When you mind and heart are not open......then you react from your ego.
These are probably the woofs he is using:
https://usspeaker.com/beyma%2012BR70-1.htm
Here is the wire he is using:
For $1200 you can buy the 4 woofs, 2 tweeters, wire and all xover parts.. This would be usng an even better coil on the midrange (Jantzen 12 gauge waxed paper foil). Then you make a baffle and wire it up. I would not use binding posts. I would hardwire the speaker cable to the wires going to the xover parts.
Another possibility would be to cut off the back of the tweeter so there is no chamber. This would lower the resonant frequency of the tweeter and probably allow a more transparent sound. However, power handling could be compromised. I do this to my Vifa tweeters that are sitting on top of my two way speaker. The Vifa tweeter sounds way better with the back cut off. However, it is not doing real low frequencies like the one in the Caladan. However, if you used a digital xover and used steep slopes then you could cross it over at 1K and play 110db.
Another possibility would be to make the speaker with just the woofs and then put a shelf on top and mount the tweeter on a recessed baffle with felt on the top of the speaker to time align the tweeter with the woofs. Mucho better than just tilting the speaker back a bit. Of course, everything I suggest has to be measured and listened to.
You can just make the baffle with the drivers mounted and use a $500 Minidsp Flex as the digital xover. Then you need two amps (modded Fosi V3 would be great for the bass and inexpensive). This way you can time align the tweeter to the woofs and equalize the whole speaker and use whatever amps you want on the woofs and tweets......but if you are going to go that far then you might as well use a stack of 4 planars for the mids and highs and cross over at 400hz as explained before and on my website.
Only about 5% of audiophiles are DIYers......so this info is not hurting Clayton's pocketbook. Most of you are rolling your eyes after reading all this.....he he. It is good eye exercise.
Have fun!