Sunnyjim,interesting stuff.I have some Crown ES212s which use similar RTR made stat panels.The Crowns use 12 5inch stat panels arranged in a curved screen 3 high by 4 wide.The bass [below 350hz] is handled by two ten inch woofers in a sealed box.Even by todays standards they sound superb.They are clearly better than the older Quads and many of the Martin Logans I have heard.They are surprisingly dynamic and have real world loudness capabilities.Apparently they cost the same as a family sedan in the mid 70s so they should be good.
JT
JT