Determine the Space Available for Your Enclosure

Before deciding on a particular type of enclosure to use, you must first determine the amount of space you have available. This is a very important step to ensure you have the appropriate volume needed to provide proper performance of the subwoofer. For example, if you wish to build an enclosure for a 15" and you only have one cubic foot space available, it would be better to use a 10" because the volume is not large enough to allow the 15" to perform properly. The small enclosure would restrict the performance of the 15" not allowing it properly reproduce low frequencies.

Enclosure Types

Sealed Enclosure:

Advantages:
Easy to build, smaller enclosure size, lean tight sounding bass, better power handling vs. ported design and Linear low bass extension.

Disadvantages:
Less efficient as compared to ported design.

Ported Enclosure (Bass Reflex):

Advantages:
More output at the tuning frequency as compared to the same woofer in a sealed enclosure, higher efficiency.

Disadvantages:
Larger enclosure size, Calculating enclosure and port dimensions more difficult, easy to blow woofer if power handling limit is exceeded.

Bandpass Enclosure (4th Order):

Advantages:
Bandpass can be designed to play loud or low depending on your needs, by design produce a limited band with, the woofer cone does not move as much other designs reducing the chance of added distortion.

Disadvantages:
Bandpass boxes have a tendency to sound boomy not tight, typically these enclosures don't sound as good reproducing Music requiring great detail such as Jazz or Classical music.

Enclosure Materials

It is recommended to build your enclosure from 3/4” thick MDF (medium density fiberboard). Make sure the enclosure is sealed air tight.

To calculate box volume, measure the outside Width x Height x Depth of the enclosure. Example 12” x 14” x 9” = 1512”.

Next you must convert cubic inches into cubic feet. To do this, you must divide the cubic inch total by 1728”. Example 1512 1728 = .875 Cubic feet

To calculate the internal (net) volume of the above box you must first multiply the thickness of the wood you are using by Two (2). Example: 3/4” x 2 = 1.5”.

Next subtract 1.5 from each of the outside measurements of the box.

Width	Height	Depth
12-1.5 = 10.5	14-1.5 = 12.5	9-1.5 = 7.5

Multiply the new totals (H x W x D) Example: 10.5 x 12.5 x 7.5 = 984.375

Next you must convert cubic inches into cubic feet. To do this, you must divide the cubic inch total by 1728” Example 984.375 1728 = .5696 Cubic feet.