Meet Dr. Joseph Pompei, Inventor of the Audio Spotlight - Part 1

Same principle as parametric sonar.

Sounds like the same way you make an interference hologram image. Very interesting though. I was going to discover this tomorrow! Day late..dollar short.

While I agree the technology is fascinating, im not sure how much I would credit the young 'Dr.' for 'developing' ulta-sound beams.Though I dont know who the original scientists were, the government has had (but never really used) this technology for two decades, developed as bio weapons to control or distort body algorithm and functional control. However, at least someone has finally been able to market this as a more sensable and profitable form of the technology for all the world to share.

Thanks for your comment, intellgently uneducated. Next week, CR4 will run a two-part story about Dr. Pompei's greatest rival, Elwood "Woody" Norris of American Technology Corporation (ATC). Part of that interview will address the history behind the technology in question.

FJP: Essentially, traditional sound sources cannot ever create tight beams of sound, so we create sound indirectly, using a beam of ultrasound. As the ultrasound travels through the air, the air itself causes the ultrasound to "distort" in a predictable way, creating audible sound in its path.

Im interesting in it. but I dont understand very well. He means audible sound and ultrasonic mutual converting?

or just make a filter which can focus sound at very narrow direction to propaganda efficiently? like an althorn which has a directional focus filter.

Not quite. Like audible sound, ultrasound is distorted as it passes through the air. The brilliance of Pompei's design is that he's found a way to use this natural distortion to make high-frequency ultrasound audible to the human ear - and in a narrowly focused way.

I browse the web site, it seems to develope a plate speaker with very narrow direction.

The plate speaker has been existing for a long time since last 80's, but no such narrow direction.

I want to knwo is how much response band wide is the "speaker"? no answer in the page.

Could he give us a reply here? howver, its a good invent.

For some background information on how directional sound technology works, check out today's installment of The Y Files.

This is, a brilliant, amazing technology, and I still cannot grasp, how it's done.

Would someone be kind enough to enlighten me on the physics of it, beyond the explained above?

If you shine a laser into an interference pattern which doesn't look like anything if you just look at it, will reflect a holographic image. The image is a result of the contrived interference pattern and not a actual reflection. So it is with this technology, I think. The sound you hear is a RESULTANT effect from a highly culminated high frequency beam that has been modulated (back engineered) to produce the intelligence you hear as a harmonic of the original frequency.

I don't know if I got it right or not, but it makes perfect sense to me! Anyone out there with a better explanation, please wade in.

So what's the common agreement on molecular wave propagation in 3D. It's supposedly omnidirectional from the source.

In other words: How does high-frequency modulation able to create coherent wave propagation.... Waitaminute...

Coherency and monochromism (single, narrow-band, coherent wavelength) in light waves are able to propagate in this weird manner, if laser is to be compared.

Alas, I still cannot grasp how laser does it. I'm moving in circles here. I need some sort of visualisation.

europium?

Are you available for this?

Am I an expert in this? No. Do I have an idea how it works? Maybe. If you look at the links provided by Moose and others, Holosonics is less forthcoming about how their technology works than is Norris. As for the physics of Norris' HSS, which uses two ultrasonic beams having different frequencies, his setup takes advantage of physical mixing of the two ultrasonic frequencies to get sum and difference frequencies. The difference frequencies are what the listener hears. Norris may either hold one frequency constant and frequency modulate the second using the audio input signal, or he may modulate both ultrasound signals. But in either case the results are the same. Nor is this technique new. Research into so-called Tartini tones began in the 1700s. Norris' technology takes two separate ultrasonic transducers, which can be spaced some distance apart, with both having fairly directional beams (the smaller the wavelength in comparison to the size of the emitting aperture, the tighter the beam), and where they meet, audible sound is heard. Or both sources can be co-located, producing audible mixing along the entire beam's length.

So, if one transducer is emitting a fixed 100 kHz tone, and the other is emitting a 102 kHz tone, where they meet will be heard a 2 kHz tone. The sum frequency, 202 kHz, is well above the hearing of even most bats. It is the difference frequency only that is heard. This also means that only half the energy going into the beams will have the potential to be heard. The other half is completely wasted.

