How to Select a Subwoofer Enclosure

You recently purchased a new subwoofer from an online store but neither the website nor the salesman mentioned it requiring an enclosure?

I know it’s hard to believe for most readers but customers have told me this more then once through the years. Although most brick and mortar stores will stock subwoofer enclosures, many online outlets don’t want to bother with them. In fact, many go so far as to never even mention the need for an enclosure in their subwoofer product descriptions.

Let’s see if we can present a guide to enable you to select a proper enclosure for your specific subwoofer. First and foremost, select your subwoofer before considering a subwoofer box. The fact of the matter is that subwoofer boxes are built to quite narrow specifics. You definitely want to match your enclosure to the manufacturer’s suggestions for the subwoofer. I’d estimate that 90% of my shoppers have already purchased their subwoofer before looking for a proper enclosure.

I should mention that if you purchase one of the very few remaining subs listed as “free-air”, you can actually forget about this entire question. The “free-air” sub can be mounted into a large area such as between the passenger compartment of a car and the trunk. In this case, the trunk serves as a large sealed enclosure when it is tightly closed. There aren’t many subwoofers of this type being made anymore.

For the rest of us, we have to read the manufacturer’s spec sheet that accompanied the subwoofer. Of course that is assuming you purchased a new, boxed sub directly from a retailer. If you purchased a used subwoofer on eBay or from some other source, you can search out the manufacturer’s web site and contact them for the specifics of you sub. It is quite important to do so because if you fail to, you can either find yourself with a lousy sounding system at best or damage your sub at worse.

Take your time and decide what would be a near perfect match for your subwoofer. Many audiophiles will insist on constructing their own subwoofer box but through the years I have heard many expensive custom built boxes that sounded less desirable then factory made boxes and many boxes off the shelf that outperformed those home made ones. This is why matching your sub to its box is very important.

Now check the specifics of your subwoofer. See if it recommends using a sealed, vented/ported or bandpass enclosure. These specific types also come in a range of sizes or volumes. These different boxes are actually meant for different purposes or different sounds. A Sealed Box, which is also known as an acoustic suspension enclosure is great for all kinds of music and has the broadest range of frequency response. Sealed boxes deliver tight, controlled bass with excellent Sound Quality and are best for jazz, classical, country or pop music. These are definitely the most popular boxes in use and also take up the least amount of room in your vehicle. They also are the easiest to match to any specific sub.

Another type of sealed subwoofer box which should be mentioned is the custom vehicle specific enclosure. These are usually molded in fiberglass or special plastic composites and fit in ‘out of the way’ locations such as under seats or on sidewalls in SUV’s. These will tend to be a bit more expensive but most buyers feel the custom appearance and convenience are well worth the cost. Normally these come as small sealed type enclosures.

Ported or vented enclosures are usually larger and tend to have a boomier, richer, more resonant sound which lends itself to hip hop and heavy metal music. These are just a bit more difficult to match only due to the additional requirements of port length and so forth. But if you want a bit more BANG for your buck and space isn’t a concern, this type of box might be exactly what you need. Again, be sure your specific sub can be used in a ported enclosure.

Finally we have Bandpass boxes which are the largest and are known for an aggressive, boomy sound which is good for rap, reggae, and hard rock music. Again, you’ll find most subs can be used in a bandpass box but be sure to check on the subwoofer specifics before making your choice.

Really this isn’t as difficult as it might seem at the beginning. For example if your 12” sub says it is suggested for a sealed box volume of .85 cu ft, simply look for a good quality sealed box listed for a 12” sub with an interior volume of about 1 cu ft and you are right on target. Of course there are more specifics to consider in the ported or bandpass boxes, but the steps are the same. You do not have to match volume figures exactly in most cases but you want to come reasonably close.

Although there are unknown numbers of manufacturers of enclosures, there are some general rules that might help you narrow your search. Don’t necessarily choose the least expensive. Reason on this point: why spend good money on a great subwoofer and then buy a cheap piece of junk for a box. Without the proper box, even the best subwoofer will sound like garbage. Don’t be surprised at the shipping costs of your enclosure. One main thing that contributes to good sound quality is the weight of the box, itself. Many shoppers choose to buy their components online but they shop locally for their sub enclosures. The trade off here is that in most cases you’ll never come close to the variety you can find on line and you’ll generally have to pay a local sales tax. Be sure to take this into consideration when shopping locally. It isn’t unheard of, to have a local shop sell you what is in their stock rather then what is best for your specific subwoofer. Match the specifics for yourself before making a decision.

After retailing car audio online for over a decade, you would be surprised at how many customers have purchased boxes from me after they had purchased a cheap box initially and weren’t satisfied with the results. I always suggest being patient even if you have to wait a couple of weeks after your sub purchase to save some extra money. Take your time and match the box to your subwoofer. You’ll love the results.