Today I finished yet another speaker project. This one I designed myself and customized for a client. This project is a large, tall, sealed, 33 ft, 12″ sub woofer enclosure with more than adequate bracing. This is the most heavily braced enclosure I’ve made to date featuring an inverse arc, U shaped rear panel brace and two side panel H shaped braces to provide the stiffest possible enclosure without going to thicker materials. As I gain more experience I’m learning how to design enclosures with smaller effective panel segments and braces that break up the panel to raise resonance. All three braces are glued and screwed down the center as well at at the outer attachments. The brace below is designed with an “inverse arc” along the rear panel. This shape provides the thickest part of the brace centered on the largest, weakest part of the back panel. The holes are cut in the arc to reduce its overall volume impact on the enclosure. Center and front braces are customized to fit the TC LMS 12″ driver magnet as well as provide full length top to bottom bracing in two places along the sides, front to back. The internal bracing reduces panel resonance equal to a 6″ wide panel assuring its resonant characteristics will occur well above its operating range.
The enclosure also features a double thickness baffle plus a magnetically attached, roundover edged grille frame. The double thickness baffle is indexed together to assure an accurate fit and provide a full recess mount for the driver used. The inner baffle is cut to driver mounting specs such that the driver mounts outside it. The outer panel is cut to the external diameter of the driver providing a recessed driver mount in the baffle. Once glued, screwed and clamped to dry the baffle will function as a single piece of MDF a full 1 1/2″ thick not only adding stiffness for the driver mount but also for the entire enclosure.
All braces are dado set (1/8″) into their respective panels as well as on both ends of the brace to ensure a correct location, to provide a more than adequate gluing surface and create a very stiff, strong joint.
Lastly the front, back, top and bottom are all rabbet joined together to provide the strongest possible enclosure seams.