All three ACI subwoofers work very well for custom, in-cabinet applications.
We suggest ordering the Satin Black version of the Force XL, Titan XL or Maestro XL to reduce cost. There are essentially two options for placement
Generally, you will want to place them in the cabinet at or near floor level. Place them in a space that is large enough that they will not be touching the inside of the cabinet. For the Force XL and Titan XL you will want the amplifier facing forward for easy hookup and access to the controls. If possible, have the subwoofer sitting directly on the floor rather than sitting on a cabinet shelf, (you want to avoid vibrating the cabinet from direct contact). If the sub(s) must be placed on a cabinet shelf, that shelf should be as heavy and braced as possible. You might also want to consider using an isolation device such as the Auralex Subdude, (do a Google search).
To convert one of our subs to front firing you may remove the base plate by removing the four screws that attach it. Then, you will simply be laying the sub on it's side or front. If possible, have the subwoofer sitting directly on the floor rather than sitting on a cabinet shelf, (you want to avoid vibrating the cabinet from direct contact). If the sub(s) must be placed on a cabinet shelf, that shelf should be as heavy and braced as possible. You might also want to consider using an isolation device such as the Auralex Subdude, (do a Google search).For the Force XL or Titan XL you will want the amplifier to be on the top of the cabinet for most efficient cooling. There should be at least 4" above the amplifier for proper air flow.
Grills may be made from any synthetic cloth that will pass light. Ideally, you want to be able to fold the cloth twice and still be able to see light through it. The cloth should be tightly stretched on it's frame and held in place by staples or suitable adhesive. The shape of the grill is not important but you will want to use the following minimum size guidelines, larger grills are fine:
Force XL: 40 sq.in.
Titan XL: 60 sq.in.
Maestro XL: 180 sq.in.