Acrylic Subwoofer Enclosure for Under a Car Seat.




Introduction: Acrylic Subwoofer Enclosure for Under a Car Seat.

About: electrician in pittsburgh.

Hello hello. First off this is my first instruct-able and as such i welcome and questions and comments that come my way and will entertain them as best i can.

My scooby is kinda small ... so space management is a must and was my main concern for this build. This box can built by any novice (like me) with minimal effort and time for around $100 in material (excluding the sub/amp). Enjoy

Things you will need:

1) 1/4" thick {the thicker the better} acrylic or plexi glass
2) quilt batting
3) acrylic glue {i hear acetone from a saloon works also but not sure}
4) silicone
5) fine pointy paint brush
6) 1"- 1.25"self drilling #8 or #10 screws to attach the sub-woofer.
7) duct tape and sand paper
8) jig saw or dremmel
9) sub-woofer and amplifier
10) drill, basic hand tools, and a socket set
11)  table saw or circular saw will make your life much easier
12)i think that's everything... lets get started!

Step 1: Can You Feel.... the Bass?

first do some math and measuring as every car will be different. i have a 2007 Subaru Impreza 2.5i and i came up with an enclosure size of 5and 7/8" total  enclosure height {6.75" tall with sub }  12.5" wide and 14.75" long. 

After you measure find the surface area of the cube with LxWxH for each side (a cube has 6 sides) and go out and procure your acrylic... or lexan... or whatever.

***side note*** i chose acrylic b/c its cheaper than lexan and way better than wood for its size... at least that's what i think i learned from all those forums.

*** fun fact ***  the enclosure is also not supposed to be a symmetrical shape due to re-verb and sound distortion .... something along those lines.... but i have had little if any problems like that with my build.

*** also under my seat i have re routed some cables for the air bag sensor and bent some metal out of the way and gained some extra room***

*** remember to leave height for butt clearance if you ever plan on having a passenger***

Step 2: Its Box Makin Time!

measure out your material and get a game plan so that you can efficiently use the acrylic with little waist... in my mind its not cheap.

***Clean 90 degree cuts are essential for later steps so take your time b/c spending 10 extra min. here will save you hours later***

cut out your squares and rectangles and doo dads and what nots.. do not throw away the little peices of scrap as you can use them to suport your joints when you glue it all up. (note all the long pieces in the back left of the picture)

i had some leftover jacks from my last sub enclosure so i used it... simply whole saw or drill a few small wholes around the perimeter and use the jig saw.
***as seen in the picture.***

now is the time for you to mark up the sub-woofer hole and using the same method drill and cut it out.

*** typically for a 10" sub you need about a 9.75" hole but every sub is different and each manufacturer should have that info somewhere in the instruction book***

Step 3: Making It All Stick.

using sand paper rough up all your pieces where you want to make the bond... i got a little carried away and roughed it all up. at least now it's consistent. haha

my old man had this UV proof lexan bonding magical chemical from his past life as a sign maker... so i used that... im not really sure what it was or where you get the stuff but he also said that acetone from a hair styling place would work for acrylic.

piece together all your pieces one by one ... use this video if you need a crash course. i used the paint brush to apply the weld.

first weld everything up... then go back and add your support strips along the corners for extra strength.       *** this is where i used those long strips ****

***ADDED BONUS! ***i believe these little strips in the corners are the reason i don't have sound distortion.

tape it all up for strength and allow it to cure for a day or two.

after it cured i ran a bead of silicone around all the edges for good measure

Step 4: Tell Me Why Do We Build Castles in the Sky?

the end is in sight. 

use about 3/4 of the quilt batting and fluff it into your box do not pack it in like a folded towel.

the reasoning for the batting is this:

in my mind it is beneficial to use this method b/c the box is already almost undersized for the sub. and i am very happy i did. i tried it with and without stuffing  and preferred it with the poly fill but by all means try it for yourself and do what you think  is best.

