Anyone Familar With ESS Speakers?

The other posts have pretty much said it all, but I'll throw in one more point. I sold audio gear on a part-time basis in 1974-75, and the store where I worked carried the ESS Heil speakers (that name always makes me want to put on German martial music, goose-step around the room, and yell "Sieg Heil" ...). The speaker design was interesting, but they were/are terribly inefficient. The pair in the store was driven by the old Phase Linear amp, one of Bob Carver's earliest designs (also known as "Flame Linear" for reasons that should be self-explanatory). Even with 300 wpc driving them, the Heils still sounded pretty awful, and I can't imagine they'll sound any better today.