Holosonics claims to generate audible frequencies by taking advantage of nonlinearities in the propagation of ultrasound through air. Their 'technology' web pages are sufficiently dumbed down to be of little help. However, where Norris' HSS uses at less two transducers, Holosonics uses one (or a tight array). Norris' HSS will actually seem to produce sound out of thin air (because it is produced only in the volume where the two beams intersect). But, judging by Holosonics beam profile charts, the sound is audible over much of their beam length. I also suspect the quality of the sound will vary over the length as well, as their technique depends on the nonlinearity of air at ultrasonic frequencies, and therefore the volume of air between the transducer and the listener will affect the results.

There (Audio Spot Light) as both beams interfere, is I guess the focused point. How do they keep the carrier beams so tight?

Is this normal for waves to behave in such medium? Can this compared in any way to the workings of a directional microphone or a satellite dish, having the focusing mechanism (Dish) to select from multitude of incoming directions?

The carrier beam divergence is a function of the carrier wavelength and the effective aperture. If the wavelength is small compared to the aperture width, the divergence will be small. The principle is exactly the same as is seen in optics.

Say, for example, you have a laser shining through a small, circular pinhole. If the pinhole diameter is on the order of a few wavelengths, the beam divergence will be large. You can see the effect on the beam divergence as the size of the so-called 'Airy disc' on a distant screen ('distant,' in this case, taken as meaning many wavelengths away). As you increase the pinhole diameter, the diameter of the Airy disc will decrease. Note that an Airy disc is not simply a single disc, but is composed of a central disc surrounded by progressively fainter annular rings. For the sake of discussion, one can consider the beam diameter (at a given distance) as being defined as the diameter of the first dark ring, or minimum. Approximately 93% of the beam energy falls within this disc.

The principles are exactly the same in the case of ultrasound. Holosonics says their emitters are roughly 12-18," (1/3 to 1/2 meter, roughly) depending on the model. In their write-up, they also say that the ultrasound's wavelength is on the order of millimeters. The emitter is the aperture, and is quite large when compared with the wavelength. This means, that in the "diffraction-limited" sense, the beam will be very tight. No focusing is necessary. This is a property of wave diffraction.

-e

Maybe I got it. So one could say that, in a way, the aperture dimension relative to the outgoing wavelength, is an active factor in the mechanism of modulation here.

? - would it make some sense?

? - if so, than it's actually a variation on the antenna-resonance theme

The aperture dimension vs emitted wavelength determines the divergence of the beam. This is independent of modulation considerations and only determines the size of the area in which the sound can be heard. It gives their 'Audio spotlight' its 'spotlight' characteristic only. Lower-frequency sound for a given aperture size would result in a larger beam, and as the wavelength approaches the size of the emitter, the beam would lose its 'spotlight' character and become more or less semi-isotropic.

It is the non-linear interaction between the ultrasound and the air that makes the ultrasound audible. What is so intriguing about their approach is that, generally speaking, nonlinearities produce higher-frequency harmonics, not subharmonics, and distortion. The distortion (greater than 50% in many prior attempts) lead to early abandonment of this approach. Pompei is not the first to try this.

I suspect that in Pompei's case, he is pre-distorting the audio in such a way that the non-linearities induced in the ultrasonic signal by air 'unravel' the pre-distortion in such a way that reproduces the intended signal in the desired way. And I'd bet those little boxes you see next to Holosonic's transducers contain some hefty DSP processors to perform this function, in addition to the amplifiers and ultrasonic-driver circuitry you'd expect with a device of this sort.

But back to your earlier question: the aperture vs wavelength determines the tightness of the beam. It gives it its 'spotlight' character, but only that. Pompei's innovation is in harnessing the non-linearity of ultrasound propagation in air to produce an audible sound. I'm definitely looking into this further, for no other reason than I like a good puzzle.

"...for no other reason than I like a good puzzle..."

O - I've got many applications in mind, practical ones for this, provided it comes within reasonable range of pricing.

