Ring radiator tweeters - the future?

Why no tweeter?

Read the paragraph "The Quest for that Old-time Religion".

There was a time, two generations ago, when the full-range cone driver reigned supreme. In an age when the radio console together with the shellac 78-rpm record defined audio quality, a frequency range of 60 Hz to 9 kHz was about as wide a window as was needed or desired for the enjoyable reproduction of available source material. If anyone dared to open the window any wider – especially in the treble - they ran the risk of exposing gremlins such as needle scratch and other high-frequency hash and noise. With the advent of the high-fidelity phenomenon in the 50s, the audio industry moved inexorably toward multi-way loudspeakers, such as two and three-way designs, as a means of expanding the bandwidth at the frequency extremes. The advertising campaigns/hype at the time were so effective, that for many people Hi Fi became synonymous with bandwidth. Many consumers expected to pay a premium for a high-fidelity loudspeaker basically because of its increased bandwidth. Even today, many audiophiles and audio engineers seem convinced that the road to hi-fi heaven lies at the frequency extremes. Of course, music lovers know that this is patently false, and that the emotional content and drama of live music have little to do with the frequency extremes.

Multi-ways effectively cut the music in half. Do you really think the speaker designer can put it back together again? Even 1st order is only in the small sweet spot.
People commonly ask, why is a speaker $10,000 for $200 worth of drivers. IMHO the price is for the expertise of the designer making the drivers work together. A very tricky task as the x-over can't just be designed on paper, from what I have read from the guys at madisound.com. You have to tweak it by ear over and over again to make it sound right.

As stereophile wrote on Krell Resolution 1 speaker:

I must assume that Mikey's thinking the Resolution 1 sounded a bit "rich" in the upper bass is due more to the woofers' restricted passband. (The more you limit a drive-unit in the frequency domain, the less well defined its output will be in the time domain.)

Running a driver full range with no high or low-pass x-over is the way to go or timing will be off.

"Fact is most single driver systems have worse timing errors than properly designed multi-element speakers.
" Cinematic_systems.
Why is this??
You have multiple drivers that are not time or phase coherent operating from different points in space (vertical and depth). Some, like Revel, are run completely out of phase. As Stereophile said, limiting bandwidth causes further timing errors.

How can such a speaker have correct timing? Where is your technical information to back up your statement?

"99.999999999999999999% of the public anytime you get more bass".
True, and most audiophiles can't get beyond detail and soundstaging, not to mention boomy bass. It's a preference, no absolute right or wrong.

"Most good speaker design manufacturers are obsessed with either bass or midrange or simply obsessed."
Judging by bass boost in Wilson, Krell, Paradigm (10db boost in Atoms), Monitor Aduio, B&W, etc. etc. I'd go back to your 99.999999 comment.

"Single driver speakers are not the answer, most are inferior for the very reasons you find flaws in multi-element designs"
What flaws are those?

"As single driver system remain only viable to fringy audiophile types who don't listen to powerful large scale or popular music"
IMHO, you need to add "IMHO" to that comment.

I'm always interested in learning. But so far you have provided nothing but your personal opinions and, IMHO many of those aren't even accurate.