I have spent a lot of time with my trusonic 80FRs. I lived with them in a simple BR configuration (pure single driver with no crossover) for several months. I compared these with other full range drivers that friends & I had ...mostly the fe206E (fostex).
I also demoed my Stepehens Trusonic 80FR pure full range boxes to many people.

In general, most people were not really impressed by the trusonic 80FRs in
pure single driver mode. While they are smooth and have a nice midrange, they have too many problems: too nasal, not enough high frequency and just about OK lows. All of this interferes with any meaninful enjoyment of music, and detailed recordings with many instruments sound really constrained. In comparison, the fe206E, a cheaper driver, has much better frequency extension in PURE single driver mode. THE FOSTEX SOUNDS MUCH BETTER.

After these first few months, I decided to create a multi driver configuration. I added a tweeter, and also a baffle compensation circuit to boost the lows a bit. The result: a 2 driver setup with a fairly complex passive network. The sound: MUCH better. Smooth, but decent frequency extension (though bass below 50 hz is not happening with these drivers unless you seriously compromise sonic fidelity). However, this is a MULTI driver setup...meaning there IS a perceptible loss in coherence, imaging and all the other single driver thingies we cherish. There is also...GASP...a phase shift around 600 Hz....bang in the lower midrange. However, i can at least listen to these now pretty well...i like these almost as much as my still unmodded klipschorns.

To read a semi-independent review of my 2 way setup, please check out:
http://www.audioroundtable.com/SingleDriverSpeakers/messages/386.html

Wayne is a friend of mine...so he waxed a bit more lyrical on the speakers than is warranted!

So, while there is a small fan following of these drivers on single driver websites, in my opinion, the Trusonic 80FR is NOT a great choice for a PURE single driver setup. It is however a decent driver for a 2 or 3 way setup. I don't think Stephens designed them as single drivers either (unlike Lowthers or Fostexes). They were usually part of a multi way configuration for a reason.

If i was doing a PURE single driver setup...there are many choices. I will post a few below for people getting into this hobby:

1. Buy fostex or lowther drivers and get cabinets built...designs exist all over the place, INCLUDING THE Manufacturer websites. www.quarterwave.com is also a good place to look at (though MArtin does use BSC networks so it may not be PURE single driver).

2. www.decware.com has a pure single driver setup they call Tower that should sound good (i have never heard it but Steve Deckert makes good stuff.. i own a zen amp). I think he sells it for around $1500.

3. Ed Schilling makes the horn shoppe speaker for around $700. This has got to be a good deal! He sent me a measured curve once that shows decent extension down to 50-60 HZ. I have never heard them but you see very few used ones on sale.

4. Moth audio's cicada is a good choice as well (again never heard but seen reviews). I think these are in the sub $1000 range also.

5. Classic audio (in St. Louis Missouri) sells the fe206E driver in a 1.2 cubic foot box, again in the sub $1000 range. They also sell many other drivers in other boxes. I have heard the 206E in the 1.2 cubic foot box. It sounds very good. I am not sure about the myriad of other drivers this website sells, and the other cabinets... in my estimation they may or may not sound good. I would be especially careful about Lowthers in bass reflex boxes. However, i can recommend the 206E in their 1.2 cubic foot box, since that is almost optimally designed, and i have actually heard it!

Hope my views help other people getting started in the hobby. Often times, there is hype about a certain driver that leads to unrealistic expectations. I hope I have managed to present a balanced picture here.

thanx,
-akhilesh