A
SEMINAR REPORT
ON
HYPERSONIC SYSTEMS
Bachelor of Technology
In
Electronics & Communication
Engineering
Submitted to: Submitted by:
Dr. A. K. Gautam Amit Sati
Associate Professor Roll No-04
EEED, GBPEC ECE, IV Year
Pauri, Garhwal GBPEC, Pauri, Garhwal
PREFACE
This seminar is based on one of the latest trends in electronics, ‘HYPERSONIC
SYSTEMS’. It is a very recent technology that creates focused beams of sound similar to light
beams coming out of a flashlight. By ‘shining’ sound to one location, specific listeners can be
targeted with sound without others nearby hearing it. It uses a combination of non-linear
acoustics and some fancy mathematics. But it is real and is fine to knock the socks of any
conventional loud speaker. This acoustic device comprises a speaker that fires inaudible
ultrasound pulses with very small wavelength which act in a manner very similar to that of a
narrow column. The ultra sound beam acts as an airborne speaker and as the beam moves
through the air gradual distortion takes place in a predictable way due to the property of non-
linearity of air. This gives rise to audible components that can be accurately predicted and
precisely controlled. Joseph Pompei’s Holosonic Research Labs invented the Audio Spotlight
that is made of a sound processor, an amplifier and the transducer. The American Technology
Corporation developed the Hyper Sonic Sound-based Directed Audio Sound System. Both use
ultrasound based solutions to beam sound into a focused beam.
ACKNOWLEDGEMENT
I would like to thank Dr. Y Singh, Professor, HOD ECE Department for providing us this
valuable opportunity of presenting the seminar on latest trends in electronics and communication
which has not only enhanced my knowledge about the subject but also increased my confidence
level.
I would like to convey my special thanks to Dr. A.K Gautam, Associate Professor, EEE
Department for his valuable guidance and motivation. I express my sincere gratitude to Mr.
Manoj Kumar and Mr. Balraj for their co-operation.
I would also like to extend my cordial gratitude and regard to all my friends and
colleagues for their constant help and support. I am sincerely thankful to everyone who has given
me a part of his or her precious time for this seminar.
CONTENTS
1. INTRODUCTION
2. TECHNICAL OVERVIEW
2.1 The working
2.2 HSS systems
2.3 Non linearity property of air
3. ARCHITECTURE
3.1 Components of the system
4. BASIC BENEFITS
5. APPLICATIONS
6. CONCLUSION
7. REFERENCES
1. INTRODUCTION
Hyper Sonic Sound Systems (HSS) is a pioneering sound-generation technology that
broadcasts your message directly to your intended audience. In contrast to conventional
loudspeakers, HSS technology uses a directional ultrasonic column to produce sound exactly
where you want it. Sound does not spread to the sides or rear of an HSS unit, eliminating the
problem of uncomfortable and unwanted noise pollution produced by conventional speakers.
Sound is directed only where it is intended to go. Visualize two people standing four feet
apart at an art exhibit. One patron listens to a biography of a sculpture artist, while the other
contemplates a painting in complete silence! HSS is like handing someone a set of head
phones. By focusing sound in a tight column, HSS allows you to restrict sound to a specific
area without imposing on nearby speaker focused on the area in front of only directory users
to hear the corresponding audio.
Hypersonic Sound (HSS) is the term used to describe the process by which audible
sound waves can be produced using ultrasonic sound waves that are free from non-linearity.
The first attempts at hypersonic sound were made in the 1960’s using underwater sonar. In
the 1970’s it was proven that mathematically HSS could be produced in air, but by the
1980’s the technology was abandoned because of problems with distortion. In the late 1990’s
HSS was again researched because of advances in sound production technology and in 1998
the first working, commercial prototypes were made under the name “Audio Spotlight”.
The advantage of using ultrasonic sound is that sound transmissions can be focused into a
narrow, far-reaching beam that resists diffusion and attenuation; therefore, the beam can be
transmitted over greater distances with pinpoint accuracy. Additionally, this sound beam can
be targeted to only a single object or person, leaving the surrounding environment free of
noise pollution. Already, this technology is being put to use in the advertising and automobile
industries, and the United States military.
