I hired a professional woodworker to build two Bill Fitzmaurice Autotuba subs. The output was pretty good, but I was not satisfied with the quality of sound. I also built two Rythmik Audio Servo subs in a sealed box. Cabinet was 2 inches thick with bracing and net internal volume of two cubic feet. Sound quality was about the same as the North Creeks, but output was not adequate even with the gain modified by Rythmik. Rythmik Audio does have good service if you happen to do business with them.