So, to conclude, This DSP-powered frequency modulation of sort, is the mechanism to de-construct the audio signal, transport it to the target zone by aperture to wavelength proportion, to determine it's dimension and path, then comes interaction with the target medium, to reconstruct the audio signal, "extracted" from it's ultrasonic carrier "jacket".

In summary, I'd say it boils down to solving three, completely separate, problems:

1. Constructing a directional sound source. This part is easy.

2. Compensating for the distortion inherent in the "demodulation." Medium-hard. This is where the DSP comes in (if, in fact, this is what he's doing).

3. Leveraging the nonlinearity of the interaction of ultrasound with air to get an audible signal (distorted or not). Tough. This is where Pompei's real innovation lies, together with #2, above.

I do like a good puzzle. And a game of poker, if you take my meaning...

Everywhere whenever Yuval and Eroupium are at, there will be a hot discuss. here it is.
Eroupium always has unique, exclusive opinion of challenge

----3. Leveraging the nonlinearity of the interaction of ultrasound with air to get an audible signal (distorted or not). Tough. This is where Pompei's real innovation lies

I nearly agree to this opinion. at least I doubt the speaking about passing through air of a ultrasonic sound can produce a nonlinear distortion. what is this mechanism?
if there is nonlinear transform, there will be no audible sound to hearing.
interference is another incorrect speaking. because interference would be took palce at same frequencys, not same phase situation.
Maybe there is something like Doppler effect acting her. So that we can get sum and difference of the two wave.
I have an idea, could administrator like Moose pick a recording when interview and post here for us download to listen to?
in order that we can judge futher more.although Im out of it depth.

Its not lies, its real after visited their web. they have 111db sound level.

111 db SPL is a lot!

It's nearly the threshold of pain for the human ear!

yes,

every flate (shape) speaker has higher efficiency than traditional cone type speaker.

we bought the speaker (not that sharp directionone) as a decoration thing hang on the wall.

Is the sound fidelity (bass mid and treble) any good?

I dont know others, but ours is from 160 --18k. good hf than ordinary speaker but less at low frequency. so you have to add one woofer to enjoy your classic music, or some pop music.

But do carefully if you hope to buy on chinese market, becaue too many low quality speaker. only a little factories has OEM. permission

I 'm often cheated as well.

This is Huygens diffraction principle. When we will study interference phenomenas, it will be used.
But, speaker and speaker box (include mic) is another things for its directionality. For example, speaker cylinder (array). Its a huge topic, we can only cut long for short here.( continue below...)

Not quite the same thing. To create a hologram, you illuminate a photographic plate (for example) with a monochromatic reference beam - usually laser light passed through a diverging lens. You also illuminate your subject with a second beam. Where the reference beam and the reflected light from the subject meet at the photographic plate, they produce an interference pattern. The plate records this pattern and, when developed, all you see is the composite pattern. It usually looks like a smudge.

However, if you now illuminate the developed plate with the reference beam, the recorded interference pattern and the reference beam together recreate the wavefront that originated from the subject, and hence, you see exactly what the subject reflected; including all phase information. It is, essentially, a 3-D reconstruction of the wavefront as was seen by the photographic plate with the original subject present. A hologram.

But this is not what Dr. Pompei is doing here.

Europium! Thanks, along with the Yuval discussion this was very informative and a great explanation.

You're welcome!

Note that in the case of the hologram, the process is invertible. That is, if you illuminate the developed plate with only the wavefront from the original subject, you will get the reference beam's wavefront! And if you illuminate the photographic plate with both the reference beam and the original subject's reflected wavefront, you will get the smudge. Nor are you limited to just two sources - the reference and the subject. You can use any number of sources to produce the interference pattern on the photographic plate and, as long as all but one are present after you develop the plate, you will get the missing wavefront. As you can well imagine, this has applications for cryptography. Two or more carefully-constructed wavefronts could represent keys, and the resulting reconstructed wavefront represents the encrypted data, image, or whatever.

