Why not horns?

Its an interesting horn design, but of course it is essentially only one driver to be built into a full range speaker system. Like most things, the results would depend on how well the whole end package is executed and the only way to know if it were truly an upgrade in the end would be to try a system that uses it and compare. Assuming 98db efficiency and a flat response along the lines indicated by the chart showing measured response of the custom built design in the reference provided, those are a good set of initial indicators, but of course do not assure anything.

I'm assuming the multi-driver design of this horn helps achieve higher efficiency? Other than that, I am not sure what the advantage of horn loading 4 midrange drivers rather than one would be? I am not a fan in general of systems that use multiple drivers to cover the same part of the frequency spectrum because I believe it is harder to do that well and costs are driven up.

An interesting and somewhat different design nonetheless and one that has apparently been built into some affordable end user systems, so that is good.

Danley is very innovative and according to the few people I've talked to who know his work is in a class by himself. His speakers are said to sound very good and his tapped horns and Unity drive are changing things quickly. The main reasons to hesitate buying his speakers have to do with size/scale and cosmetics. They are not compact and they are not offered in wood veneer. They are well engineered, innovative and inexpensive however.

2 X 15" woofers and +/- 3 db 45 Hz, I'm not impressed. The 4 Ohm load might not be too appealing to many horn enthusiasts either.

" The 4 Ohm load might not be too appealing to many horn enthusiasts either."

That would probably work against using most tube amps home audio enthusiasts often look to for use with high efficiency speakers.

Could see it fit easily for pro use where SS is the norm.

Also I suppose the 4 driver approach would enable higher volumes with less distortion/breakup, which would be beneficial to pro applications in particular where good sound at high volume is needed in larger rooms using not many watts. Those watts would probably be SS state though.

Gotta keep in mind that pro audio requirements are different than home audio. I'm sure the speakers would sound at least OK in smaller quarters aat most volumes one would attempt, but the strength of the design would seem to be more in the pro applications as described.