High efficiency speakers

I'll echo the suggestion of Coincident and Silverline. Both have excellent SET-friendly solutions. With your bias against d"Appolito alignment might eliminate Coincident though they sure sound great to me. I heard Daedalus speakers sounding absolutely superb at their room at RMAF and I believe that was with ArtAudio SET amplification. They have a very specific look to them as well using some interesting joinery on the cabinets which I'd imagine wouldn't be everyone's taste, though I thought they looked and sounded great.

My bias against powered bass in high efficiecy speakers is just a thought that since these designs use transistor amps for ther woofers, are they forgoing the supposedly sonic superiority of SET over SS amps (even in the bass quality.)?

I don't know how you would actually like it, but before you jump to conclusions about it you should perhaps try listening to some implementations of what you are describing here (basically you're talking about bi-amping). I do think it takes some skill and knowledge, but have heard it done well, though I cannot say it was with a SET amp in the mix. As far as the sonic 'superiority' of SET over SS - IMO (this is coming from a big SET fan who has used 300B 8 watt SET amps in my main system for around 8 or 9 years now) the allure of SET is all in the midrange purity and that magical holography that no other type of amp does so well (OTL is a nice alternative though and comes pretty damn close). I haven't heard any SET amps that can do tight convincing bass as well as an SS amp - that's not to say one doesn't exist, but I haven't heard it if it does. When it comes to pushing those larger woofers that really move a lot of air fast to create the convincing bass, the lower powered amps just are not up to the task when compared to more powerful alternatives. I'd also highly recommend SET and horns, and would have mentioned vintage Klipsch as well but your tastes seem to run in the more exotic realms. Klipschhorns and SET were made for each other. Horns and SET in general are a great match, but they can also be a matter of taste as the sound is unique. I love it myself, but have also heard front loaded horns that bore me to tears or make me want to go running from the room. I tried Zu Druids for a while and didn't warm up to them at all. The success of your implementation of SET and a particular pair of speakers will also be determined by the kind of music you listen to, how loud you like to listen, and the volume of the room you are listening in. Most of the music I like the best is well suited to SET - it is simple, acoustic and or vocals in small arrangements. If you are into densely arranged orchestral, jazz or rock music IMO there are better choices in amplification than SET, and the idea of 'superiority' goes right out the window in comparison with an excellent SS amp when listening to these materials regularly. In this sense SET is kind of a one-trick-pony. It is certainly not the Swiss army knife of amplification. Don't get me wrong, I love what it does well - in those realms it is king when put together with the right speakers. You are right to carefully research that specific interface as it is more critical than ever when using a SET amplifier.

Good luck!

Hey JohnK - I believe you, and am glad to hear it. Please note, I did not say that SET amps could not play rock, punk or pipe organ music. I've also played and enjoyed all that as well as orchestral and other dense and challenging source material with SET and horns. I did not say it was necessarily a bad combination. I only stated that it was my opinion that the denser source material is better served by SS amps in comparison (IMO, of course - you may feel differently). I have not heard any SET amp / speaker combos that serve that type of material better than SS, but there are many out there and I've only listened to a relatively small amount of what's available between shows, dealers and friends, as well as the few I've had at home. So many amps, so little time! Seems like the SET stuff that I have heard that does better with denser material are parallel SET solutions mostly that put out a bit more power. Bel Canto's SET amps were pretty nice in that respect too. I'm glad to hear that more is possible than my experience leads me to believe. It does not surprise me. I've seen some of the unique speakers you've sold here and they certainly look interesting (with much emphasis on bass cabinets as I recall). Thanks also for the clarification on the physics of drivers! As I understand it, transformers also play a big roll in successful implementation of SET topology. I've been using a pair of Mike Sanders Quicksilver 300B SET amps. They're not on his site, but he had a pair at the recent RMAF and was also playing his KT88 based SET amps there as well. Love'em. They do have what seems to be a better bass response than a few other 300B's I've been able to compare them directly too (Wavelength and Wright Sound). That said I don't think bass is a 300B's strong suit. The horns that I've seemed to like the most take up a whole lot of space and need room to breath. While the smaller solutions don't really excite me much. I've recently had to give up my larger workspace and bring my system home and I've been having a hell of a time missing those horns. My modified LaScalas are just too big for my modestly sized home. I've tried a few different speakers looking for that speed and dynamics of horns. Coincident has come the closest with a very similar clarity as well, without any edginess at all. Damn fine speakers, but ultimately I do think they're in need of a bit more power to really sing in my room (the volume of which is rather large overall, while listening is practically nearfield). They do great with the 300B's otherwise except for the deepest of bass notes. If I were in a smaller room I think they might be perfect. 300b's with horns is nirvana for me with much of the music I prefer, but I don't think it is necessarily everyone else's, and I don't think that I might not enjoy other alternatives (and have certainly done just that).