what are the thoughts of stand alone super tweeter

As noted previously, Murata is rather vague about the internals of their device. If there is no electrical crossover then the cutoff is being handled by the inherent mechanical parameters of the tweeter. There will still almost certainly be output under 15KHz since drivers don't just stop working at a precise frequency. (Ever watch a woofer move with a warped record? With one warp in a record that is about 0.5 Hz but the driver is still trying.)

I've got some fairly sophisticated audio processing software (Adobe Audition) that I used for mixing and editing and it is interesting to play with the several different equalizer options. One can create a nearly infinite number of slopes and crossover points and easily apply them to real music. Frankly, there is precious little to actually "hear" as music when one does steep slopes above 10KHz.

I applied a variety of curves to some material to model possible Murata outputs. I can guarantee you that with a curve set around 10KHz for cutoff there isn't much music to hear. Yet if one applies the inverse curve to the same music, the sparkle and air disappears. And all of that happens with no output above 20KHz since I used CD material.

In short, I was able to duplicate the effect you talk about by limiting the output to above roughly 10KHz but yet without using any super-high frequencies.

I know the super-tweeters have a following. One doesn't have to have uncontested exotic scientific theories at work in order to enjoy the effects of a piece of audio equipment.

As noted before, if the original poster is interested in one of these, he simply needs to try it. If it gives him more listening pleasure then he doesn't need to worry about whether it is ordinary high audio frequencies at work or super high ones.

I didn't say that the output of the Murata only dropped below 15K Hz. It is dropping sharply at 15K. Yes, I suspect it is the mechanical characteristics rather than a crossover and thus my speculation about the Townshends.

I doubt seriously if you can duplicate the effects of the Muratas or other supertweeters without frequencies above 15k Hz. I do agree that the original poster should try them.

...without frequencies above 15k Hz.

That is not what I said.

I said without frequencies above 20KHz from a CD (actually 22,050 Hz from the Nyquist theorem but there is only 1/10th an octave difference between 20K & 22K.)

Arbitrarily decreasing a number I used by 5,000 isn't a very on-point response. You in politics? ;-)

However, even with non-CD material, one has to wonder where the super-high frequency info comes from. The majority of microphones used for professional recording don't have response past 20 KHz and many only get to the 15KHz or 17KHz range.

Anyway, having been exposed to these devices over the years I remain a skeptic that any significant portion of the effect these devices have is due to energy above 20KHz.

Obviously, others disagree.

Yes......

Let me throw this out for speculation/discussion.

Many reviewers and others report super tweeters to be an improvement. I have never heard speakers with them so I have no informed opinion.

They operate at frequencies we can't hear. So there shouldn't be any problem with integration with the main speaker since we can't hear them anyway.

My speculation is that they operate simply by having their frequencies interact with the frequencies that we do hear. In other words, the compression and rarefaction of air from the sound waves of the main speaker is added to or subtracted when it meets the wave of the super tweeter. So we're just altering the frequencies of the main speaker.

In other words, it's just another type of a tone control. Right? If not, then what does it do?

I'm not trolling here. I'm just trying to figure out how these things work.