Building a speaker box is the most basic of all installation processes. There's no magic to it, only the knowledge of the product that you're working with. Yet every day, someone, somewhere is dishing out big bucks to get that big beat in their trunk. To help you save for that big paint job or new set of rims, we're going to help you break the secret code and make building that big bass box as easy as changing your oil.

There are a few things that we look at when building a box, but most important are the areas that we have to work with and the air space requirements for the subwoofers that we would like to use. The first and foremost decision that has to be made is what you can fit in the area allowed. Beyond that, following the guidelines below should make box building easy.

Calculating Air SpaceWhen a manufacturer provides you with a box dimension they typically use a box building program that takes into account the different parameters of the speaker's characteristics. The result is recommended air space that every manufacturer will happily provide to you. The problem is that most people just don't know how to apply this information. The typical response back to a manufacturer after they have provided the recommended air space is, "So how big is the box supposed to be?" or "Can't you just tell the measurements?" The short answer is no. There are too many variables, like the opening of your trunk, total available height, total available width, etc.

So air space can be figured with a basic algebraic equation: (height x width x depth)/1728, where the measurements are in inches and only account for the inner box dimensions (not including wood width). So in the case of 1 cubic foot box, the basic calculation would be (12 x 12 x 12)/1728. When you plug that into a calculator the final answer is 1.

Additionally, you need to take into consideration the speaker displacement. The latest and greatest subwoofers are big dense monsters compared to the speakers of 10 years ago. So the displacement could go from the average .05 cubic inches to double or even triple, which will throw your total interior air space calculations way off. So read the specification sheet included with your subs carefully and take every aspect into account.

There are, of course, more sophisticated and complicated ways to get the correct information, like computer programs, but these basic guidelines will help you build a decent sound enclosure.