Thought I'd share a couple of construction pics of the sub I'm building for our church.
For size reference, notice my full-sized BD drill and a CD. The cabinet doesn't have to be pretty - it will be covered with carpet, complete with road handles, protective corners, a castored base, etc. It DOES have to be a tank - I'm not done with the internal bracing yet.
Peavey 18" Lowrider; 9ft3 acoustic volume, 5.5"x10"x12.5" port; 1000w amp.
First pic is front of baffle; second pic is driver (with a CD); third pic is rear of baffle - you can see the second-layer "inset" panel screwed to the outer baffle, which has the nest for the port. This will get a layer of plywood over it for the driver screws to bite.