Hello!
Sorry for the delayed reply! I was away for a few days but am back online now.
Thanks for the post and the interest in the FAL's. The FAL's are what I would call a 'wideband driver'. I would also put most all 'fullrange' speakers in the 'wideband' catagory - many having very little real low end response desite heroic efforts with complex cabinets to coax bass out of them. When I played with Lowther/REPS drivers I gave up on the low end and went with a front horn for the driver and then TAD 1601's on the low end below about 150Hz. Bert's Oris horns are like this and can work quite well. The only truely fullrange speaker I have heard is the soundlabs. They are great but not easy to drive or fit in most rooms so that limits them a bit.
Getting back to the FAL's I have measured response from 40 Hz or so to 10K. They fall off above 10K so most anyone would prefer having the tweeter with them. They do run with no crossover on the FAL driver and just a single cap on the tweeter.
FAL also makes a smaller driver that goes higher and can run without a tweeter - but it does not go as low and for most folks a woofer of some kind would be needed. I had a quick listen to the protypes of these last spring and they sounded good but did lack the low end of the larger twin drive system.
I like your goal and have had a similar thing in mind myself for many years now! It is not easy to pull off though. As mentioned above appart from soundlabs I do not know of any really full range drivers. Please let me know what you find as you look around!
Many Thansk!
John Chapman
www.bentaudio.com