There are a whole butt load of different kind of boxes. But mainly in car audio we use sealed, ported, or bandpass.
Sealed is the smallest, easiest to build, and has the best low end extension. But this all comes with a reduction in the output.
Ported is larger than sealed, little harder to build, depending on the tuning of the ports can have good low end, but not as good as sealed. But a ported box has great output.
Bandpass boxes are usually pretty large, a whole lot harder to build correctly than the other types. but the have the greatest output around the tuned frequency. This also comes at a price of reduction in sound quality.
Each kind has it's strong points as well as it's weak points. There is no such thing as the perfect box. It all depends on the limitations of your space, the subs themselves, and your personal taste. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif