High Sensitvity = good transient response ?

Marakanetz, I do indeed enjoy your posts and feel you are a very informed and perceptive individual. On the high-efficiency speaker with SET comment you made, though, I believe you are in error. If you sat down in front of my system which consists of a 1 watt triode OTL, and a pair of Lowther 100db/1 watt fullrange, you would wonder how anyone could say that "voice is the only thing you can listen to". Granted, the bass is somewhat limited to around 40 cycles and there is some "vented" sound to the lowest bass. But,it is very, very good from there on up to 22kHz. As I said in my last post, many other high-end speakers also roll off around 40, and have vented bass, so this is not unusual. Many extreme audiophiles consider this type of system to be the most musical and natural of all systems. They are not idiots. There is definitely something to be said for this type of system. I am hoping that you were exaggerating your point somewhat, because wide-frequency extension is not limited with these systems with the exception of the lowest octave. Some lesser-quality transformer-based SET's may roll off the highs due to transformer induced problems, but not on my system. In any case, the addition of a sub would cover all freq's well, and this is quite common with many types of other high-end systems as is well-evidenced by the plethora of subwoofer threads on this forum. I felt the need to take issue with that statement, because I thought that it was too stereotypical, and an overstatement. Our members who do not know about SET/high-efficiency systems deserve a fair assessment for their knowledge base. I take no personal issue with you, but only wish to set the record straight.

Thanks for honoring my posts, TWL as I honor yours the same. I have many reasons to believe you and probably I should give myself another chance to listen SET/Lowther but did you try to A/B your SET amp with more powerfull amplifier despite having Lowthers 100dB/W/m?

The ultimate tube electronics for me were always Manley and I had a chance to listen to Manley SET amps with Coincident Eclipce. I loved the sound but than I swiched for integrated EveAnna's 50W/ch amp and enjoyed much more.

As Sean stated that everything depends on funds invested into the product and almost every design can succeed in the right combination and it's realy fun for us to find our own equilibrium in funds vs. performance.

Marakanetz, perhaps you just prefer the sound of push-pull amps better than SET's. There is nothing inherently wrong with push-pull amps, and they have more power to kick the bass a little harder. My little Berning amp is actually a push-pull, using 6SN7 preamp tubes for outputs, and maybe that is why I don't feel that the bass is lacking like you say the single-endeds are. Whatever the reason, this little MicroZOTL kicks some booty on the bottom end. Really tight too.

Twl, about the 40 Hz rating. I've heard Brentworth single driver with Waytec SET (20 Hz rated) and the bass was disappointing.
Am I missing something because, take B&W Nautilus 804's for example,are rated at about 40 Hz but they seem to have more weight than the 20 Hz rated single driver? Is this a dynamics issue?

Cdc, the physics of speaker and driver design basically dictate that if you're attempting to reproduce (almost) the whole frequency range with just one driven element, you're going to have to give something up. It could be efficiency, dynamic range, extended bandwidth, optimized dispersion, etc., or a combination of some of the above. The payoff is supposed to be in the quality of "seamlessness" or "coherence" that comes from not dividing up the amp signal, not using different driver types or materials, and not intoducing lobing or phase anomolies, as well as possibly making an easier electrical load without a crossover for a low-powered amp to drive. In your above example, I'm assuming that the amps were also different, which would have something to do with what you heard (as would the rooms and setups), but yes, it's quite possible that a conventional multi-way speaker could exhibit superior bass dynamics. (BTW, what are the tolerances and conditions given [-3dB down or -6dB down? Anechoic, nearfield or in-room?] for the bass frequency response ratings you mention? If they're not the same, then you can't compare the ratings directly.)