Tekton Double Impacts

I also wanted to add that in any build I undertake, I like to maintain a "form flows function" approach (and also follow the KISS rule), by keeping all power circuitry towards the rear of the amp near the AC inlet, and all signal paths towards the front and/or out to the sides. Then find the average operational points of the tubes, and design around that. Use transformers rated for at least 33% more than the duty cycles of the circuits.Then the use of high quality parts come into play (the sum of the parts gives a synergy- much like the blend of a good recipe), keep wiring paths short (twisting filament wiring to cancel AC fields, shielding signal wiring wherever it may encroach a power circuit, etc.). Lastly isolate the chassis from audio and signal grounds and use a star/single point termination for the ground reference. I’ve found that maintaining all of these aspects in any build yields a reliable and typically a great sounding piece of gear.

Thanks Aric. Good stuff.

+1 Sbayne. Tom is going to receive an excellent custom built amplifier from Aric.
Charles 

Very interesting speakers!  The stereophile mention of the Impact monitors had me searching around and I landed on this thread for the DIs as well a very favorable convincing video review of the DIs by Zerofidelity.  
The idea of the ring of tweeters as the "midrange" driver surrounding the tweeter in point source fashion is nothing short of genius. 
The properties of the SB acoustics tweeter made it possible- low mass voice coil for high efficiency, very low Fs for a tweeter that allows a relatively low high pass crossover frequency as well as linear response and very low distortion.  Kudos to Tekton for a brilliant application!  
Seems to open the door for more possibilities too.  The woofer to midrange crossover is likely around 1300 Hz or so (rule of thumb is to double the Fs of 680 Hz).  1300Hz is smack in the middle of the midrange and highly directional and a true point source driver would deliver more of the mid band, e.g. the KEF LS50 delivers down to woofer frequencies while the R-series midrange coincident arrangement delivers down to 300 Hz or so.  In other words the handoff between the midrange ring and the midwoofers needs to be well engineered for phase and coherency. 
You then start wondering what if the ring of tweeters were replaced by a ring of smaller midrange drivers, e.g. the 3" Tympany drivers that can play down to 300Hz or so,   If you can do that, then these speakers would be a tremendous candidate for bi-amping with a tube amp driving the midrange and up as a possibility.   
Another concern is level matching.  The ring of tweeters acting as midrange have approximately 14 db more output than the tweeter they are handing off to (because of the number of drivers).  The mid-ring needs some extensive resistor padding in order to match the level of the tweeter and because the difference is so great, resistor quality and value tolerance over time may become a concern because they are likely going to get very warm if not hot and capable of handling at least 320 watts at max rated power. 

For those of you that own these speakers, how is the quality of the sound in terms of cleanliness?  Freedom from distortion, dirt, noise, grit, ringing, harshness, etc? 

Revolutionary speakers and could be world beaters if they are engineered right.  Can't wait to hear them!   
 

@avanti1960 

For those of you that own these speakers, how is the quality of the sound in terms of cleanliness? Freedom from distortion, dirt, noise, grit, ringing, harshness, etc?

Clean. Free (though not in a perfect absolute sense) of the issues you ask about in the second question.