Polk Audio EX Series II Subwoofer EX652a - Manual (Page 6)

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DESIGNING YOUR POLK EX SUBWOOFER ENCLOSURE STEP BY STEP
1.) How much room do you have to work with in your car or truck?
2.) Which of the above enclosures sounds the best to you?
When designing your subwoofer enclosure, the first thing you need to figure out is just how
large an enclosure will fit in your vehicle. When an enclosure is going in the trunk of a car,
you first need to measure your trunk to find the maximum height, width, and depth
available. Pay attention to trunk hinges and tension bars. If your enclosure is going in an
area other than a trunk, make sure you check for similar obstructions. After measuring,
subtract 1.5" from each dimension. This compensates for the thickness of the material you
use, and will give you your usable (internal) dimensions. Record these dimensions in the
space below for future reference.
Maximum dimensions Usable dimensions
Height:__________inches (Minus 1.5 inches)=______inches
Width:___________inches (Minus 1.5 inches)=______inches
Depth:___________inches (Minus 1.5 inches)=______inches
Usable volume=________cubic inches
Usable volume=________cubic feet
Multiply your usable Width x Height x Depth. The product will be the usable (internal) volume
of your enclosure in cubic inches. Divide this number by 1728 (the number of cubic inches in a
cubic foot). This will give you the internal volume in cubic feet. Divide your internal cubic feet
by 2 (only if you are using a pair of EX subwoofers). Compare this number to the chart on page
14 of this manual. Choose the recommended enclosure which is closest in size. Now that you
have all of your needed dimensions, you can begin cutting your wood. From the above chart
you can tell how big each piece of wood should be. Here’s a sample enclosure.
Maximum dimensions Usable dimensions
Height:__________inches (Minus 1.5 inches)=______inches
Width:___________inches (Minus 1.5 inches)=______inches
Depth:___________inches (Minus 1.5 inches)=______inches
Usable volume=________cubic inches
Usable volume=________cubic feet
By looking on the chart at the bottom of page 14 of this manual, you’ll find that this usable
volume is slightly more than double the recommended volume for a single EX12, in either
a sealed or vented enclosure. Assuming that you will be using a pair this will work out well.
If you are using a single subwoofer, you can cut your width in half. Since we will be using a
pair of EX12 subwoofers for our sample enclosure, we now need to determine the center
divider displacement and the resulting total usable volume. This can be figured out by
multiplying the height x depth x thickness of the divider, and subtracting that number from
the total usable cubic inches. Using the example above yields the following result:
[5440 in
3 - (16" x 10" x 3/4")] = [5440 in 3 - 120 in 3 ] = 5320 in 3 total usable volume.
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You now have all the dimensions you need to begin cutting out your wood. The illustration
above shows a diagram of the enclosure with all the panel sizes that need to be cut.
After you have cut all of the wood, it’s time to start assembling your enclosure. Before you
assemble your enclosure there are a few things we recommend doing. You will need to cut
out the hole for your EX subwoofer and your terminal cup. The terminal cup is a connector
that allows you to plug and unplug the wires from your amplifier into the enclosure. You
may want to have a friend help you with assembly since it’s hard to hold the pieces together
and assemble them at the same time. When building your subwoofer enclosure, we suggest
that you use wood glue in combination with wood screws for the strongest joint. We also
suggest that you use one screw about every three inches along the seams of your enclosure.
Assemble the enclosure as shown in the above diagram, but leave one side off. We suggest
that you leave off the baffle board. This will allow you to seal your enclosure more easily,
and an air-tight seal is crucial! The best way to insure an air-tight seal is to seal the inside of
your enclosure with quality silicone caulk. This also includes sealing around your input
terminal cup, and, if you are using a ported enclosure, around your port. It is not advised to
use silicone around your subwoofer when mounting it to the baffle. Instead, we recommend
using the foam gasket weather stripping supplied with your EX subwoofer. When mounting
your subwoofer to the baffle board, pre-drill your mounting holes using the template
supplied. This will make the mounting of your subwoofer easier and will help prevent
damage to your subwoofer from a slip of the drill. When securing your subwoofer to the
enclosure we recommend using bolts and tee-nuts, but if you prefer, you can use wood
screws. Whichever you use, make sure it is at least 1.25" long. This will insure a good grip
into the wood.
17 1/2" 16"
34"
35 1/2"
10"
11 1/2"
FIGURE 5.
17.5
35.5
11.5 16
34
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5440
3.15