The type of bass you get from your component subwoofer doesn't depend on the woofer alone. You'll need a strong, tightly-constructed enclosure, such the Q-Logic boxes offered by Crutchfield, for optimum subwoofer performance. Speakers without an enclosure can't deliver full bass because the sound from the back of the speaker can cancel out some low frequencies emanating from the front of the speaker.

Using our box-building accessories, you might choose to construct your own box to create the enclosure size that you want. However, unless you have excellent craftsman skills and a solid understanding of enclosure volumes and other technical terms, you're better off purchasing a convenient, professional-looking pre-made enclosure.

Different types of boxes will produce different types of bass:

Sealed boxes: For deep, precise bass
A sealed box is an airtight enclosure housing your subwoofer. A sealed box is best for any music that demands tight, accurate bass. Expect flat response (not excessively boomy), deep bass extension, and excellent power handling. Since a sealed enclosure tends to require more power than a ported box, use an amplifier with ample wattage for optimum performance.

Ported boxes: For forceful bass
Ported boxes use a vent (called a port) to reinforce low bass response. You get more output than you would from a sealed box at any given amplifier wattage. Some people prefer the sound of ported boxes for rock, heavy metal, or any hard-driving music. Ported boxes can deliver deeper bass than sealed boxes, though they need to be much larger than sealed enclosures to accomplish that.

Bandpass boxes: Maximum slam
Bandpass boxes are a special type of ported box designed for maximum slam. The woofer is mounted inside a dual-chambered box (one chamber sealed, the other ported), with the sound waves emerging from the ported side. The sound that comes out of the port is extra loud within a narrow frequency range.

Because bandpass boxes are super efficient within that range, they tend to boom. Their aggressive sound is great for rap, reggae, and hard rock. Not all subwoofers work well in bandpass boxes, though; consult our product information or call one of our Advisors to be sure.

Choosing an enclosure for your subwoofer
Q-Logic's convenient enclosure ratings are being adopted by more and more manufacturers. Here's how it works — pick a subwoofer from Crutchfield's wide selection, and you'll notice a recommendation for "Box Type" listed in the sub's Key Features (based on the manufacturer's air space recommendations). We check every sub for fit, so if you want to see boxes that work with the sub you selected, click on "Recommended Accessories." If you don't see a particular box listed for your sub (or if no box is listed), call an Advisor at 1-888-955-6000 to check out your options.

Q-Logic Box Types

• Type 1: Small, sealed box — produces tight, focused bass. The most accurate bass response of all box types, but requires more power.
• Type 2: Medium box — comes equipped with pre-cut port hole(s), port hole plug(s), and ports, so it can be used for either sealed or ported applications. More efficient than a sealed box, so you get more bass SPL with a little less accuracy.
• Type 3: Large Box — comes equipped with pre-cut port hole(s), port hole plug(s), and ports, so it can be used for either sealed or ported applications. Much more efficient than a sealed box, so you get more boom for your buck, but with less accuracy.
• Type 4: Bandpass Box — sealed/ported hybrid. Highly efficient, but with less accuracy.

Free-air subwoofers
A free-air system consists of woofers mounted to a board attached to the rear deck or placed in the trunk against the rear seat. The trunk of the car acts as an enclosure which houses the subwoofer and isolates sound from the back of the speaker, solving the sound cancellation problem of subs without an enclosure.

Free-air systems save space and have flat frequency response. The woofer must be specifically designed for free-air use. The lack of a box makes them more convenient to install, but their power handling levels are usually much lower than their boxed counterparts.