Ported Vs. Sealed Subwoofer Boxes for Bass

by Contributor

In the trunk of the majority of car audio enthusiasts, one or more subwoofers are positioned inside a casing known as a "box.' While a variety of types of boxes exist, they can generally be divided into two types, "ported" or "sealed".


The subwoofers are intended to increase the volume of bass, or low-end frequency, emitted from the stereo. The intent of the box is to maximize the level of bass produced by the subwoofers, both in quantity and quality. A poorly constructed or designed casing can often seriously reduce the performance of even an otherwise high-end system. Size is also a consideration, as there is limited space in the trunk of a car for an enclosure to fit.

Sealed Enclosures

A sealed subwoofer enclosure is just that, sealed from any outside air. Once the subwoofer is installed inside this enclosure, there is no way for air to escape or enter it. The advantages offered by such a system include affordability, size and an ability to handle high levels at low frequency. Also, sealed systems are easier to build at home, significantly lowering their cost.

Ported Enclosures

Ported subwoofer systems are similar to sealed systems, except they have a tunnel or vent that allows air to flow in and out of the enclosure. Ported systems are preferred for their superior sound quality and ability to avoid distortion. However, they are generally larger than sealed systems, and much more difficult for someone to build at home.


While fans of either ported or sealed systems are quick to cite their choice as superior, the prevalence of both types in the marketplace is evidence of each of them having its own individual strength. In deciding which route to take, the size of the car, strength of amplifiers and other components, along with budget, must all be taken into account. There are some applications for which a ported system are appropriate, and there are some that necessitate a sealed enclosure.

Common Mistakes

Many people focus too much on the subwoofer and its casing when setting up their car audio system, and ignore other important areas. While it is certainly an important factor in producing high-quality audio, the subwoofer enclosure is not the only thing that should be considered. Position within the trunk, along with what kind of objects or insulation surround the box, can also have immense effects on both the volume and quality of the bass produced by a subwoofer system. Finally, the amplifier, the device that provides power to the subwoofer, should be checked and set up correctly in order to maximize the output of the system as a whole.

Photo Credits

  • photo_camera Image by Flickr.com, courtesy of Chris Metcalf