Highly Directional Audio Paper?

[amdx]

I'd like to see this paper, anyone now how to locate it?

Mike

Dr. Joseph Pompei wins Technology Review's Award
for Audio Spotlight Directional Sound Technology



The Audio Spotlight system uses nonlinearly propagating ultrasound to
create highly directional beams of sound in mid-air, which can be "shone"
and "directed" much like light. Dr. Pompei was the first in the world to
develop the mathematics and advanced engineering that allowed sound to be
created literally from thin air with sound quality and reliability rivaling
traditional loudspeakers. He presented his first paper and demonstration in
1998 to the Audio Engineering Society, and was met with a standing ovation
from the world's top audio professionals. Once the audio industry was shown
that such a system could actually work - and once Pompei published a paper
showing exactly how, several other groups have done their best to copy the
device, but none have succeeded. "I'm happy that Technology Review correctly
recognized me as the true inventor of the technology," says Pompei.

 

[Eeyore]

The Audio Spotlight system uses nonlinearly propagating ultrasound to
create highly directional beams of sound in mid-air, which can be "shone"
and "directed" much like light.

Beams of *ultra*sound.

And what damn use is that to anyone ?

Graham

 

[Vladimir Vassilevsky]

I'd like to see this paper, anyone now how to locate it?

Mike

Dr. Joseph Pompei wins Technology Review's Award
for Audio Spotlight Directional Sound Technology



The Audio Spotlight system uses nonlinearly propagating ultrasound to
create highly directional beams of sound in mid-air,

I can't help you with the paper. However this technology is no new. The high
intensity ultrasound is modulated by amplitude. It is demodulated in the air
due to the thermal nonlinearities, so you can hear the sound. The main
problem is that the required intensity of the ultrasound is too high to meet
the safety requirements. So this technology can't be deployed for the
general purpose use.

Vladimir Vassilevsky
DSP and Mixed Signal Consultant
www.abvolt.com

 

[Ron Capik]

I'd like to see this paper, anyone now how to locate it?

Mike

Dr. Joseph Pompei wins Technology Review's Award
for Audio Spotlight Directional Sound Technology

Don't know about that paper but you might also check out:
< http://www.atcsd.com/pdf/HSSWHTPAPERRevE.pdf >


Later...

Ron Capik
NJ Pinelands Cultural Society
< www.AlbertHall.org >
--

 

[martin griffith]

I'd like to see this paper, anyone now how to locate it?

Mike

Dr. Joseph Pompei wins Technology Review's Award
for Audio Spotlight Directional Sound Technology



The Audio Spotlight system uses nonlinearly propagating ultrasound to
create highly directional beams of sound in mid-air, which can be "shone"
and "directed" much like light. Dr. Pompei was the first in the world to
develop the mathematics and advanced engineering that allowed sound to be
created literally from thin air with sound quality and reliability rivaling
traditional loudspeakers. He presented his first paper and demonstration in
1998 to the Audio Engineering Society, and was met with a standing ovation
from the world's top audio professionals. Once the audio industry was shown
that such a system could actually work - and once Pompei published a paper
showing exactly how, several other groups have done their best to copy the
device, but none have succeeded. "I'm happy that Technology Review correctly
recognized me as the true inventor of the technology," says Pompei.

it might be available from aes.org, but they may take money from you
for downloading articles



martin

 

[MooseFET]

Beams of *ultra*sound.

And what damn use is that to anyone ?

You can hear the demodulated result from nonlinearities. They
modulate the untrasound with what they want you to hear and point the
beam at you. You can hear the sound but the person beside you can't.
The sound sounds as though it is right inside your head. These
systems are being deployed with police for riot control and other
situations where the cops may want to talk to one person and not let
another hear.

 

[Tim Wescott]

You can hear the demodulated result from nonlinearities. They
modulate the untrasound with what they want you to hear and point the
beam at you. You can hear the sound but the person beside you can't.
The sound sounds as though it is right inside your head. These
systems are being deployed with police for riot control and other
situations where the cops may want to talk to one person and not let
another hear.

