Best Subwoofer Box Design for Deep Bass

So you’ve just bought a new subwoofer and you’re wondering what steps you should take to properly mount it in the right enclosure. Good thing for you, we’ve put together this resource – a one-stop-shop, all-inclusive guide to help your choose or build the best subwoofer box for deep bass.

The main purpose of an enclosure is to improve bass response and prevent subwoofer damage from over-excursion.

So, unless you opt for a free air setup (also known as : infinite baffle), building or buying a pre-fabricated box for your subwoofer is a must.

Choosing the best subwoofer box can be a daunting task, and building one can be a challenge, even for experienced users. There’s a ton of things you will need to take into account before making your final selection that will ultimately affect your choice in subwoofer enclosure style.

Asking the following questions will help you narrow down your choices and make a decision.

What’s the size and shape of your subwoofer?

What type of subwoofer will you be using? Some subwoofers are designed to operate in specific enclosure types. (always refer to the manufacturer’s recommendations).

How much room is available in your car and how much are you willing to sacrifice?

How powerful your amp is and what type of crossovers and controls is it featured with?

What type of music do you often listen to? Different box design will sound significantly different (more on that later).

Best Subwoofer Box for Deep Bass — Reviews

The truth is that DIY projects aren’t always easy or cheap, and they often involve technical work that’s best left to the professionals. Building a subwoofer box is no exception. It takes patience, time and a solid understanding of enclosure volumes and other technical terms to construct your own subwoofer box.

If you want to save yourself from the hassle of building an enclosure for your subwoofer and want an “easy off-the-shelf” solution, purchasing a pre-made enclosure is the right choice for you.

1. Atrend E12S

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Atrend E12S

• 11.125 cutout diameter
• 8 inch max mounting depth
• 0.67 inch net volume
• Premium charcoal carpet

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Atrend is a pretty big name in the subwoofer box industry. The company offers a wide selection of enclosures of different types and sizes. Their enclosures seem to be well-liked. They’re well-designed and reasonably-priced for the most part. The BBox E12S is no exception. It’s one of the best subwoofer boxes that Atrend has to offer.

This 12 inch sealed subwoofer enclosure is built to withstand the deepest bass. It’s constructed with 3/4″ MDF panels and comes wrapped with high-grade charcoal carpet to match the interior of most vehicles.

To reduce front panel flex and provide a solid mounting surface, this enclosure is featured with a 1″ thick MDF front baffle.

Unlike most cheaply built enclosures, this Atrend subwoofer box uses Mitered edge construction technique which provides a cleaner finish and a tighter seal. These Milter joints offer around 40% more surface area compared to traditional Butt joints. And as you might already know, more surface area means means a stronger bond.

Additionally, this box uses Dado Joints instead of traditional butt joints. The former allows for unsurpassed shear strength to withstand strong bass output delivered by the hardest hitting subwoofers. Dado joint also offers a precise, high quality fit and finish.

All in all, Atrend BBox E12S offers a good bang for the buck, and it provides a great bump without killing all the storage space.

2. Atrend BBox E12D

Atrend BBox E12D

• 1 inch MDF front baffle
• 3/4 inch MDF construction
• 11 inch cutout diameter
• 13 inch max mounting depth
• Premium charcoal carpet
• Sealed truck enclosure

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If you’re looking to scale up from the Atrend E12S (mentioned above), Atrend has a few other choices available. One of the more popular options available is the E12D.

Atrend BBox E12D is a dual 12 inch sealed subwoofer enclosure. It’s made of thick 3/4″ MDF panels, and has a thick 1″ MDF front baffle which provides a solid mounting surface for the two subwoofers.

With a combination of Miter and Dado construction, this dual sealed enclosure provides unsurpassed build and sound quality compared to traditional box design.

This subwoofer box measures 13″(H) x 30″(W) x 13.75″ (D). It comes wrapped with high quality charcoal carpet which blends perfectly with the the interior of most vehicles.

3. Atrend Bbox 12AME

Atrend Bbox 12AME

• MDF construction with .75 inch speaker face
• Miter & Dado construction with premium carpeted finish
• Spring loaded extra large terminal cups
• Gross cu. Ft. .55 speaker hole cutout 11.12 inch

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The third offering from Atrend falls on the smallest end of the spectrum. That’s the Atrend Bbox 12AME, and it seems to hit the sweet spot for a lot of guys.

In today’s compact vehicles, space for bass is at a premium. So, how do you get decent bass in one of these problem vehicles without sacrificing your precious cargo space? Well, shallow mount subwoofers have become increasingly popular these days.

The enclosure at hand is designed for 12 inch shallow mount subwoofers. With 6.25″ mounting depth, this little enclosure can fit in the tightest locations thanks to its compact design which allows for multiple mounting opportunities.

