Low Profile 12" Subwoofer Box

Being a fan of having music on in the background while I'm working and wanting some of the bass often missed when just listening over mids I built a small sub woofer box for my garage. I had limited space but wanted the range of a 12" sub woofer so I designed a built a low profile box, it can't hold a very powerful sub to do the low air volume but its great for what I wanted. Below is a quick go through of how I put it together should you want to create one as well. I took quite a few pictures during this build so I will let them do most the talking.

As with all projects planning ahead will save time and money, also measuring twice or three times and cutting with care will also save you time, money and frustration.

Tools and Supplies

  • 1x - Sheet of 3/4 MDF 2ft x 4ft
  • Table Saw
  • Miter Saw
  • Drill/Driver & Bits
  • Dremel with basic circle cutting attachment
  • Power Sander and Sand Paper (120 grit)


Cut boards per design, ensure all edges are cut at correct angles. Take the time to measure properly and configure tools correctly.

Start putting the box together, I don't have any fancy clamps for angles, usually I just end up wedging it between things with a few standard clamps added for support. I used wood screws and pre drilled each hole with an appropriate side drill bit. Using MDF requires this as it will split when putting a screw horizontally through it. I also used a larger drill bit to counter sink the screws just a little.

I marked up the face using the sub woofer itself as a template for the circle and fit. My dremel is not very powerful so to save it from burning up I cut about half the depth of the MDF (or 1/4 inch in) then flipped it over and cut it from the other side until the circle just fell out. There is very little extra space on or in this box for the sub I currently have, in the future I plan on getting a weaker 12" sub. The stereo I'm using can't push much too it anyway and I don't want to buy, power and make room for an amp.

Attaching the front face was a bit different then the other sides as it did not have enough wood to support drilling and screwing in without risk of it splitting apart. Also its critical this part holds on really well and transfers vibration to the whole box without shaking itself loose. I attached small cut squares to the inside of the box for the face to rest and attach to. It was critical to ensure that they were placed the correct distance from the front and at the correct angles so the face could rest on them evenly and be flush with the front.

I had an extra speaker box (+) & (-) terminal connector from a previous project that I used for this, lined up a place for it on the back and drilled holes. Once attached remove and place it out of the way until later.

Adding glue on the inside to all the seams so it has a good seal then more sanding.

Coving the box with felt, this can be very frustrating but after doing it a few times it ends up a pretty easy, take your time, follow an order of which side goes first and cut slow. Its best of have over buy the amount felt although it can be a bit pricey, it saves you from trying to work your project to fit the sheet just right. Most fabric spray glue gives you time to peal and re-apply if you make mistakes, mine even came with an extra spray nozzle for some reason. I used a mix of standard office supply store scissors and my wife's fabric roller cutter which I had to clean really well afterward. Over spray is a problem so maybe don't do it on the dinning room table like I did without some sort of disposable cover. Be vary careful not to get any glue onto an outside surface of the felt as it can ruin the smooth look.

Hiding the seams is pretty easy too, just cut them as close and straight as you possibly can then smug the seam in a circular patter to 'mix' the fabrics together. You will quickly notice it starting to just look like a solid peace though looking at it closely enough you will probably always be able to find it so often I like to just leave good enough alone on things that will likely never be seen anyway.

Poke a hole and cut out the speaker space in a pie pattern, folding each peace into the box with a little glue to attach.

Re-attached the speaker terminals to the box.

Wire up the speaker correctly based on how its configured, in my case I have a duel voice coil sub woofer which I wired in sequence to use a single connector. I tried to make the wires inside the box neat and secure, I will probably go back later and solder so the connector but zip ties made for a quick solution.

The low profile sub woofer box is complete, though its always good to square up the logo.


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