Even the easiest do-it-yourself subwoofer can turn into an arduous project; from uneven cuts, to measuring mistakes. CNC knock-down cabinets make it easy for the beginner to end up with amazing finished results without all of the time and effort necessary to perfect your woodworking skills. This cabinet is designed for speaker builders and designers who don't have access to expensive tools or a woodshop. This particular cabinet is designed specifically for the Dayton Audio UM18-22 18" Ultimax subwoofer, but works for any subwoofer with an overall diameter of 18-3/8" or less, and a cutout requirement of 16-3/4" or less. The sealed enclosure design with minimal fill creates a subwoofer system with a Qtc of 0.73 and an f3 of 33 Hz when used with the Dayton Audio UM18-22. Adding five pounds of Acousta-Stuf will create a critically damped subwoofer system. During the CNC manufacturing process, rabbets dadoes are cut into the back panel for precise panel alignment. A unique two-piece brace adds superior rigidity without affecting the subwoofer's performance. Both side panels feature 3/4" rabbeted extensions with recesses to perfectly install the first piece of the two-part, double thick baffle. Plate amplifier installation is made easy by following the scribed interior guide with a jig saw and by modifying one of the braces. The end result is a resonance-free, sealed subwoofer cabinet that is purpose-built to extract the best performance from Dayton Audio's 18" Ultimax subwoofer. All that's left to do is finish it to match your décor or paint it to stand out. When your friends ask about it, you get the pleasure of saying, "I built it myself!"