Similarly to all Atrend subwoofer enclosures, this subwoofer box is made of 3/4″ MDF and has a solid 1 inch MDF front baffle. It features Miter & Dado construction and comes wrapped with premium carpeted finish.

4. Q-power QTW12

Q-power QTW12

• Quantity: 2 Subwoofer Boxes
• Dimensions (L x W x H): 7.5" x 15" x 20"
• Air Space: 0.88 Cubic Feet per Box
• Mounting Depth: 5.5 inches
• 5/8-inch MDF Construction

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Q-power is another brand that offers a wide variety of subwoofer boxes at competitive prices. So, if you’re on a strict-budget and looking for great subwoofer boxes that can get job done without costing an arm and a leg, Q-power QTW12 could be the perfect choice. I mean, think about it: a pair of subwoofer enclosures for less than 50 bucks? That’s a major bargain.

These sealed subwoofer boxes are designed and built for the deepest bass. They’re constructed with solid 5/8-inch MDF construction and are covered with charcoal carpet.

With a mounting depth of 5.5 inches, these enclosures will easily fit under the seat in most vehicles out there.

5. Belva MDFD12

Belva MDFD1

• Stylish durable black carpeting
• High Quality 3/4 inch MDF
• Gold post terminals for clean and easy wiring access
• Lined w/Polyfil (2.46 cu ft Airspace)

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Belva MDFD12 is another great dual subwoofer box for the money. It’s built with superior construction, has great features, and comes with everything you need for deep pass.

This sealed enclosure is designed to house 12 inch subwoofers. It features 2 separate chambers allowing each subwoofer its own air space.

This subwoofer box is constructed with solid 3/4″ MDF, and it comes with polyfill built into the box, making sure your subs perform perfectly.

As with all subwoofer boxes in the market, the Belva MDFD12’s is covered with durable black carpeting, and it’s featured with Gold post terminals for clean and easy wiring access.

Types of Subwoofer Boxes

The type of bass you get from your subwoofer depends greatly on the enclosure it’s mounted in. Different types of boxes will produce different types of bass. Generally speaking, there are three types of subwoofer boxes including: sealed, ported, and bandpass.

Sealed boxes: For deep, precise bass

A sealed enclosure is exactly what it sounds like. An airtight box. It’s best-suited for any music that demands tight, accurate bass.

In this type of enclosure, when the speaker moves, the air does not escape the sealed the box, it only alters the pressure inside it.

Sealed boxes aren’t that complicated to design and build. You only need to calculate the internal volume of the box, which is done with little effort.

Furthermore, to help absorb the stationary waves produced by the back of the subwoofer and yield better results, you just need to stuff the box with sound dampening material.

If you want tight, and accurate bass, a sealed box is the way to go. However, it must be noted that sealed enclosures tend to require more power than a ported box, therefore, using an amplifier with ample wattage is mandatory.

Ported boxes: For forceful bass

Ported boxes (also referred to as vented or bass-reflux) use a vent which is usually cylinder shaped (or rectangle) to increase output at certain frequencies. These enclosures are much more complicated to design and build than their sealed counterparts.

Furthermore, ported boxes can deliver deeper bass response than sealed boxes at any given amplifier wattage, though they need to be much larger than sealed enclosures to accomplish that.

That said, if you want your bass to boom and you want maximum volume in your music, a ported box is your best choice.

Bandpass boxes: Maximum slam

Generally speaking, bandpass boxes are a special type of ported box designed for maximum slam. In bandpass boxes, the driver is mounted inside a dual-chambered box (one sealed, the other ported), with the sound waves coming out from the ported side. The sound that comes out of the port is extra loud within a narrow frequency range.

Bandpass boxes share a lot of the traits of both sealed and ported enclosures. They come in several types including 4th, 6th, and 8th order bandpass. Each of which offers different bass output.

4th order — In this bandpass enclosure type, the subwoofer is mounted in a sealed enclosure, while the other side is placed in a ported enclosure.

6th order — A 6th order bandpass enclosure has both chambers ported.

8th order — An 8th order bandpass enclosure is quite similar to 6th order bandpass enclosure, but it has an additional ported chamber.

What About Infinite Baffle Or Free-Air?

A free-air setup consists of woofers mounted to a board or baffle attached to the rear deck or placed in the trunk against the rear seats. The board makes an airtight seal and turns the entire trunk into an enclosure. It literally isolates sound from the back of the subwoofer, eliminating resonances, and diffraction, and solving the sound cancellation problem of subs without the need for an actual enclosure.

Free-air systems have a flat frequency response and are huge space savers. The lack of a mounting box makes free air subwoofers more convenient to install, but their power handling levels are significantly reduced compared to their boxed counterparts.

It’s worth mentioning that not all subwoofers are designed for free-air use.

Are sealed boxes the best for deep bass?