First, it is important to understand what a sound wave is. A sound wave is a series of
alternating high (condensation) and low (rarefaction) pressures created by some object
disturbing the environment through which the sound wave is traveling. This pressure wave,
then, is received by the eardrum which converts it through the inner ear into an electric signal
which the brain can process. The key thing to recognize in the case of hypersonic sound is
that each of these small pressure changes is a different micro-environment; the small portions
which are low-pressure have different densities (atmospheric density is related to pressure)
than those that are high-pressure. This is extremely important to note when dealing with the
transmission of a sound wave across distances.
Next, it is important to understand the terms diffusion and attenuation, which describe the
behavior of a sound wave over time. Diffusion is the process by which a sound wave expands
outward, and attenuation is the process by which a sound’s intensity diminishes. These two
characteristics of a sound wave are very interrelated; as a sound wave expands and increases
its area occupied, its intensity (which is inversely proportional to area occupied) decreases.
Additionally, a sound wave’s absorption into the surrounding environment as well as its
reflection off of objects and particles in the environment decreases its intensity and thus
contributes significantly to its attenuation.
Next, it is important to understand what it means to be non-linear and how or why a
sound wave is non-linear. Non-linearity simply means that as the wave advances through the
environment and time elapses, the conditions of the environment in which the wave exists do
not remain constant. Explaining how or why a sound wave is non-linear is a little more
complicated and requires the piecing-together of some facts which have already been noted.
Because a wave’s frequency depends on the speed of sound, and the speed of sound depends
on the density of the environment through which the wave is traveling, and the density of a
fluid (fluids are gasses and liquids) environment depends on the pressure—which is
fluctuating due to the nature of the wave—of the fluid, a wave’s frequency depends greatly,
although transitively, on the pressure of the fluid. As a wave moves through various
pressures, its frequency and speed change. Because the wave’s speed changes, the rate of
diffusion changes as a result of its rate of expansion changing. Because of both the rate of
diffusion changing, and because of the amount of particles to reflect off of (because of the
compression and rarefaction, where lower densities have fewer particles and vice-versa)
changing, the rate of attenuation changes. All of these factors are even further affected as the
sound wave travels outwards because of the diminished intensity and conversely the
diminished compression, rarefaction, attenuation, and diffusion. Thus, a sound wave is non-
linear both in small segments (from one micro-environment to the next) and as an entire
segment (as its intensity diminishes from the source at point A to the target at point B).
2. TECHNICAL OVERVIEW
The HSS Directional Audio System can operate in Direct Mode, a clear line of approach
from the HSS unit to the target listener, and in Virtual Mode, projecting sound onto a sign,
display or other object creating a Virtual Speaker.
Direct Mode assumes that the listener will be in a direct path in front of the HSS device.
He or she will hear the audible sound as the sound column passes by their head. The sound will
continue to travel past them until it either strikes a surface or is absorbed by the air (over a long
distance). A number of things can happen when a sound wave strikes a surface depending on the
surface itself. If the surface is flat and hard (e.g. a mirror or plaster board), the sound will reflect
from the surface. Some energy will be lost, but some of the sound will be reflected back into the
environment. The angle at which the sound strikes the surface will equal the angle at which it
will reflect (assuming a perfect reflector). Of course, there is no perfect reflector so some amount
of the sound will scatter back into the entire area, while the loudest portion will follow the
refection path. If the surface is absorptive at the proper frequencies, the surface will contain the
sound within the surface and little sound will be directed back into the environment. The last
alternative is to make the surface diffusive. If you diffuse the reflection you essentially reflect it
back into the room in all directions. Therefore, no single reflection is louder than all the rest.
One of the great benefits of HSS is the fact that we can now predict where the sound will
strike a surface (first reflection) and treat that surface accordingly. Since traditional loudspeakers
emit sound in all directions, the sound always sounds like it is coming the speaker device
because no matter where you are in the room, the first sound you hear is actually coming directly
at you from the speaker. Now, with HSS, we only have the one column of sound to deal with.