The wavefronts need not be 'images', as such, but other patterns, as well. And since the reconstructed wavefront looks different from different angles, you can encode information onto the plate that varies depending on viewing angle. True holographic storage has huge potential for storing enormous of data in compact form on a 2-D plate, but it need not stop there. Consider the potential of 3-D holographic storage where the particular hologram of interest depends on a specific depth inside, say, a crystal. And if you precisely rotate the crystal (about any of its axes, or a combination of them. And consider that the shape of the crystal need not be a cube; it could be a polyhedron or even a sphere), you get a completely different data set. Depending on the resolution of the storage, the wavelength used, and so forth, it may well be possible some day soon to store the entire contents of the Library of Congress in a crystal the size of a sugar cube.

And the crystal could be assembled a layer at a time, with precisely introduced defects to create the composite database. In this way, it could be mass-produced.

But we're getting off-topic here (something I almost never do, as anyone here will tell you).

"...this has applications for cryptography. Two or more carefully-constructed wavefronts could represent keys, and the resulting reconstructed wavefront represents the encrypted data, image, or whatever..."

I know it has been used or at least tried ever since 1996 or 7 or so.

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/6572/17626/00817849.pdf (You must have an IEEE membership or a subscription to Xplore to open this link)

http://www.springerlink.com/content/q7hb183b2dj5qm0x/

to name a couple

Hello, Yuval. This page from the Holosonics web site may help a bit.

Part 1 of the interview with Joe Pompei's competitor, Elwood "Woody" Norris, is now live on The Y Files.

http://cr4.globalspec.com/blogentry/2185/Part-1-Meet-Woody-Norris-Inventor-of-HyperSonic-Sound-HSS

I have an idea, could administrator like Moose pick a recording when interview and post here for us download to listen to?
in order that we can judge futher more. although Im out of it depth.

anyone neednt suspect I will have any attempt. I just take interest to it and this is good way to testfy if the item is as useful as description.

Sound resources of a speaker is somethng like a piston moving around in cutting magnetic field, which exciting vibration film to give out sound. The sound can radiate as a sphere wave, If we use only bare speaker to listen to music, there might be certain frequencies of sound short took place. so we have to use an infinite large board or a box to stop sound from its short circuit. To obtain a direction, we can use this diffraction principle, let sound wave pass through different path and in form of different phase to get together, so that we can achieve required directionality. This is sound lens focus. very like optic focus. The longer wavelength, the sound has, the large size the focus lens will has. Thats why we used to make hf lens rather than low lens. likewise inverse phase box etc.

whereas flate speaker work different principle from cone speaker we use to use(both electromagnetic and static electric or electret speakers). It made of special material, a bit like a "alveolate (cell?)" surface fulfilled all the board. It produced same phase vibration both sides of the board. So we neednt a box to prevent from short sound. and have a good direction. it doesnt observe sqare inverse ratio law in air diffuse.

experence show us, the more hf the sound has the fast attenuation will be got,We all know,when we dealed with ultrasonic instruments, both for medical and industry, we have to use a coupler between the ultrasonic probe and material where we are detecting, the coupler agent could be water, oil or some organic liquid to prevent ultrasonic wave from strongly attenuation in air media. thus, we doubt why they use ultrasonic as transmitting media (Might it also not comply with frequency attenuation ratio law?). We admire ultrasonic can easily get a more better direction than ordinary audible wave.

In one words, we should distinguish what is spot sound resources, what is surface sound resources before result in wave directionality.

Dear Guest,

Sometimes people may consider finding a way to move away from their apartment or house, being annoyed by abusive neighbours.

The general impression one might have, reading your account and given it's absolutely true, is that someone in your neighbourhood got hold of this Audio Spotlight system, and being ill-natured/bored/abusive, decided to experiment in driving you crazy, in order to satisfy their sick tendencies.

I wouldn't tell you to ignore it as it might very well be impossible technically, but some stealthy investigation may be in order to pinpoint the perpetrators, and bring them to justice.

Such investigation is possible with the aid of private investigators, and given that the Audio Spotlight system has known range and characteristics typical of this technology.

