Subwoofer Box Types – Sealed, Ported, Vented And Bandpass

So you just bought your dream subwoofer. Congratulations! Now you’re wondering on exactly where to put that monster woofer you bought. You may be wondering about the different options, whether you want a sealed, ported, or a bandpass subwoofer enclosure. You may have done a little bit of your own research but have come to a confusing conclusion with so many different technical terms. Don’t worry; I’ll summarize the effects and the effectiveness of each one for you without all the technical big words.

Sealed Enclosure

These are generally the smallest of the three. If you have a small or a sports car, I recommend this enclosure for your car. There are pros and cons of course. As mentioned, it is advantageously smaller, allowing you to preserve your precious trunk space. They also allow the subwoofers to produce a highly accurate bass, but with the least amount of “boom” out of the three types of enclosures. This is primarily because the box is airtight, leaving no room for air to escape with the sound waves from the interior of the box. Unfortunately, this restriction does require a much more powerful amplifier and subwoofer combination. Unless you have a high-end set that could handle higher wattage, I do not recommend on getting a sealed enclosure setup.

Ported/Vented Enclosure

Because the ported enclosure requires additional room for the vent, it is typically larger than the sealed boxes. If you’re not too concerned about space, this type is a popular solution for most people. The design is based on the vent with which air is allowed to move much more freely, channeling the sound from the interior and the rear of the enclosure to the outside. This gives it a much more boomy effect with less accurate bass response. With vented enclosures, you do not need as much power coming out of your system since the lack of an airtight box allows your subwoofer to move much more freely and the vents allowing you to hear every bit of sound produced by your subwoofer.

Bandpass Enclosure

Bandpass subwoofer boxes are the largest of the three. This is because the design is based on a number of ports and two main chambers-one for your subwoofer and another for air space within the enclosure to resonate. You could probably imagine the sound produced by this behemoth. It produces the least accurate bass but with the greatest level of “boom”. With this enclosure, you can out-boom anyone on the streets of Los Angeles. But remember that bandpass enclosures require a lot of space, so be prepared to sacrifice a lot of trunk space for your setup. Also be mindful that some subwoofers do not work well in bandpass enclosures, so check your product manual before installing them. Ultimately, bandpass boxes are extremely efficient enclosures and demand much less power than the sealed enclosure. Be sure to have a tight install on a bandpass enclosure since any loose parts will easily rattle and could easily be heard on a bandpass setup.

Other Details on Subwoofer Boxes

There are also a few other things to keep in mind when you are deciding between different subwoofer boxes. Most subwoofer enclosures now are constructed using MDF, or Medium Density Fiberboard, these are excellent for enclosures so be sure you’re buying MDF construction boxes and not cheap plastic or plywood. Fiberboard (even if it says medium density) is much denser than any other material so it does not rattle and could withstand very high temperatures. Particle boards are much lighter material and do not bond as tightly as fiberboard and would therefore not be suitable for harsh environments.

Cosmetically, there are usually two options for you to get-a carpet exterior or a vinyl/paint finish. Carpet will protect the exterior from getting scratched and usually matches the trunk color pretty well (gray, black, and tan). Paint or vinyl finish tend to show exterior blemishes much easier than carpeting, but cleaning them is also much easier-especially valuable if you are installing a non-trunk subwoofer enclosure install.

How many subwoofers in a box? This depends on obviously how much money and space you have. Don’t buy two when you can buy one that could produce the power of two. This will potentially save you money and space. If you can help it, do not settle for a set of two cheap ones when you can buy one good one. Yes, two will help add more power and sound, but it sacrifices sound quality for volume and boom.

I hope this short summary have helped you in your decision making process. At the end of the day, it is truly up to you to research your subwoofer and find the best solution for your system. Happy hunting!

Building the Best Subwoofer Speaker Box Enclosure For Your Car Or SUV

Box Building

Each type of sub requires it’s own type of box. If a sub is installed in a box larger or smaller than what is supposed to, it will sound distorted/bad and could be destroyed. Boxes can be built in many shapes, but it is important that the box volume is calculated accurately to achieve maximum performance.

Materials

A box MUST be very sturdy. Most common building materials are 5/8″ or thicker particle board or medium density fiberboard. If building a box with Plexiglas, do not use anything less that 1/2 inch thick. A common material used to mold complex shaped boxes is fiberglass, but it is very hard to work with, and require several layers for a smooth finish.

Gluing, Sealing

Glue should be used at all joints to fill any spaces. Any spaces will degrade the performance of your subs, not to mention the annoying noise air makes when being pushed out of a small hole. On applying the glue, let it cure for at least 24 hours before mounting the subs. This is a precautionary measure to protect the rubbers used to make the subs from the high fumes that some manufacturers glue products have.

Holding Joints Together

In connecting box joints, it is best to screw the joints every four inches or so using 2″ – 2-1/2″ screws. Pre-drill about 3/4″ deep, so that screws do not split the wood at the edges, especially when working with particle/dashboard.

Should I have a Box for Each Sub?

It is advised to have a separate chamber for each sub. Even though not necessary, here are two reasons why such a directive should be taken: First, if one of the subs blows, then the volume of the box will be “twice” as big for the one remaining working sub. This could cause problems and even damage the other sub. The second reason is bracing. Building a box with a divider in the middle will make the box more rigid.

Ports

Ports must be built into your box design to channel out the air made by the sub’s vibrations. If a pre-made port is not available, the most common material is PVC. PVC is very rigid, comes in different diameters. Cut the tubing at the desired length. Consider the volume the port takes up when calculating the box volume. Cut a hole in the box. Make sure the hole is as perfect as possible to minimize gaps between the box and the tube. A couple wood braces can be added for screwing the port top the box. Seal the gaps using a proper sealant (Evo Stick or even silicone can be used).

Bracing

Boxes that are more than a foot in width or length or height, should be braced so that the box becomes more sturdy. This can be accomplished with a piece of wood maybe 3 or 4 inches wide across the box). It is a good idea to put wood blocks on the corners for reinforcement. Always consider that blocks, braces, neon lights, etc. inside a box take up space and should be accounted for when calculating internal volume.

Damping/Filling

Damping increases subwoofer efficiency by dissipating some energy that affects the sub, particularly the voice coil. It is advisable to put damping material inside a box. Pillow polyfill and fiberglass insulation are common, though polyfill is a lot easier on your skin. Polyfill also “tricks” a sub into thinking it is in a bigger box. Play around with different amounts of polyfill until you get the desired results.

Making it look professional

Make the box surface free from holes and spaces by adding wood fill. If you decide to paint the box, then you should apply primer first. Carpet or Vinyl padding is the best covering to use since they easily cover any outer blemishes on the box and give the box a ‘smooth’ outlook. Be careful when cutting the vinyl or carpet since such cutters tend to be very sharp. Cut a piece of carpet (or vinyl) big enough to cover the whole box. Apply adhesive to both box and carpet (EvoStick works great). Wait about a minute and place the fabric over the wood. For the best fit, stretch the fabric when applying it. The fabric should wrap around and end in a place of the box that will not be seen. Do one side at a time, cutting excess carpet. If possible, add staples preferably heavy duty staples that can penetrate the box, to hold the fabric at the ends. NOTE: Do not cover each panel of the box before mounting it together since it would be impossible to find any ‘leaks’ that may exist in the box design much less fill these leaks.