For anyone around DFW the first week of May, the designer of these speakers will be at the Lone Star Audio Fest in Dallas. Looks like a good show this year with numerous displays, many of which have not been in attendance at prior shows. Bob Brines will be there and his speakers are always the highlight of the show IMO.
go look up the Pass creation called 'Kleinhorn'. Massive.
And the sub he built to go with it. A gigantic 'tube' with a box on the bottom with, in its first incarnation, multiple 18" woofers. Flat to 16hz or some such.