1) REFLECT IT: Angle the HSS device correctly so that the first reflection is directed
where you want it to go. For example, if you don’t want to hear the first reflection, direct it up
into the ceiling, or direct it into an absorptive surface someplace else in the room, etc. Also
remember that sound does dissipate over distance. Therefore, the farther you can make the
reflection travel, the lower it will be in volume when you hear it again. A good example would
be an overhead HSS unit directed down towards the floor with the first reflection going back up
into the ceiling. If the ceiling were 50 ft. away, the reflected sound would have to travel 50 ft. up
and 50 ft. back down before you would hear it again. It may be completely inaudible by that time
depending on how loud it was when it started, the composition of the ceiling, and ambient sound
level.
2) ABSORB IT: Make the surface struck by the first sound reflection highly absorptive.
The better the absorber, the lower the reflected energy. Carpet, for example, is a very poor
absorber. It will absorb some of the highest sound frequencies, but will reflect the remainder.
Some office wall panels are somewhat better, but still they will reflect the majority of the energy.
A local acoustical technician can provide you with the most appropriate absorption
material for the individual installation.
3) DIFFUSE IT: Make the surface multi-layered and multi- dimensional. The more
irregular the surface, the better the diffusion.
HSS can transform signs, placards, and surfaces into Virtual Speakers. Virtual Mode
applications allow units to be placed without cabinet or hardware at the desired sound location.
By projecting sound with an HSS unit, a simple display sign can act as a speaker without wiring
or changing the sign’s appearance. You can project HSS sound to specific end caps or aisle
displays or send sound across the room, without uncomfortable and unwanted volume from
loudspeakers. HSS can turn a wall into an information sound center by adding sound to coupon
panels and directional signage to increase interest.
Imagine:
Introducing a new product and telling customers how to use it at the store display with the
audio message heard only by those standing in front of the display.
Museums, amusement parks, theme parks, or zoos with display-point audio that provides
directions or a narrative about displays or exhibits without the need for conventional headphones.
Providing a section for the hearing impaired at public assemblies, in churches, and in
schools where sound can be enhanced without disruption to other attendees.
Computer operators in an office of cubicles with HSS units placed overhead directing
sound at each individual with no disturbance to coworkers.
Display booths at trade show that direct sound only to those in or in front of the booth,
keeping noise levels to a minimum.
Projecting the audio from an audio/video conference, in four different languages from a
single central device, reaching the intended parties without headphones.
Safety warnings that penetrate general noise in heavy equipment staging areas, rental sites, or
repair yards so that it can be heard by those in risk areas.
Signaling, alerting, and informing specific c individuals in a grocery aisle, waiting room,
or lobby.
Use of the HSS unit to add audio to an ATM with only the customers actually at the
ATM able to hear the message.
All this is now possible with the new hypersonic sound systems.
The unique technical characteristics of HSS offer superior control of sound. HSS creates
new opportunities for designers to implement and use sound as never before. Architects now
have the ability to integrate sound into designs with exciting control of placement. With the HSS
Virtual Mode capability, sound can be added without having to place a loudspeaker where the
sound is needed. Audio engineers will find that HSS is applicable in any situation where it is
desirable to limit the ability to hear sound to a defined space. Since HSS delivers sound
precisely, less volume is necessary to project sound where it is needed; HSS does not inflict
excessive sound pressure at one point to carry the sound to the desired place. HSS can create
virtual loudspeakers, so that sound appears to be coming from points where it would be
impractical or impossible to place a loudspeaker. Hypersonic Sound is a paradigm shift in sound
production based on solid principles of physics.
The human ear is sensitive to frequencies from 20 Hz to 20,000 Hz (the "audio" range),
and can detect the vibration amplitudes that are comparable in size to a hydrogen atom. If the
range of human hearing is expressed as a percentage of shifts from the lowest audible frequency
to the highest, it spans a range of 100,000%. No single loudspeaker element can operate
efficiently or uniformly over this range of frequencies. In order to deal with this speaker
manufacturers carve the audio spectrum into smaller sections. This requires multiple transducers
and crossovers to create a 'higher fidelity' system with current technology. Using a technique of
multiplying audible frequencies upwards and superimposing them on a "carrier" of say, 200,000
cycles the required frequency shift for a transducer would be only 10%. Building a transducer
that only needs to produce waves uniformly over only a 10% frequency range. For example, if a
loudspeaker only needed to operate from 1000 to 1100 Hz (10%), an almost perfect transducer
could be designed an almost perfect transducer could be designed.
