Plan #3 - Bandpass Subwoofer Enclosure, Single Reflex


bandpass subwoofer outputWinISD recommends a 2.5 cubic foot box with a 42 Hz tuning frequency for our bandpass enclosure. The rear enclosure volume is 1.5 cubic feet and the front enclosure is one cubic foot. Using a four inch port we'll need a vent that is fifteen inches long. We must take this volume into account. The volume of a cylinder is pi*r^2*h, or (3.14)*(2)^2*15 = 188 cubic inches. Divide this by 1,728 to get cubic feet and we add 0.11 cubic feet to the front enclosure. We'll achieve this by using 3/4 " MDF for the enclosure with external dimensions of 18.5" x 28.5 " x 11.5 ". This will be a simple rectangular box. Modeling the enclosure we see that it has a 87 dB sensitivity and a -3dB (half power) frequency at 27 Hz and 70 Hz. This box should give incredible amounts of output when used with rap or other music with a lot of 50-60Hz energy.


Here is the layout of our subwoofer enclosure. We will need to cut the following pieces:


28.5" x 11.5"
28.5" x 17"
17" x 10"


bandpass enclosure plans


build subwoofer box

You should also check out Advanced Enclosure Design and Fabrication. It covers designing enclosures using free computer software, maximizing the output of a subwoofer system, building the box like a pro and testing the output using inexpensive equipment. Click here.


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