Last Winter my son and I built a pair of Fusion 8 Alchemy speakers for him and I posted it in this AC thread:
http://www.audiocircle.com/index.php?topic=139584.0The speakers came out great and best of all they survived his first year in college.
When my son came home for the Summer he asked if we could add a subwoofer. This seemed a reasonable request given that the Fusion 8 speakers were designed to be paired with a subwoofer. They have a 55-60 Hz low end extension.
Originally, I was very impressed with the DIY Sound Group's flat pack for the speaker cabinets, so I decided to go with the Parts Express 1 cu ft flat pack (supplied by DIY Sound Group) combined with the Dayton 10" Reference HO driver. The 3/4 inch MDF panels were even easier to assemble and more precisely cut than the BB plywood panels of the Fusion 8.
Here are some images:



After sanding the cabinets we decided for consistency to use Duratex paint. I have to say the second time is a lot easier.

The cut out on the back is for the Yung SD300 class D plate amplifier. The back panel came already precisely marked but we had to cut it ourselves.

Remembering that Duratex needs time to cure we waited 4 days before the final assembly. Again, it was very easy.



The final touch was a metal bar grille that my son decided to attach diagonally. It does look very interesting this way.
So, how does it sound. With no break-in and no care about placement, I have to say that music is rounder, fuller, more life like and has that great, visceral component.
If you care about DIY - highly recommended!