To map out the physics of 'difference frequency generation' sounds like science. To leave an implication of general use of resulting 'audible enclaves' for humans in dynamic, non-anechoic environments sounds (to me) like fantasy.

But such seems to be the claim. . .

"Researchers created sound that can bend itself through space, reaching only your ear in a crowd" article: https://theconversation.com/research...a-crowd-252266


Good luck with that one,

Ray H.

Footnote: https://www.pnas.org/cgi/doi/10.1073/pnas.2408975122

Seems more speculative than proof of concept: laser-pointer like propagation beaming, deriving meaningful audio from beat frequencies, sounds more like a Russian hypersonic tactical weapon ?

Bluetooth and similar RF fed earbuds (think in-ear monitors) might be more pragmatic...but keep us all briefed as developments arise.

i would love to hear a pa that creates personalized audible enclaves via self-bending ultrasonic beams...

[huge step up from conventional 'more me' boxes]

...although: this would give the term pa an entirely new meaning: personal is the new public! - perhaps quite appropriate in these times?

Interesting, that is probably something else than what those "musem" directional speakers use?

One friend has a company selling those around the world to galleries, museums and such...

I mean this: https://www.holosonics.com/

and this is my friend's company: https://www.ultrasonic-audio.com/

(there are other companies, too, using the same(?) or similar technology)

I guess what you shared is something different?

This technology has been deployed for crowd control for many years by various regimes.

Not pleasant.

Ah, I read more - the difference is that with those "parametric array speakers" the sound still travels along the entire (focused sound beam) path, while what they propose is to send the sound to an exact point in space... which is, wow... interesting.

Not for music, I guess, but for many other applications (and abuse, I'm sure).

Yes, audible enclaves is a different functional claim than narrow beam (see image from article, attached). “We use two ultrasound beams at different frequencies that are completely silent on their own. But when they intersect in space, nonlinear effects cause them to generate a new sound wave at an audible frequency that would be heard only in that specific region.”

Actually, what I wonder now is - if there would be a way to construct "speakers" or devices that would send the full range signal in such a way to your preferred listening spot, without the interaction of the whole room - and not bothering anyone else...

I can imagine that you could listen at "concert" volume in your flat, without annoying the neighbours and without your untreated small room causing bad sound and also a different experience than having headphones on.

Another consideration - will this be possible with full spectrum, also bass and subbass, will it also be "visceral"- will you "feel" the sound bodily at that point in space, like when you listen to live music or through the speakers? I guess, if the "audible enclave" is at the point where your head is - you won't feel the music in your gut, chest and bones... But could still be interesting...

I’m simply going to express a strong preference for sound propagation through air, filling the space it’s being generated in….along with boundary reflections, refraction and air absorption of high frequencies with distance….and all detected by my ears, as it’s always been.
I have no affinity for nor interest in the mooted manipulations…though it might gain a PhD for an intrepid researcher...

Their implementation of 125 Hz to 4 kHz (6 octave bands) might sound more like it was recorded with ribbons—and you know I mostly prefer modern SDCs. Still, I’m certain they will do better over time.


. . .but, I can’t sit in one place very long.

Ray H.

i would want to hear a practical application.


[...in order to assess whether the technology is reasonably suitable for 'musical listening', what the long-term effects on people would be, how the level can be dynamically adjusted, within what range, what interference (possibly also in other senses) is to be expected, how cats and bats in the vicinity react to it etc.

and would it be possible to use this technology if the frequency range needs to be further extended, several targets are close to each other or move around in the listening room? - i can't imagine how the latter problem could be solved with reasonable effort, but then, modern radar systems can detect/'follow' an insane amount of objects at the same time which brings me to another question: did the fr of the sound carriers/self-bending beams get mentioned anywhere in the paper?]


'further investigations are necessary'...

My very first mental image reading of the research was that of a disoriented bat flying through the space—crashing somewhere in its confusion.

The researchers project practical applications are still quite some distance into the future, which is reassuring: ‘cause I hope de bat he don’t come out and fly in me face tonight!


Haven’t got time for the pain,

Ray H.



Q: “did the fr of the sound carriers/self-bending beams get mentioned anywhere in the paper?”
A: No, only the proof of concept’s implemented range. See footnote link in OP.

ultrasonic projects mounted fore and aft on a submarine, being able to project a false sound image some distance away from actual location.

Can imagine similar military uses on land; misguiding motar/gunshot locators and such.

In a civilian use, can imagine it'd be a marketable gimmick to be able to project these sound pockets round a convention hall or such.

The novelist Ian M. Banks loved the idea of sounds pockets - used them throughout his sci fi novels.

See “Supporting Information” for a video demo and audio download link toward the bottom of their Abstract’s page.

Repeated for convenience : https://www.pnas.org/cgi/doi/10.1073/pnas.2408975122

poor animals! - the quote in my signature remains relevant...

i admit i couldn't stand the rather vague blabla and hence only skimmed the text...

pls let's NOT get into (potential) military application...

...as i have spent the better part of the last year capturing acoustic and radar signatures of various flying objects, no kidding!

maybe you should team up with the researchers?

now we're talking!