Does Car Subwoofer Need A Box Enclosure? (Explained)

In the past, the traditional method for setting up your vehicle’s audio system was by putting your subwoofers in a box.

Today, though, some drivers choose to install the subwoofer sans box.

While this may sound like a “dream come true,” there are a few things to consider before jumping on the “no-box” side of the argument.

Here’s Why A Car Subwoofer Needs A Box Enclosure

Subwoofers are designed to be used in a box. They must have an enclosure to balance the frequencies that are emitted. The sound may be negligible if you try to use a subwoofer without a sealed box.

Table Of Contents

Here's Why A Car Subwoofer Needs A Box Enclosure
Does A Car Subwoofer Require A Box?
What Happens If I Install A Car Subwoofer Without Box?
How Big Does the Subwoofer Box Need to Be?
How To Make A Subwoofer Box for A Car?
What Is The Best Place To Install The Car Subwoofer With The Box?
Do Car Manufacturers Provide Space For Subwoofers?
Getting the Best Sound From Your Subwoofers
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Does A Car Subwoofer Require A Box?

Before installing your car’s subwoofer without a box, you must understand why the enclosure is so important.

This information will help you make an informed decision about how to proceed.

Subwoofers are designed with several components that emit low-frequency audio signals from the back and front of the speaker.

If the speaker isn’t put in a ported or sealed enclosure, the frequencies that are usually cast back into the enclosure are sent in the air and may cancel the sound effect of signals being sent forward.

With a box (or enclosure), the ideal setup for low-frequency audio signals is created.

Put simply; the box provides that deep bass you want (and expect) from a quality subwoofer.

Without a box, the subwoofer can’t perform the way it was designed to, which leaves you with low-quality sound when listening to high-bass music.

Check out this great article on the performance of a car subwoofer.

What Happens If I Install A Car Subwoofer Without Box?

Using a subwoofer without a box is not recommended. Doing so will lead to a subpar sound experience and likely be disappointing.

Without a box, a traditional subwoofer will sound mediocre, at best.

Most people purchase and install subwoofers to provide the deep bass sound that creates the “boom” effect as they drive down the road.

If no box is used, the desired sound will not be created.

The only time using a subwoofer without a box is viable is if you purchase a free air subwoofer. These are specifically designed to work without the otherwise recommended enclosure.

How Big Does the Subwoofer Box Need to Be?

Are you thinking about making an enclosure for your subwoofer? If so, the most critical aspect is the size.

Subwoofers need plenty of space to provide the best sound. Not only will the right size improve the sound quality, but it also means a longer life for your speaker.

A general rule is that the bigger your subwoofer is, the more volume of space you need around it.

The volume space for a 12″ subwoofer is 1.25 cubic feet. For a 10″ subwoofer, the volume should be 0.625 cubic feet.

If you tend to play the music that isn’t “bass-heavy,” then a larger enclosure is recommended. This creates a flatter sound.

Creating a smaller box than recommended, won’t provide adequate acoustics and limit overall sound quality. Your speaker will likely wear out sooner than it should, too.

How To Make A Subwoofer Box for A Car?

You can purchase a pre-made subwoofer box. However, making it can help you save some money and ensure you get the right dimensions for the best sound possible.

If you make your own box, be sure to collect the needed supplies first, which include:

Circular saw table saw, and jigsaw
Electric drill with bits for pre-drilling holes and driving screws
MDF board
Drywall screws
Sheet metal screws
Silicone caulk
Carpenter’s glue
Robe caulk (non-hardening)
Speaker terminal cup

Once you have the needed supplies, you can plan the design of your subwoofer box.

Some steps to help you with this include:

Establish the minimum box depth. To do this, measure your subwoofer’s depth and add two inches.
Establish the height and width of the box. Measure your woofer’s frame diameter or look at the mounting template included in the owner’s manual to find the minimum width and height for the front of your box.
Measure the space in your vehicle. Measure your vehicle’s depth, width, and height (where you plan to install the subwoofer). For some vehicles, a wedge-shaped box is needed. In this case, you need to know the depth of the box at the top and bottom.
Sketch your subwoofer box. Use paper and sketch the box you want to build. Be sure to include the measurements of each side to create a box that will fit.
Figure out the volume and internal dimensions of the box. You need to figure out the internal volume of your box, which is done by subtracting the wood’s thickness. For example, if you use ¾” MDF (which is the recommended option), you subtract 2 x ¾” or 1 to 1 1/2″ from each of your dimensions.

Building your box requires you to use the dimensions found in the steps above. In most cases, the process is straightforward and simple.

The specific steps for building your subwoofer box include:

Measure and cut the main MDF pieces for your box’s sides, bottom, and top.
Mark the woofer cutout on the front MDF board.
For double thicknesses on the front panel (which is recommended for the best sound), fasten the two front pieces together using sheet metal screws and carpenter’s glue.
Cut out the circle for the subwoofer.
Make a rectangular hole in the back panel to hold the terminal cup. Add silicon caulk around the terminal cup’s edge and screw it in place with sheet metal screws.
Fasten the parts together, remembering that MDF is prone to splitting, so having pre-drilled holes for the screws is recommended.
Use glue and drywall screws to fasten everything together.
Line the internal seams with silicone caulk to ensure everything is properly sealed.

Once your box is complete, you can customize it if desired. Many people don’t like the look of MDF, so there are options to consider to make it more aesthetically appealing.

What Is The Best Place To Install The Car Subwoofer With The Box?

There are two main options for installing your subwoofer box, including in the cab or trunk. It’s pretty hard to find other locations that will be able to house the subwoofer in your vehicle.

A trunk is a popular option because you can’t see it. Also, with the box in the trunk, you and your passengers have more space in the cab. Also, with the speaker in the trunk, potential thieves won’t know it is there.

However, for some vehicles, the sound is slightly muffled, especially when the trunk is far away from the driver and passengers.

You will get better sound quality if you place it in the cab.

If you love a rich, clear bass sound, then having the subwoofer in the cab is recommended.

Do Car Manufacturers Provide Space For Subwoofers?

Most car trunks or cargo areas are large enough for subwoofers. However, manufacturers don’t specifically make space for these speakers when designing and building vehicles.

Since vehicles aren’t made for subwoofers specifically, it’s up to you to ensure everything “works” together.

Because of this, you should measure the available space to ensure that the box and speaker you purchase will fit and provide the quality sound you want.

Getting the Best Sound From Your Subwoofers

Not all speakers are created equal and the way they are installed and used impacts the sound you hear.

This is true for all speakers, including subwoofers.

Having a sealed box for your subwoofer will create the best sound possible for your audio experience. You can purchase these boxes pre-made or build one yourself.