Imagine sound directed just at your ears

[Graham849]

Researchers created sound that can bend itself through space

"In our work, we used ultrasound as a carrier for audible sound. It can transport sound through space silently – becoming audible only when desired. How did we do this?

Normally, sound waves combine linearly, meaning they just proportionally add up into a bigger wave. However, when sound waves are intense enough, they can interact nonlinearly, generating new frequencies that were not present before.

This is the key to our technique: 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."

 

[gwing]

Generate a "new sound wave" or generate a sound wave that is actually something like the original sound?

 

[Graham849]

Generate a "new sound wave" or generate a sound wave that is actually something like the original sound?

further down the article they write "This isn’t something that’s going to be on the shelf in the immediate future. For instance, challenges remain for our technology. Nonlinear distortion can affect sound quality. And power efficiency is another issue – converting ultrasound to audible sound requires high-intensity fields that can be energy intensive to generate."

 

[dedobot]

I know the politic is no-no, but can't constrain to mention the recent claims that in an Balkan state , against the protests during past weekend is used "ultrasonic" weapon for crowd control .

 

[gwing]

I know the politic is no-no, but can't constrain to mention the recent claims that in an Balkan state , against the protests during past weekend is used "ultrasonic" weapon for crowd control .

When I see "ultrasonic weapon" like this in the press I always assume this is a factual inaccuracy and they really mean "unpleasantly high pitched" rather than a true ultrasonic that can't be heard.

However I was struggling in vain to think of a plausible practical use for this recombination ultrasonic technology. Frighteningly, it's use as a crowd control weapon would seem a likely candidate for that, I like the idea of it even less now.

 

[dedobot]

When I see "ultrasonic weapon" like this in the press I always assume this is a factual inaccuracy and they really mean "unpleasantly high pitched" rather than a true ultrasonic that can't be heard.

However I was struggling in vain to think of a plausible practical use for this recombination ultrasonic technology. Frighteningly, it's use as a crowd control weapon would seem a likely candidate for that, I like the idea of it even less now.

Yes , journos claims often are incorrect. In other reports it was described "directed sound" non-lethal weapon.

P.S.
For other practical use I again can think only in military applications -like misleading your opponent about your position.

 

[Talisman]

In a crazy attack based on an ultrasonic cannon I imagine a huge crowd of people looking at each other doubtfully without understanding what the attack is and then a small group of audiophiles over sixty who run away covering their ears with their hands....
Sorry I couldn't resist

 

[gwing]

In a crazy attack based on an ultrasonic cannon I imagine a huge crowd of people looking at each other doubtfully without understanding what the attack is and then a small group of audiophiles over sixty who run away covering their ears with their hands....
Sorry I couldn't resist

Wouldn't that be the other way around with adolescent activists fleeing holding their ears while us ancient audiophiles blithely stand there wondering what all the fuss is about?

 

[Vladimir Filevski]

This is the key to our technique: 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."

Yesteryear (yesterdecades, really!) news. Directional speakers working on ultrasound principle are real products, for years:

https://waves-system.com/en/directional-sound/
https://waves-system.com/en/produit/hypersound-mono-pack/
https://waves-system.com/wp-content/uploads/2024/04/Hypersound_Data-sheet.pdf

https://www.ultrasonic-audio.com/products/acouspade-directional-speaker/

https://molitor-produkte.de/en/product/molitor-fsc1-b2-g/

https://www.directionalaudio.co.uk/products/akoustic-arts/

 

[Hayabusa]

Researchers created sound that can bend itself through space

"In our work, we used ultrasound as a carrier for audible sound. It can transport sound through space silently – becoming audible only when desired. How did we do this?

Normally, sound waves combine linearly, meaning they just proportionally add up into a bigger wave. However, when sound waves are intense enough, they can interact nonlinearly, generating new frequencies that were not present before.

This is the key to our technique: 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."

This technique is not new..

60's

https://en.wikipedia.org/wiki/Sound_from_ultrasound

 

[Petrushka]

Wasting power to achieve an effect sounds like Tesla’s (the person) dream of wireless power.

 

[gwing]

Moral of the story - the danger is already with us, take a good large placard with you next time you're on a demo

 

[Talisman]

Wouldn't that be the other way around with adolescent activists fleeing holding their ears while us ancient audiophiles blithely stand there wondering what all the fuss is about?

They say that if a joke needs explaining, it was obviously a bad joke.
The joke was that there are 65-year-old audiophiles who tell how they can hear the difference between a 22khz filtered dac and the unfiltered ones...

 

[Audio Science Pal]

I have not experienced the system but have read good things about it. https://holoplot.com/insights/case-studies/msg-sphere-case-study

 

[kemmler3D]

Have been reading about this for years, but last I heard the distortion was still really high. Since they are forcing air to work in a nonlinear way I assume it's hard to get pure tones (and no overtones) out of it.

 

[Holmz]

They say that if a joke needs explaining, it was obviously a bad joke.
The joke was that there are 65-year-old audiophiles who tell how they can hear the difference between a 22khz filtered dac and the unfiltered ones...

Some of us got it, and it was brilliantly executed.
Ciao

 

[Philbo King]

Researchers created sound that can bend itself through space

"In our work, we used ultrasound as a carrier for audible sound. It can transport sound through space silently – becoming audible only when desired. How did we do this?

Normally, sound waves combine linearly, meaning they just proportionally add up into a bigger wave. However, when sound waves are intense enough, they can interact nonlinearly, generating new frequencies that were not present before.

This is the key to our technique: 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."

I remember DARPA working on something similar in the late 90s.

They've pretty well scrubbed their past projects off the web (and I can't blame them). So I don't have a link to it.

 

[punosion]

Somewhat related, I have one of these kicking around:

https://www.kickstarter.com/projects/richardhaberkern/soundlazer

I’ve been wondering for a while what it would look like on the Klippel…can’t decide if the dispersion graphs would be boring or crazy (could be weird spurious stuff going on with microphone or boom interactions that we haven’t seen before), but the response graphs definitely would be interesting.