That first one, beside the esthetics, Looks much larger than the cubic measures that were discussed. That looks more like 4.5 X10 X 7 with a front facing port. Since it will be on a stand-like structure, it could have a down firing port? I am wondering what the material you used for the 3D printer? You must have used a ton of it to make the walls thick?
Thanks for sharing them. I kind of enjoy the work-in-progress shots.
The 4" x6.25" x 7.5" is the internal volume. So add an extra inch in each direction and you've got the external size. The walls are 1/2 inch thick.
The updated version will be 4.5" x5.75" x7.5" internally, and the port will need to be about 4" deep instead of the 2" in the current version.
I use PLA. Until this project I normally use 1KG spools. But im currently using a 3KG spool from Polymaker.
A down-firing port was the initial plan, but the front-mounted port allows for a small bump in overall effeciency
We may make both versions to see which one performs better.
I used 50% infill on the base and lower half, the upper half and top are 40% infill there's probably 1.6kg of filament in this version.
There's a bit of ringing going on at one frequency but I think it's likely just the cabinet resonances/reflections that dont exist in the original test cabinet.
That jet engine design looks rad! Completely over the top and impractical for most people to build, but a painted up set of those would be a super cool one of a kind speaker. 
You guys should keep pushing the envelope. I triple-dog dare you.
Maybe sometime in the near future I can work on it a little more and use bondo to smooth it over some more.
But it's not in the cards at the moment.
