How To Build A Subwoofer Box To Specifications

When it comes to subwoofers, there are no two ways about it; they are expensive. But as an integral part of a sound system and a way to up your bass, many of us find ourselves shopping around, counting our pennies, or fighting on Black Friday for the best deal.

Or, we find out that we can save ourselves some money by building the subwoofer box! You buy the internal component, build the box housing it yourself, save yourself money, and give yourself a unique and customized subwoofer box.

But these boxes aren’t without their challenges! They need to be built to your subwoofer’s specifications, leaving many of you unsure where to turn and what to do. You stand there, subwoofer in one hand, wood in the other, clueless. 

Well, no more! I am here to take those worries away and lay out an easy-to-follow guide to show you how to build a subwoofer box to specifications. Let’s get into it!

How to build a subwoofer box to specifications

When building your subwoofer box, the design and planning of it are essential. This needs to be done correctly; otherwise, your subwoofer will not work properly. When you purchase your woofer, it will come with the manufacturer’s specifications about the box it should be housed in. 

You must follow these. Your box’s internal volume needs to match your manufacturer’s specifications for the best results. Often there will be a range of recommended volumes. Ideally, you want your box to be within that range. 

I aim to be in the middle of the range, but that isn’t overly necessary. You need to be in the range, though; otherwise, your subwoofer will not perform as it should. 

Use the measurements to calculate the width, depth, and height your box should be. When making it, ensure your measurements are correct to ensure a successful result. 

Building the subwoofer box

You can use our 11 steps below to build your subwoofer. 

Step 1

To begin, measure and cut the main pieces of MDF for the sides, back, front, and top of the box. You can use a table saw with a carbide-tipped blade or a circular saw. You will need to be careful to keep your cuts square, smooth and flat for best results. 

If you want the front to be thicker, cut two pieces for the front. 

Step 2

Next, take a compass or template to mark the woofers cut out on one of the front pieces. Trace this with a pencil so you can follow the markings later. 

Step 3

For those two panels for the front (it’s recommended for a strong and non-resonant mounting surface), fasten the two front pieces together. Use liberal amounts of carpenters glue and sheet metal screws to do this. 

If you aren’t doing double thickness, plan a bracing elsewhere to give the box added strength. Popular choices are 2×2 inch strips of lumber that can be glued and screwed along two of your boxes’ internal seams. 

Step 4

Use a drill press to make a hole near the inside edge of the circle you traced earlier. You want it large enough to fit your jigsaw blade. You can use a handheld drill and a large bit if you don’t have a drill press. 

Cut out the circle with a jigsaw to give you the opening for the woofer. 

Step 5

Use the same drilling procedure to make a rectangular hole in the box’s back panel for the terminal cup. 

Install this next by running a silicone caulk around the edge of the terminal clamp. Follow with ½ inch sheet metal screws to secure it in place. 

Step 6

It’s time to fasten everything together! The largest sides should overlap the smaller sides to provide more strength—pre-drill holes for each screw. Once drilled, squeeze carpenters glue between the pieces; it’s this glue that seals the box, so apply liberally.

Step 7

Fasten the pieces together using a drill. I used a cordless drill with 2-inch drywall screws, but you can use any drill you have to hand. If any glue squeezes out, wipe it with a wet rag on the outside of the box. You can leave any excess glue on the inside edges. 

Put together the front, back, and sides. The box might be a little out of place; it’s common, so don’t panic! It should all align when you screw the top or bottom on. You can also use furniture clamps to help straighten it if you are having trouble. 

Step 8

Carefully drop the subwoofer in to make sure it fits. The fit might be a bit tight if the box is a bit out of square, but you can use sandpaper to rasp or enlarge the opening slightly. 

Step 9

Now the subwoofer is in place, take a pencil to mark the screw holes. Remove the subwoofer and pre-drilled holes, and place them in the mounting screws.

Step 10

To ensure everything is sealed, wait for the glue to dry fully. Next, run some silicone caulk over the box’s internal seals. Leave it to cure for 12-14 hours before putting the subwoofer back in. 

You must wait as some caulk can release acetic acid fumes when curing, which can harm your subwoofer. 

Step 11 

Once the caulk has cured, you can hook the speaker wires from the terminal cup to the subwoofer. Place the subwoofer back in the box and use non-hardening rope caulk to seal it down. 

And then you are done! You can hook the box up to your sound system or customize the design of the box. 

Final word 

And just like that, we have come to the end of our subwoofer-building journey today! As you can see, building a subwoofer box isn’t too difficult, providing you closely follow the specifications of your subwoofer. You can find this information from the manufacturer and use it to shape the design of your box. 

Remember to take care of measuring and cutting your pieces and ensuring you follow our steps to create a subwoofer box that will deliver outstanding results.

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