I wish you luck in bringing those sick experimenters to justice, and remember, as last resort, maybe moving away from there, may snatch their victim from their eager reach, leaving them to search for another, which if and when they would complaint too, may convince the local authority to finally snap, and do something about it.

I find it very sick that people are avoiding this perticular document about how cults and organized crime can kill using this device. Maybe someone you know or love,?....statnding in the way of public education?,...

Various ways to hurt someone (possibly even kill someone) with audio spotlight

Notice how these crimes coexist with "litte" crimes to help hide a semi-expensive murder using audio spotlight, and a

gang of people with not much else to do, many trianed in psychology, and acting (computer hacking and spyware too)

1. Point the device out your 2 story window and call people racial names, and make reference to their actual surroundings, and clothing, to make it more realistic. This can be used in and around drug dealers to create violence. An introduction can even be given to a group of street people about another, simply by transmitting "John has on the burgundy jacket" (substitute the victims actual name) to introduce the victim to a pack of well beaten up homeless drug addicts. You may increase the probability of getting this person beat up or even shot. These drug dealers could be angered further by suggesting to them (still pointing it down from window ledges, working in groups, working with cell phones) that each other had found their lost drugs on the ground or stolen their drugs. It may surprise you how easily some of these people are angered in run down homeless areas, especially when they have been kept all night, by the device in question, if the rooftops, or 2nd story windows are available). Much smaller versions of this are most likely available, a person could even "hide out" in the bushes and do this to someone, or from a parked car) if they were "skilled" enough, while they sleep outside on a park bench, for example)

2. Pointing at the window. Pointing the device at the window (if you can get a clear and "hard to notice" shot at the window)

can keep a person up for weeks at a time (unless they find good enough ear plugs). This can lead to job loss, which in turn can lead you to living in a run down , drug infested area, which can bring you closer to being murdered with audio spotlight.

3. Moving in beside someone - The sound can be cast through holes in the walls. If you really want to kill someone with audio spotlight, and they live in an apartment, you may have an easier time, making someone's apartment hellish for them with psychological abuse, in front of mirrors and in the bathrooms is a good place to try to break someone with psychological abuse. It is also true that this sound reflects, so if you have a decent schematic of the house (upstairs apartment) you can point the sound from the hole (that must be disguised, in many cases) to bounce around "somewhat". video surveillance

can also be done through the hole, and in turn make the psychological abuse more effective. Hiding the hole is most likely easiest in the corner of the ceiling, or behind anything that patrudes out from the wall. All of these variables narrow down the possibility of killing someone with audio spotlight. Meaning never touching them physically.

4. Taking over the WORKPLACE is very difficult, may involve a break in (or a dress up repairman scam), and a device placed into a high corner, at the right angle for above cubby hole walls, and possibly discussed as something else, like a "weird" surveillance camera with a radar like back (when their tech is more low tech). Make sure to look in the work place for obvious looking "radar" shapes. In a large "high tech" office, this may just fit in normally and go unnoticed. Often a rumor could be spread through the office about what it was for, but most likely this radar is going to have no owner, and the detachment of it's transmitter, will be an early warning sign for them, because the handshaking signal will be broken.

5. Moving violent homeless people to an area (another different run down area) may, sickly enough be accomplishable with a "bread crumbs" trail of drugs, like crack cocaine, and a couple of dress ups, like crack heads, in which the rumor is spread to them that the other "fake homeless people" that lived on the other corner or location were always dropping all kinds of crack. This could be even done through a gang member junkie , paid to go do drugs with the more violent junkies, supplying him/her with the drugs to make friends, and lying to them telling them that there was a reason to move to a location , for example, drugs were found on the ground often there. This would be made real by dropping real drugs, or hits of crack there) to try to coax a set of violent druggies to a certain location, in which the murder victim lived. Then you can execute the audio spotlight crimes.

6. Taking over a speaker in a radio could most likely fit a version of the "audio spotlight" if shelf speakers were in a room, but were not often used. A an attached radio

or stereo could be broken, by a break in, and the audiospotlight "mini" placed into the old speaker.