Not that I'm here to just slam Klipsch or shill B&W, Bob B., but I have to disagree about your assessment of the 801's dymanic capabilities. First, let me say that I am a big promoter of the idea of higher speaker sensitivity, and would not personally buy a speaker with less than at least "average" sensitivity (86-87dB range), and would like my next pair of speakers to go even higher if possible. I also think that increased system efficiency is more responsible socially from an energy consumption point of view. I myself don't want to own monster power amps, to deal with their size, heat, and cost, or to feel that I need to play my speakers at concert levels just to make them wake up and come alive.
But potential system dynamics have to do with more than just speaker sensitivity. If you have the power to feed your dynamic monitors, and they can handle it, then more than satisfactory results are possible. I have heard systems based around 801's, or Wilson Watt/Puppy's, for instance, that can virtually punch the listener in the ear (and the gut), because sufficient power was available to drive them. One could make the augument, however, that the use of such high power - or the design of the drivers to be able to make the necessary excursions - might possibly compromise some other, more subtle aspects of the sound in a trade-off to get those astounding dynamics.
I was glad to see that Thiel brought out their newest speaker, the smallish 2-way floorstanding CS 1.6 (which sound fabulous, BTW), with a much higher, for them, sensitivity of around 90dB. Maybe this will point the way of the future when Thiel finally introduces the long-awaited replacement for the standard-setting CS 3.6 (I hope they banish the utra-low impedances, too).
Whether they employ horns or not, I believe speaker makers should make a serious effort to provide products that pay attention not just to response characteristics, but also to higher sensitivity, moderate-phase and -value impedances, and just as importantly, flatter overall impedance curves, so that audiophiles can more successfully utilize a wider range of amplifiers with most speakers. Amp designs, tube or SS, that do away with using negative feedback to achieve conventionally acceptable damping and output impedance figures can, in my experience, "un-box" the sound to a similar degree as high-efficiency speakers can - but at the potential cost of more colored response, when used with typical impedance-characteristic speakers (horns included).
For me personally though, it's more the dispersion properties of horns that keeps me away from them (I like mine wide), than any preconceptions about "colored" sound. I guess I weight this preference more heavily in my choice than superior dynamics, but that's obviously not going to be right for everybody - and I would of course love to have it all (but can't afford it!). Happy listening :-)
