The secret to getting your bass to sound just the way you want it is to choose the right type of subwoofer box. Whether you’ve opted for an 8”, 10”, 12”, or 15” subwoofer, the enclosure you put it in plays a major role in the sound performance you get out of it.
In this post, we’ll discuss the three most common types of subwoofer boxes on the market today; sealed, ported, and bandpass.
If you haven’t picked out your amp and sub yet, check out the posts linked below for some guidance on how to pick those out as well.
Sealed Subwoofer Boxes
Tight, accurate bass is the name of the game with sealed boxes. The design of a sealed subwoofer enclosure is just how it sounds, the air chamber behind the subwoofer cone is sealed so that no air moves in or out of the space. The crisp sound is a result of the air inside the enclosure acting like a shock absorber. It workings to push or pull the subwoofer cone back to its resting position.
The simplicity of the sealed box allows for a compact design. If trunk space is an issue, then a sealed box is the way to go. The exact volume of the box will depend on the subwoofer you plan to put in it. A subwoofer’s specifications should indicate how much volume the enclosure should have if you are going to mount it in a sealed box.
One drawback to this box design is the efficiency. It requires more power to produce high bass volume than other subwoofer box designs. But that is a small price to pay for those who want to hear and feel the precise punch of every bass kick in their rock, metal, or country music lineup.
Ported Subwoofer Boxes
Ported boxes are great for loud, boomy bass. The construction of these enclosures is similar to sealed boxes except they are typically larger to accommodate the port. The port is an opening in the subwoofer box with a tube that allows air to move in and out as the subwoofer operates.
The port can be any shape or size but it is typically tuned for a specific frequency range to allow the sound waves emanating from the back of the subwoofer to exit the opening of the port such that they combine with the sound waves from the front of the subwoofer resulting in louder bass.
Since the subwoofer does not have to fight against air pressure, like in a sealed enclosure, ported enclosures tend to be more efficient, requiring less power to produce high volume.
Ported boxes work well for music with big boomy bass where precision is not so important such as rap, hip-hop, R&B, and techno. Music with punchy bass kicks, however, will tend to sound a bit “muddy”.
Bandpass Subwoofer Boxes
Bandpass boxes are sort of a hybrid between sealed and ported enclosures. The subwoofer sits within a dual chamber enclosure. One chamber is sealed and the other is ported.
Since the subwoofer is mounted within the enclosure, the only source of sound is from the port. The port, along with the two chambers, are tuned to amplify the sound from the subwoofer over a specific frequency band…hence the term bandpass.
These subwoofer boxes are meant to really pound out the bass. But before you get super excited about the idea of rattling your door panels off, there are a few things you need to understand about these enclosures.
Things to Consider about Bandpass Subwoofer Boxes
- The sealed chamber volume, ported chamber volume, and the port itself all need to be properly tuned for the box to sound good. Even small miscalculations or sloppy construction can throw the whole thing out of whack.
- A lot of forces are exerted on the subwoofer in a bandpass enclosure. Applying too much power can make the subwoofer literally rip itself apart. And since the box is designed to mask all sound except for the frequency band it is tuned for, you won’t hear the sub crying for help until it is too late.
- Similar to the previous point, the sound of distortion is also masked by the design of the enclosure. So, again, the subwoofer may be crying for help, but those cries are muffled by the enclosure.
- There is no such thing as a universal bandpass box. For starters, not all subwoofers are designed to be used in a bandpass enclosure. Always check the manufacturer’s specs to see if yours is. Additionally, not all subwoofers are created equal. Every make and model will have their own unique sound characteristics that would need to be considered in the design of a bandpass box.
For the beginner audio enthusiasts out there, I would suggest going with a sealed or a ported enclosure. But if after reading this, you are hard set on a bandpass enclosure, here is my advice:
- Find a good quality, pre-loaded enclosure. This means the subwoofer manufacturer has already designed the bandpass box for a specific subwoofer and sells it as a package with the subwoofer pre-mounted in the box.
- Find an experienced box builder to design and build a custom box specifically for the subwoofer you want to use.
Whether you are after crisp, precise bass, or you want the bass in your car to make your hair fly like you’re standing in a stiff breeze; the subwoofer box you choose will make all the difference. Get it right and you’ll be enjoying your sound system for years to come; get it wrong and you may be left thinking you’ve just wasted your money on all the wrong equipment.
Other Helpful Articles for Choosing a Subwoofer Box
- Crutchfield – Choosing a Subwoofer Box
- Sonic Electronix – How to Choose a Subwoofer Box
- Car Audio Fabrication – Check out this site to get custom subwoofer box designs.