Well, the short answer is yes. “Sealed” is the best subwoofer box design for deep bass. Sealed enclosures deliver precise and clean sound. The air trapped inside the enclosure acts as a spring, and offers very good cone control.

So, if reproducing music very accurately at a moderate volume is what you’re looking for, a sealed enclosure is the right choice for you.

Sealed box’s roll-off is about 12 db / octave. This is a smooth gradual roll off that gives sealed boxes a very good response curve without excessive peaks in output at certain frequencies.

It’s worth mentioning that there’s some minor differences between a large sealed enclosure and a small sealed one.

Large sealed enclosures

They render a smooth output with deeper bass, but may also limit your sub’s power handling because the cone has less control at lower frequencies. On the other side, too much power at lower frequencies can damage the subwoofer. So you want to avoid overpowering your subwoofer.

Large sealed enclosure deliver a little less “bump” before they roll off in output. They don’t offer much of the punch as a small sealed enclosure but will play lower bass overall.

Small sealed enclosures

Small sealed enclosures deliver a very “tight” and controlled bass. Unlike in large sealed boxes, a subwoofer mounted in small sealed enclosure will be able to handle a ton of power because the enclosure does limit the cone movement at the lower frequencies.

A small sealed box will deliver a little more output, or “bump” as it is called, before it rolls off. Unlike large sealed boxes, small sealed boxes will will start rolling off bass response at a higher frequency.

How to build a sealed subwoofer box

All you need to build a box for your subwoofer is a few basic tools, hardware, and materials, however, there are many things you need to take into account including the speaker’s size, shape, and volume. The mounting location of the enclosure should be taken into consideration as well.

We’ll explain how to design your subwoofer box on paper. Each subwoofer is designed to operate in a specific volume of enclosure. So, getting the math right is crucial for getting the proper volume.

Next, we’ll walk you through how to build a subwoofer box step by step, and share a few tips along the way.

DIY jobs aren’t for everyone, and building a subwoofer box is no exception. It can prove awfully difficult especially for newbies. However, if you know what you’re doing, it’ll be a lot of fun. It might even save you some cash (depending on the tools you have at your disposal in the garage).

If you get through this article and decide that building a box for your subwoofer is not for you, then check out our selection of the best subwoofer boxes for deep bass.

Choosing your subwoofer

Not all subwoofers are built equally. So, when choosing a subwoofer, always pay close attention to the manufacturer’s recommended enclosure size. That’s even more important if you have very limited space in your car.

The box volume dictates how big your enclosure needs to be for maximum performance from the subwoofer.

This brings us to the next step in the process of building a subwoofer box and that’s determining the correct dimensions for your subwoofer box design.

Planning your subwoofer box design

This is the part where getting the math right is crucial for a better overall subwoofer box design.

Step 1: Determine the minimum depth of your box

To determine the minimum depth of your box, you need to measure the depth of your subwoofer and add 2 or 3 inches. The result is the minimum depth of your box.

Step 2: Determine the minimum height and width of your box

To determine the minimum height and width of your box, measure the frame diameter of your woofer or check the sub’s spec sheet. If you intend to use a grille, make sure to take that into account and allow for any additional space that may be needed to accommodate it.

Step 3: Determine the available space in your car.

The available space in your vehicle or the amount of space you’re willing to sacrifice dictates the size of the subwoofer which in turn dictates how big your enclosure needs to be.

That said, measure the height, width, and depth of the vehicle space that you are willing to sacrifice for your subwoofer box.

Step 4: Determine the internal dimensions and volume of your box

Now that you have determined the external dimensions of your box, it’s time to determine the internal dimensions. To do so, subtract the thickness of the wood you’ll be using the build the box from the external dimensions. If you’re using 3/4″ MDF (recommended!), then 2 x 3/4″, or 1-1/2″, will be subtracted from each dimension.

Step 5: Figuring out box volume

To figure out the internal box volume in cubic inches, use this formula:

Cubic Volume (in inches) = Height x Width x Depth

Most manufacturers provide the recommended box volume in cubic feet, therefore, you’ll need to convert the internal volume from cubic inches into cubic feet. This is done by dividing the cubic inches by 1,728.

Step 6: Decide on the dimensions for your subwoofer box’s front panel

This is a crucial step, why? Well, simply because the front panel will hold the subwoofer, therefore, it must be large enough to hold the sub. So, consider adding at least 2 to 3 inches to the size of the subwoofer. For example, a 12 inch sub should have a front panel at least 15 to 16 inches square.

Choosing the Material

Because a subwoofer enclosure needs to be as rigid as possible, it must be built with very dense and heavy wood as any flexing in the enclosure will drastically decrease your subwoofer’ performance.

