Building a custom Sub Box for my 2019 Ford F-150 Truck. I was able to build this box for under $50 by helping a friend build one at the same time and sharing the costs of the materials that could be used to build both boxes. Feel free to use my design and/or apply what you learn in this video to modify this box to fit your make/model truck. Thanks for watching!
Some of the links provided may be affiliate links and the use of these links could result in a small commission at "No Extra Cost To You". Thanks for your support!
Most Tools and Materials I used can be purchased from your local hardware and automotive stores. You may also use the links below to purchase online.
Materials:
Screws - amzn.to/3DRFUST
Liquid Nails Extreme Heavy Duty - amzn.to/3TXJ5hj
Silicone Caulk - amzn.to/3DQpeek
Automotive Carpet - amzn.to/3FBvSXo
Carpet Adhesive Spray - amzn.to/3FAREdN
Tools:
Dewalt Table Saw - amzn.to/3DRmJZh
MilesCraft Circle Guide Kit - amzn.to/3U6AIzM
Dewalt Cordless Drill/Driver - amzn.to/3NocEpY
Plunge Router (I used Porter Cable plunge router for this project however I plan on getting a Dewalt Plunge Router in the future) - amzn.to/3UdrSAj
Dewalt Jigsaw - amzn.to/3E0IiqB
Dewalt Wood Clamps - amzn.to/3NxB3JO
Dewalt Bit Sets - amzn.to/3DRbYWZ

[@chaseyeager5840]

Rockford Fosgate always build the best of everything.. I been doing car audio since I was 16years old now I'm 50 years still love loud music ahhhhhh

[@Vallenge]

Agreed. I've always liked fosgates as well. I'm not far off 50 myself and know what you mean. Thanks for the comment.

[@johnnycorn7225]

46and same here!! About to quit my job because im building so many boxes for everybody now

[@jeffreywhite7657]

I want to be buddy's too lol. I have been shopping for the perfect box and you got it! Got the same truck and now I need the box. Exactly what I was looking for.

[@Vallenge]

Great Comment! Thanks man.... Let me know how it turns out for you...

[@dbwiskus]

Exact video ive been looking for. Have a 2018 raptor with sealed box. Now im going to build a ported box. Thanks for the info!!

[@Vallenge]

Thank you!

[@krisbowers9647]

I watched this video and made mine and it works perfectly. Great DIY sub box for cheap.

[@Vallenge]

Thanks Kris. I'm glad you were able to use this design and make a quality box at a really great price. It's a fun DIY project.

[@eddieb.1901]

Great video 👍great tools great box

[@Vallenge]

Thank you

[@cbinny1]

Great build and thanks for the step-by-step. Now to find one for my 06 F150 lol

[@Vallenge]

Hopefully with a little modification it will work for you...

[@johnnycorn7225]

Slot loading that sub that way will improve cone strength and back pressure on the port while making it bottom out lower as well great build!!

[@Vallenge]

Thank you!

[@theejoeylee]

I've been building a speaker enclosures since the early 90s .I don't know why people insist on using construction adhesive. you should really just use plain old wood glue. the wood will break before the joint will. Now to fill in voids after everything is glued.... then maybe use some PL or something but I would still just mix sawdust with wood glue, and use that because it's almost as tough as wood itself

[@Vallenge]

Thanks for the info Joe.

[@theejoeylee]

@@Vallenge No problem man! Really love the design. Great way to maximize airspace.

[@Alkatross]

Maybe construction adhesive is all some people are familiar with. I use tite bond iii. That stuff is indestructible. The mdf itself would become the weakest link.

[@andrewparker4542]

Sick design! Awesome looking! 👍🏻

[@Vallenge]

Thank you!

[@Alkatross]

With the wedge shape of the box that port is technically a horn.

[@Vallenge]

Thanks for the info.

[@DavidrKun]

The best, dog space right next to the bass. Now that's a Dog Life

[@Vallenge]

Agreed! Lol...

[@bobirdieboberto2752]

Good Work GREAT Job Watch Baby Step Television

[@Vallenge]

Thanks Bo!

[@mmatalk3817]

Poly fill? "The sound wave coming off the back of your subwoofer reacts with the air contained in the box. Polyester fiber stuffing slows down sound waves inside the box, making the subwoofer perform as if the box were bigger. Use 1 to 1-1/2 pounds of stuffing per cubic foot of box volume".

[@Vallenge]

Thanks for the comment. That is another option worth looking at.

[@theejoeylee]

Polyfill has been shown to only raise the low end by .5DB...and that's ONLY below 30hz! Not worth it. 1DB by definition is the smallest increase we humans can detect

[@Vallenge]

Thanks Joe.

[@RandoManFPV]

Where I'm from 1 sheet of 3/4inch MDF is 80$ and a 40mile drive

[@Vallenge]

That's unfortunate. I think prices have about doubled from the time I made the video and of course as I said in the video I was able to split the costs with a buddy as one sheet makes two boxes.

[@RandoManFPV]

@@Vallenge I didn't watch the video I just clicked to share what it's like around here rn haha. Hey full box with one sheet thats pretty good design bro 👌

[@Vallenge]

Thank you.

