(I'm the guy who asked Bob to create the FTA-2000, but didn't want to preach on my own stuff.)

I've been a MLTL fan since the 70's and more recently a convert to single driver designs. The mighty Fostex F200A makes it possible. Reportedly other driver exist that might match it, but at much higher prices.

At the risk of sidetracking here, I don't believe in doppler effect in extended range drivers. The complex waveform is not made up of separate bass, midrange, and treble signals, but one integrated one, therefore different frequencies are not piggybacked on each other as some would propose. In fact if that were the case, we'd need an infinite number of drivers so that each could reproduce their own unique frequency.

I do agree with Bob regarding the limitations of extended range drivers, but prefer the volume levels and simplier musical forms they do best so it's of little matter to me.

The only example of FE series Fostex drivers that I liked was a FE206E in 0.75 cu. ft. bass reflex cabinet. Wouldn't meet my "full bass" definition, but didn't sound thin like so many others have and mated well with a sub.