Audioholics provided me with the link to a review of MBL's 101 X-treme Reference speaker system that costs $263K. If they sound half as good as they look they would be fantastic. Then a vague memory began nagging me. I remember there was an exotic speaker with a fantastic claim: a single driver could reproduce the entire audio spectrum of 20Hz - 20,000Hz. As I recall, this driver was called a "wave transmission line transducer" and looked like an upside down funnel. It was invented by Lincoln Walsh and the company that manufactured it was Ohm. It seems that Ohm Speakers are still around. I never heard them but I'd like for you to chip in and give me your verdict, including an explanation for its mechanism. Thank you.
Google Images.