I've almost completed the Passive Speaker project. The parts are done (above) and I've completed the photography.
I got thrown off a bit with the iPhone version and ended up designing the centre section upside down so the horn pointed straight to the ground. Oops! These things happen. Luckily the design is on a computer so it was easy to modify the file as needed and print it out again.
I think you'll agree that it is a thing of beauty! Should be on the site tomorrow (And probably on Instructables as well)