Free-air subwoofers:
Free-Air subwoofers are subwoofers that are mounted in the trunk without a box. They are usually mounted either behind the back seat firing forward, or on the rear shelf, firing up. Not any subwoofer should be used in a free-air configuration. Subwoofers that can be used effectively in free-air mode are usually designed specifically for such use. Free-air subwoofers let you keep your trunk space but they require a great amount of amplifier power and do not sound quite as good as subs mounted in a box.

Sealed Enclosures:
These are speaker boxes that are sealed. Thus, no air can enter or leave the box. These generally give very good bass response and can go very low indeed. Generally require less power than a free-air configuration.

Ported Enclosurers:
These are speaker boxes that have a port in them where air can enter and leave the box. These are generally louder than sealed boxes but some care and effort is needed to tune the box so that it will sound just right. If care is not taken, a ported enclosure will give a boomy sound.

There are other types of enclosure but they are all variations of one of these two. These are described in detail in the rec.audio.news FAQ.

Back to the Choosing Good Subwoofers Page.

Please contact me with any comments or suggestions.