The pressure inside the enclosure is what determines how rigid the enclosure should be. So, it’s not recommended to make an enclosure housing an 8 inch subwoofer as rigid as another one with 15 inch or dual 12 inch subs.

Having said that, sometimes it’s often more effective to brace the enclosure than to double up the wall thickness. So, remember that both wall thickness AND bracing increase the rigidity of the enclosure.

Using materials such as MDF (medium density fiberboard) or Medite (high density fiberboard) is recommended for building sub boxes. These materials are quite rigid, heavy and not porous like some particle boards.

Furthermore, it must be noted that all of the joints and walls in a subwoofer enclosure should be as airtight as possible, including screw holes and wire holes. Any air leaks will cause cancellation, resulting in reduced output.

Enclosure walls should be mounted using a combination of carpenter’s glue and panhead sheet metal screws. As always, pre-drill and countersink the screw holes to prevent splitting the wood. Using silicone caulk to seal the gaps in the enclosure seams is also mandatory.

You might want to invest in a drill bit which both drills the pilot hole and countersinks the drywall screw head.

Polyester fiber stuffing is also quite important when building a subwoofer enclosure. It’s meant to even out the sound of your subwoofer enclosure, and make the subwoofer perform as if the box was bigger.

Generally speaking, using around 1 to 1-1/2 pounds of stuffing per cubic foot is all what you want.

Step-by-step for building your subwoofer box

Step 1: Measure & Cut the pieces

Start by measuring and cutting the main pieces of MDF for the front, sides, back and top of the box. If you choose to use a double-thickness of MDF for the front panel, consider making an extra piece of MDF.

Step 2: Mark the woofer cutout

Now that the box pieces are ready, use a compass to mark the woofer cutout on one of the front pieces. The circle needs to be big enough to fit your speaker and allow the “lip” hang over so it can be screwed in.

Step 3: Reinforce the box

Doubling the thickness of the front panel is highly recommended. It strengthens the box as a whole and allows for an extremely strong, non-resonant mounting surface for the woofer.

If you decided to go this route, you’ll need to fasten the two identical front pieces together using plenty of carpenter’s glue and several sheet metal screws.

If for some reason, you decided not to use a double thickness of MDF for the mounting surface, you should definitely consider bracing your box, especially if it’s large or if it’s loaded with large powerful subwoofer. The box will have to sustain extreme internal pressure, so the stronger it is, the better.

Bracing a subwoofer box is never a bad idea. One of the easiest ways to add bracing to a subwoofer box is with 2″x2″ strips of lumber. Fasten these along at least two of your box’s internal seams before attaching the top and bottom.

Step 4: Cut the woofer opening

Unless you have router or something better, cutting the circle (woofer opening) is the hardest and most difficult part of building a subwoofer enclosure.

That’s not to say that it can’t be accomplished without a router. Quite honestly, you can use a drill-press to make or a handheld drill to make a small hole near the inside edge of the circle we had marked for our jigsaw blade to fit in.

Step 5: Cut the terminal cup

Basically, the same method can be used to make a rectangular hole in the box’s back panel for holding the terminal cup. So, once the hole is drilled, apply some silicon caulk around the edge of the terminal cup, and mount it into using a few sheet metal screws

Step 6: Assemble the pieces 

With the speaker cutout and the terminal cup mounted, it’s time to fasten everything together. Use plenty of glue between the pieces because it’s what will ultimately seal the box. Some of it will squeeze out when you’re fastening the screws — you can wide it off the outside of the box, but it’s recommended to leave it on the inside (it’ll help with the seal). And you’re almost done.

Step 7: Mount the subwoofer

Now, try to mount the subwoofer in and make sure it fits. If it does, then congratulations! If it doesn’t, use P40-P60 sandpaper grit to slightly enlarge the opening a bit.

Step 8: Mark subwoofer screw holes

Now, drop the subwoofer in and mark the screw hole locations. Next, remove the subwoofer and pre-drill the holes for the mounting screws.

Step 9: Seal joints and internal seals

As a precautionary measure, apply some silicon caulk over all of the box’s internal seals and wait for 12-24 hours to let it dry before putting the subwoofer back in.

Step 10: Run the wires

The only thing left now is to place the woofer back in the box and run the wires from the terminal cup to the subwoofer. And Voila!

Finishing and customizing the subwoofer box

After finishing the box, It’s time for carpeting and adding some finishing touches, since naked MDF leaves a lot to be desired, aesthetically speaking.

The sky’s the limit when it comes to customizing subwoofer enclosures. Instead of carpet or vinyl, any type of fabric can be used for wrapping the box.

Final Thoughts

Following the directions we listed in this article, you should be able to build your own subwoofer box for deep bass.

To make it easier for you to follow these instructions, we converted this webpage into a pdf file you can download.

And if you need help, feel free to contact us with any questions you have. We would love to see how we can help out!