Saw and heard these in the late '70s. Sounded very interesting and nice. If I recall, there were five drivers in each one, and a complex crossover too.
Who remembers the Dahlquist DQ-10's?
My first pair of "high-end" speakers. Power hungry critters but what I would give for an updated pair. I powered these with a Peavey CS-400 and a Maccomack Deluxe Line drive passive preamp!! Those were the days! Young and dumb I suppose?