I used 1 1/8" MDF for the front of the cabinet and 3/4" MDF for the rest of the enclosure. The front has insets for the drivers (so they are flush mounted) and the rear of the driver holes is routed down to minimize early reflections. In addition, the top and bottom are rabbeted ( 1/4" ) so that the sides have additional support. The entire loudspeaker is assembled with just glue (I use Titebond 2) using butt joints and rabbets.

Here's a picture of the glue up process. It uses 16 clamps.

The glue up - click the image for a larger view

Here's a view of the panels (press any image for a larger view).

The inside shelf, the top (or bottom) showing the rabbet and the front.	The side with port holes and the rear with hole for posts. The other side is blank.

Here's a closeup of the front of the enclosure showing the inset (front) and the routed area with screw keepers.

The front panel	The back of the front panel