Step 5: I'm Your BbBasscreator

Install Mr. Sub-woofer with the self drilling screws very carefully b/c it is very easy to crack the acrylic when doing this.

*** note: if you do manhandle it and you get a crack or two you can always try and seal it up with that magical welding solvent or acetone*** 

(still not entirely convinced about the acetone being effective)

Step 6: I'm Pickin Up Good VVviiBbrations

ok so now you have a complete install like me... but then you realize you just a lot of hard work into an enclosure with a really cheap crappy sub in it....

i could not let this be the end of my project. its sound most certainly did not make me happy. so off to the store i went to get a new sub for my new enclosure and new amp.

i fit the sub into the box and realized it was 1/4 too tall now... so i just whole sawed through the bottom of the box the same size as the magnet and everything turned out just fine... in fact it sounded better now that the box was ported. haha

bolt the seat back on and make sure everything had clearance... i have no clearance now... its a perfect fit.

i put the sub under the passenger seat and the amp under the driver.

*** also if you may like to check out for some good vibrations***

well that's all folks. hope you enjoy your as much as i do mine.

Be the First to Share


    • Puzzles Speed Challenge

      Puzzles Speed Challenge
    • "Can't Touch This" Family Contest

      "Can't Touch This" Family Contest
    • CNC Contest 2020

      CNC Contest 2020

    10 Discussions


    2 years ago

    I have found for working with acrylic to preferably use new bits when drilling, I have had good results with high speed steel bits, but use at low speeds to avoid cracking it from vibrations (ironic). If you have exposed edges that aren't to be glued and want it to look smooth, use MAP gas (yellow bottle) to flash over it GENTLY and quickly. Butane (blue bottle) will not work as it does not burn hot enough. Drill all screw/bolt holes oversized to the depth of the head of the round headed bolts/screws you use before finishing the holes with the desired diameter holes for the shank of the bolts/screws. The reason is if you use countersunk heads, the acrylic is more likely to crack, and with the recessed bolt/screw heads, they will look better and not snag on anything. I use cap screws myself, and try to fit the step cut holes to the screw heads so when inserted they look like they were machined in, and it makes for a very professional looking job. For fine fitting of irregular pieces, I use a brass wire wheel in a bench grinder. It makes fairly clean subtle changes if you practice a bit first. I have even been able to use this method for removing decals, stickers, and other anomalies from the surfaces, but it has to be a brass wire wheel, don't let heat build up, and it will mark the surface really quick if you are not careful.

    There's more tricks, but that's all I can think of right now.


    7 years ago

    Thank you bsodgergren for clarifying. I did not know that. ( obviously ) haha.


    8 years ago on Introduction

    acetone is what you use to clean up the acrylic glue that you inevitably get over every thing.

    you don't use acetone to "glue" or weld acrylic together.

    Acetone is also good for cleaning up fiberglass resin.


    9 years ago on Introduction

    thanks i made one of theas out of mdf and it sounds great when added to my stock system

    How did you cut your acrylic? i tried a couple months ago to make a little speaker for my room and couldnt get straight cuts with a knife or saw... Nice subaru by the way...


    Reply 9 years ago on Introduction

    Sorry it took so long to reply I have not had time for projects in a while. I used a whole saw and a fine tooth jig saw cuz I didn't need it to be a perfect cut for the speaker hole. For the clean cuts I used a table saw at a low blade setting. ... If it is thin acrylic I would suggest using a razor blade knife to score it and then snap it... Practice first on some scrap piecesd


    9 years ago on Introduction

    ahh. well thank you. i love my suby. anyways. i used a table saw to cut most of my acrylic since it was almost 1/4 inch thick. it was very effective ... i also used a hand held jig saw which worked better than expected. thank you for the question. please let me know if i can help with anything else.


    9 years ago on Introduction

    note: it fits way better when you don't switch to a diff. sub after the box is completed because it would fit way better if it was even 1/4" shorter.