So those people who complain about the voices in their head that are
beamed by the government -- they're not kooks after all?

This would explain why the tinfoil hats don't seem to help much.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

 

[amdx]

Beams of *ultra*sound.

And what damn use is that to anyone ?

Graham

See http://holosonics.com/press.html for some >advertised< uses.
Mike

 

[Jim Thompson]

See http://holosonics.com/press.html for some >advertised< uses.
Mike

You will note _where_ it was invented ;-)

...Jim Thompson

 

[Eeyore]

You can hear the demodulated result from nonlinearities. They
modulate the untrasound with what they want you to hear and point the
beam at you. You can hear the sound but the person beside you can't.
The sound sounds as though it is right inside your head. These
systems are being deployed with police for riot control and other
situations where the cops may want to talk to one person and not let
another hear.

*ARE* being deployed ? Any evidence for that ?

I doubt you can steer any ultrasound beam that accurately anyway.

Graham

 

[Salmon Egg]

I'd like to see this paper, anyone now how to locate it?

Mike

Dr. Joseph Pompei wins Technology Review's Award
for Audio Spotlight Directional Sound Technology



The Audio Spotlight system uses nonlinearly propagating ultrasound to
create highly directional beams of sound in mid-air, which can be "shone"
and "directed" much like light. Dr. Pompei was the first in the world to
develop the mathematics and advanced engineering that allowed sound to be
created literally from thin air with sound quality and reliability rivaling
traditional loudspeakers. He presented his first paper and demonstration in
1998 to the Audio Engineering Society, and was met with a standing ovation
from the world's top audio professionals. Once the audio industry was shown
that such a system could actually work - and once Pompei published a paper
showing exactly how, several other groups have done their best to copy the
device, but none have succeeded. "I'm happy that Technology Review correctly
recognized me as the true inventor of the technology," says Pompei.

Although I have not read it any detail, there is a Wikipedia article on
Parametric Loudspeakers.

It should not be surprising that high intensity ultrasound can generate
audible difference frequencies. Unfortunately, the nonlinear mathematics
required to describe a nonlinear process is complicated and non-intuitive.
While at first blush this complexity is a deterrent to working in the field,
it leaves much opportunity for invention and novelty.

Bill

 

[angelo Campanella]

I'd like to see this paper, anyone now how to locate it?
Dr. Joseph Pompei wins Technology Review's Award
for Audio Spotlight Directional Sound Technology

Sorry; we need a journal reference.

But I recognize it as "parametric sonar". It took me a while to resolve
what is being talked about since authors use different terminologies for
the same facts.

Two ultrasound beams from the same sender cross at some remote point in
space. Both beams are amplitude modulated with the same audio signal.
The ultrasound ampitude of the combined beam is locally doubled such
that nonlinear presssure vibrations occur at the modulated audio rate,
whereby audible sound emerges in the coss beam zone. That audio is a
traveling wave, and the wave propagation direction is the same as the
ultrasound beam. So in effect, a wave of audble sound has been generated
with very specific directionality; the same as that of the ultrasound
beams that formed the audio.

A lot of seculation and half-truths have emerged since the invention of
parametric sonar.

The human imagination provides wonderful entertainment...as is evident
in the following words:

The Audio Spotlight system uses nonlinearly propagating ultrasound to
create highly directional beams of sound in mid-air, which can be "shone"
and "directed" much like light. Dr. Pompei was the first in the world to
develop the mathematics and advanced engineering that allowed sound to be
created literally from thin air with sound quality and reliability rivaling
traditional loudspeakers. He presented his first paper and demonstration in
1998 to the Audio Engineering Society, and was met with a standing ovation
from the world's top audio professionals. Once the audio industry was shown
that such a system could actually work - and once Pompei published a paper
showing exactly how, several other groups have done their best to copy the
device, but none have succeeded. "I'm happy that Technology Review correctly
recognized me as the true inventor of the technology," says Pompei.

and they all lived happily after.

