Speaker sensitivity vs SQ

I have owned all manner of speakers--conventional sealed box, bass reflex box speakers, electrostatics, planar magnetics, etc., and all types of speakers, with varying efficiencies, can deliver decent sound.  But, over time I have gravitated toward high efficiency speakers because they can be utilized with my favorite amplifiers (most of which are low-powered tube amps) and because they tend to deliver superior dynamics.  I know there are theoretical reasons for this--low power being delivered to the driver for any given volume level means less heating of the voice coil (heating causes an increase in resistance that then reduces the ability to deliver more power, in other words the driver output does not increase linearly with increase power (i.e., dynamic compression)--but, whether or not this is true, I tend to find higher efficiency speakers more dynamic sounding).

I currently own a system with twin 12" woofers in an Onken cabinet, midrange supplied by a compression driver/horn combination, and highs delivered by a bullet tweeter.  Horn systems like this tend to be large in size, which is why the industry went away from these systems, particularly when stereo required installing two speakers (and HT requiring even more speakers).  I don't think it was sound quality that killed horn-based system.

bdp24,

I agree with you about the relative merits of Soundlab electrostatic speakers vs. the Altec Voice of the Theater speaker.  The Altec tonal coloration is way too unnatural for my taste as well.  At one time I considered buying Soundlab speakers.  But, while most of the commercially available compression driver systems suffer from too much tonal issues for my taste, I've heard many custom systems that sound very good; I ended up with such a system.

I feel the same way about many other high efficiency speaker types, such as full range single driver systems.  I ultimately don't like their tonal balance and rough frequency response (notable exceptions are Charney Audio and certain Voxativ models).

I like some systems that use "fullrange" drivers as wide range drivers in multi-way systems.  In some, a woofer supplements the fullrange driver, in others, a tweeter is added on top.  An example is the Soundkaos Model 42 (fullrange driver plus a Raal ribbon tweeer on top).  My favorite system utilizes an old Jensen M10 fieldcoil driver (13" fullrange driver) in an open back cabinet (open baffle) operating full range, but with a first order high pass crossover to a tweeter supplementing the single driver (the system I heard had a Jensen RP 302 tweeter, but, I am told that a Western Electric fieldcoil 597 driver is better).

lalitk,

I've heard the Canterbury and other coaxial Tannoy speakers and liked what I heard.  I just did not consider them in the discussion because they I did not consider them to be a single, full-range driver.  But, they are certainly great sounding examples of fairly highly efficient speakers that are easy to drive and can be run with low-powered amps.  I also agree they are quite nice to look at too.

I have a friend who is now in the process of building a system using the coaxial Altec 604 drivers from Great Plains Audio.  At one point, he considered an Onken cabinet, but, the available designs for this driver specify a 360 liter cabinet (one and half times the size of the Canterbury's Onken cabinet) and this was too large to be practical.  Too bad, I like the sound of Onken bass reflex speakers.