[@rozzbourn3653]

i wonder if that port calculator subtracks the volume of the port from the overall volume of the box.

[@Vallenge]

That's a good question. I would look for details or tips on the port calculator website you are using and also as you make modifications to the box or port dimensions see if the volume of the box is changing. You can always double check manually by calculating your total box size and calculating your port size and subjecting it yourself to know exactly how much volume you have with your box...

[@mikem.2553]

Great but how does it sound?

[@Vallenge]

Hi Michael. I think it turned out well and I really like the sound. I posted another video of doing the audio install and recording the sound. It's in the F150 playlist and here's the link to it directly kzbin.info/www/bejne/bH2bkHWkd6ilpZY. Hopefully it will give you an idea, it's hard to really know when your not listening to it in person. Thanks for commenting.

[@mikem.2553]

@@Vallenge Awesome, thank you for the link, I will check it out.

[@FriendofFitness]

I wish I could get some help on figuring out my appropriate box size. I recently purchased 2- ct sounds tropo series 8" subs. I want a box like this for my 2007 nissan frontier king cab and I want it ported. I can build anything, but I need a design to specs. I've played with several programs but don't think I am coming up with the right details. Any help from anyone would be so appreciated.

[@Vallenge]

I hear you. It took a little time to design mine as well. Just figured out the space needed and then made biggest dimensions that would fit...

[@armandohernandez9443]

Do you have the video of the install?

[@Vallenge]

Hello Armando. Hope this helps! kzbin.info/www/bejne/bH2bkHWkd6ilpZY

[@javiernaranjo6506]

Hello bro

[@Vallenge]

👋

[@jonathankidd5594]

How would you modify for a 12?

[@Vallenge]

It depends on the specs needed for the 12" sub. I would start off by determining where there is room for the speaker itself to be oriented. Then I would create the shape of the box to maximize the available space. Lastly if you can't make it big enough for the specs of the sub with the space you have you may need to add some sort of filler in the box. Hope this helps. Good luck.

[@ah4800]

No way that port is long enough for proper tuning

[@Vallenge]

It worked for my setup

[@ah4800]

@@Vallenge what was it tuned to?

[@Vallenge]

I used the recommendations of the sub woofer manufacturer and entered data into a calculator and then modified specs to get to as close to ideal at possible for my space. I don't remember the exact tuning numbers but if you follow that procedure you should be able to get good sound...

[@ah4800]

It's gotta be tuned to like 60hz or something crazy with that small of a port

[@bigeasy2187]

you can cheat the size by using polyfill

[@Vallenge]

Thanks for the comment. That is true. I have wondered if by doing that if you get the same results or if there is a difference in the quality of the output.

[@bigeasy2187]

@@Vallenge no it doesn't affect quality. IV been in car audio since 1996 and used that trick a few times

[@Vallenge]

Thanks for the info.

[@swbari00]

Looks nice! I may have missed it but did you subtract the port volume from your measurements as well?

[@Vallenge]

Hello. Yes I subtracted the additional interior wall that I added to create the port to achieve the appropriate port to volume ratio. Great question.

[@LILTiTiAn93]

was this in an extended or crew cab?

[@Vallenge]

The truck this was installed in is a 4dr crew cab.

[@eric4847]

What’s the full dimensions of your build exterior and interior. I really like your set up and thinking I need one for my 2010 F150 Fx4

[@Vallenge]

Hello Eric. I appreciate the positive feedback. The dimensions for my box are 34 1/4" x 12" x 8". You will most likely need to make some small adjustments to your dimensions. It was a fun build and if you decide to build yours let me know how it goes.

[@emmanuelhuggins5302]

If the box is 24 inches how long should the port hole be

[@Vallenge]

You need all the dimensions, not just the length. You can input all the dimensions into the website I referenced to help you determine what size port you need for your particular set up.

[@ah4800]

I have a similar box only its 53 inches long. To get tuning in the low 30s my port had to be 30 inches long. How did you get proper tuning with such a short port.

[@Vallenge]

Use a website that calculates how much cubic inches your port should be for your setup. Then adjust your width length and height to get as close to that as possible with your space. If you have to shorten the length and increase the width to get closer to the measurement needed and still fit I would try that.

[@ah4800]

​@@Vallenge12-16 square inches per cubic foot of air space is the standard. Length will determine the tuning after that. That box you have there can't be tuned properly. If it is ill eat my phone.

[@Vallenge]

Thanks for all the information AH. I used the recommended specs and tunning as my guide to get as close as possible with the space I had and it is working really well for me. I hope you get yours dialed in the way you like.

[@ToniLixSim]

wrong, definitely i have to make and video to tell other how to build and how to not buil, wrong placed and space.

[@Vallenge]

Hi Drift. Let me know when you do so I can watch it. I'm happy with this build but always open to learning and improving.

[@ToniLixSim]

@@Vallenge yeah im goin to do that and will coment here, because people do small box that it needs, and bass go out too fast or it called short bass is other thing bass when go out like bup bup than buuum buum buum hahahhaha 🤣 and other things are speaker need space around, many people do not give that space.. i will make an video about that and comment here to u

[@davidcoronado6346]

Wen its being stretched and used🥲 for music. I should of joined band

[@Vallenge]

👍