Ang. C.

 

[mike]

Sorry; we need a journal reference.

But I recognize it as "parametric sonar". It took me a while to resolve
what is being talked about since authors use different terminologies for
the same facts.

Two ultrasound beams from the same sender cross at some remote point in
space. Both beams are amplitude modulated with the same audio signal. The
ultrasound ampitude of the combined beam is locally doubled such that
nonlinear presssure vibrations occur at the modulated audio rate, whereby
audible sound emerges in the coss beam zone. That audio is a traveling
wave, and the wave propagation direction is the same as the ultrasound
beam. So in effect, a wave of audble sound has been generated with very
specific directionality; the same as that of the ultrasound beams that
formed the audio.

A lot of seculation and half-truths have emerged since the invention of
parametric sonar.

The human imagination provides wonderful entertainment...as is evident in
the following words:


and they all lived happily after.

Ang. C.

Hi Ang,

I note a bit of sarcasm in your response .
But there does seem to be real end users of the product.
See http://holosonics.com/press.html for some >advertised< users.
The short article in Scientific American (seemed) as if it only had one
driver,
anyone differ with that?
Mike

 

[angelo Campanella]

I note a bit of sarcasm in your response . why not..
But there does seem to be real end users of the product.
See http://holosonics.com/press.html for some >advertised< users.
The short article in Scientific American (seemed) as if it only had one
driver, anyone differ with that?

This particular non-linearity, aka cross modulation, is a progressive
effect, with the greater nonlinearity occurring at the greater distance
before diminished amplitude reverts to linear propagation, before
vanishing.

The original concept, ancient history now, used crossed or crossing
beams at first, if for no other reason than simplicity and the
availability of powerful transducers, I think.

This is now out of research and into the production engineering and the
market development phases.

Ang. C.

 

[Michael A. Terrell]

So those people who complain about the voices in their head that are
beamed by the government -- they're not kooks after all?

This would explain why the tinfoil hats don't seem to help much.

They can't afford good sound deadening foam to line their foil
beanies.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Rich Grise]

I'd like to see this paper, anyone now how to locate it?

Dr. Joseph Pompei wins Technology Review's Award for Audio Spotlight
Directional Sound Technology

Oh, hell - I thought you were talking about a piece of paper which, when
you apply a signal, emits sound. )-;

Thanks,
Rich

 

[amdx]

Oh, hell - I thought you were talking about a piece of paper which, when
you apply a signal, emits sound. )-;

Thanks,
Rich

Well Rich, I did think about rephrasing the subject line, but looks
like the idea got through.
Mike

 

[MooseFET]

So those people who complain about the voices in their head that are
beamed by the government -- they're not kooks after all?

This would explain why the tinfoil hats don't seem to help much.

It sure would make a good way to "Gas Light" someone.

 

[Fred Bloggs]

You will note _where_ it was invented ;-)

...Jim Thompson

Invented? His technical education was at RPI, a researcher at BOSE since
the age of 16, MIT multimedia lab last.

 

[Glen Walpert]

Invented? His technical education was at RPI, a researcher at BOSE since
the age of 16, MIT multimedia lab last.

In that case, he could not have invented the basic technology
(production of audible sound from the nonlinear mixing of two
ultrasonic sound sources), which was used to produce audible narration
and music apparently in mid air with no visible source in the General
Electric display at the 1964 worlds fair.

You can get the basic physics and math for this old technique in
'Fundamentals of Physical Acoustics' by Blackstock if you are
interested. It is only one of many interesting effects produced by
the inherently nonlinear characteristics of the propogation of finite
amplitude sound through a gas. Sound propogation through liquids is
also nonlinear, so the same thing could be done underwater.

Glen