This is a build log for a custom set of speakers I built for a friend.
I made a subwoofer similar to the "Voxel" design from Paul Carmody. I made it slightly larger, increased the port diameter, tuned slightly lower, and added a Lepai plate amplifier. I am *very* impressed with the output for the size. That said, this particular subwoofer is a little underpowered to be paired with the TriTrix speaker design if it is required to supply all of the bass. Instead of crossing over the speakers to the subwoofer, I am using the subwoofer for a bit of extension and to fill out the room modes.
In the final arrangement, I put a 30Hz HPF on both the speakers and subwoofer, and a 120Hz LPF on the subwoofer with a smooth rolloff. I also turned down the subwoofer relative to the speakers a bit. I use a similar arrangement on my system at home and I really like how it creates smooth and consistent bass throughout the listening environment. It tends to work best if the subwoofer is relatively close to the speakers.
In the end, I applied 24 coats of paint over 6 paint sessions. Each "session" I applied four light coats of paint 8 minutes apart. Then waited 24 hours and started the filling/sanding process and doing it again. The finish turned out great and is very durable.