Image Dynamics USA ID V4 Series Owner's Manual page 7

BOX CONSTRUCTION
The material used for enclosure walls should be solid, dense and free of voids or warps.
Your enclosure should be made ¾" or 19mm material, Finland or Baltic birch type
plywood is recommended where the enclosure will be transported frequently.
High-density fiberboard - MDF (not chip board) can be used on permanently installed
systems. Minimum of 1" (25mm) or double ¾" (1-1/2") baffle is recommended on high-
powered SPL applications.
Corners must be strong and air tight and should not have any air leaks or openings.
Joints should be properly filled with glue that will not crack under high stress or impact.
If the integrity of the glue seal can't be determined, hot glue or RTV caulking should be
used to seal all seams.
Fiber reinforced resin may also be used to form any difficult shapes. However avoid
making large panels with resin to eliminate any chances of box flexing, cracking or
ratting under high pressure.
Bracing made of 2 x 2" or 2 x 4" should be liberally applied either inside or outside the
cabinet, depending on whether the cabinet is to be permanently installed or portable.
This principle applies to any walls of the enclosure spanning more than 18" long. Any
braces should also be liberally glued or screwed down on edge. Edge-wise drilled, and
countersunk holes through the braces can be used for #10-2 Flathead wood screws to
avoid the use of more expensive lag bolts.
The majority of strength from an enclosure comes from the glue. When using screws be
sure to pre-drill holes to avoid splitting the wood.
WARNING! The use of silicone rubber to seal in a speaker will void the Warranty! If any
sealing is needed in addition to the speaker's gasket, use caulking cord or vinyl weather
strip.
SUBWOOFER CROSSOVER SETTING
Your Image Dynamics subwoofers will perform best if they are used in conjuction with
a subwoofer crossover of some kind. Using a crossover will remove unwanted high
frequencies and allow them to concentrate only on bass.
The two most common types of crossovers are "passive" or "active" (electronic
crossovers are active). Many amplifiers have a built in Low Pass (LPF) electronic
crossover circuit. For optimum subwoofer performance we recommend an initial
electronic crossover setting between 50-100Hz and then tuning the bass to your liking.
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