Thiel Owners

I think the old Walsh and new DDD mostly bending wave drivers (there seems to some combined pistonic motion too) might prove that pistonic motion is not a requirement for time and phase accuracy. The Quad ESL ‘63 is another work around that would appear to dispel the notion of a pistonic motion requirement for time and phase accuracy, Of the above mentioned examples, It should be noted that none use 1st order cross-overs either. Though to be fair I think only the limited production Walsh A could be considered full range, and that model seemed to be plagued with reliability concerns. HHR Exotics claims their updated version of the Walsh drivers have addressed many of the concerns of the original Walsh drivers.

The ESL-63 uses (if I recall correctly) a cascading time delay crossover over concentric rings of the diaphragm to create a whole diaphragm motion with all points equidistant from the listener's ear. What brilliance!
"Walsh" - type drivers use bending in their method of creating the cylindrical column of moving air pressure waves. So bending is part of their basic system mechanics.

Discrete drivers attempt a uniform air propagation wave-front  via multiple driving sources, which must remain flat to engage the air mass properly.
Unsound - do you know if the Walsh-type driver actually produces intact step response at the listener's position?

So a question, where would Kef's Uni-Q concentric driver array fit into this mix?

There's some explanations of the Walsh driver characteristics at Ohm's website - https://ohmspeaker.com/technology/

Unsound maybe you found this.
With much info contained.
I would be interested in seeing how the driver is terminated on the edges so some polarity of the signal does not return into the path of the next uncoming signal.
Same thoughts on any of the Walsh drivers the inside and outside of the cone must react with some signal inversion. Tom.   https://www.bendingwaveusa.com/technology/