2.1 The working
Hyper Sonic Sound technology creates audible sound from the interaction of
two high-frequency signals that are themselves inaudible. A reference signal is held constant at
200 kHz and a variable signal which ranges from 200.020 kHz to 220 kHz are the signals used.
The reference signal combines with variable signal to produce audible signal in the air whose
frequency is equal to the difference between the variable and reference frequencies. As an
example to produce a sound of 263 Hz, the variable signal is made to 200.263 kHz. These
ultrasonic frequencies are inaudible by themselves. However, the interaction of the air and
ultrasonic frequencies creates audible sounds that can be heard along a column. This audible
acoustical sound wave is caused when the air down-converts the ultrasonic frequencies to the
lower frequency spectrum that humans can hear. The basic operating principal of HSS uses a
property of air known as "non-linearity". A normal sound wave (like someone talking) is a small
pressure wave that travels through the air. As the pressure goes up and down, the "nonlinear"
nature of the air itself causes the sound waves to be changed slightly. If you change the sound
waves, new sounds (frequencies) are formed within the wave. Therefore, if we know how the air
affects the sound waves, we can predict exactly what new frequencies (sounds) will be added
into the sufficient volume to cause the air to create these new frequencies.
Since we cannot hear the ultrasonic sound, we only hear the new sounds that are formed
by the non-linear action of the air. Since the audible sound is produced inside the column of
ultrasonic frequencies (which is highly directional), an important by-product of this is that the
audible sound can be tightly focused in any direction within the listening environment. This
provides outstanding edibility in placing the sound exactly where you want it and substantially
eliminating sound in all other areas. The directionality of the HSS system is unsurpassed, with
the added benefit of long projection distances and retention of intelligibility. Getting sound right
where it is wanted eliminates having to use high sound pressure levels to get sound to “carry” to
distant points.
2.2 HSS systems
A Hyper Sonic Sound system consists of an audio program source such as a CD player or
microphone, an HSS signal processor, and an ultrasonic emitter or transducer that is powered by
an ultrasonic amplifier. The music or voice from the audio source is sent to an electronic signal
processor circuit where equalization, dynamic range control, distortion control, and precise
modulation are performed to produce a composite ultrasonic wave. The wave form is converted
to a highly complex ultrasonic signal by the signal processor before being amplified. The patent
pending ModAmp™ technology is used to produce the compact and lightweight
Modulation/Amplifier portions of HSS. This amplified ultrasonic signal is sent to the emitter and
emitted into the air to produce a column of ultrasonic sound that is subsequently converted to
highly directional audible sound within the air column. Since the ultrasonic energy is highly
directional, it forms a virtual column of sound directly in front of the emitter, much like the light
from a flashlight. All along that column of ultrasonic sound, the air is creating new sounds (the
sound that we originally converted to an ultrasonic wave). Since the sound that we hear is
created right in the column of ultrasonic energy, it does not spread in all directions like the sound
from a conventional loudspeaker; instead it stays locked tightly inside the column of ultrasonic
energy. In order to hear the sound, your ears must be in line with the column of ultrasound, or,
you can hear the sound after it reflects off a hard surface. For example, if you point the ultrasonic
emitter toward a wall, you will only hear the audible sound after it has reflected off the wall. This
is similar to shining a flashlight at a wall in a dark room. You do not see the light from the
flashlight; you only see the spot of light on the wall. HSS works the same way, except instead of
seeing the spot of light on the wall; you hear the "spot" of sound reflected from the wall. For
stereo, a separate ultrasonic emitter is required for each channel of audio, one for the left channel
and one for the right channel.
2.3 Non linearity property of air
When two sound sources are positioned relatively closely together and are of a sufficiently high
intensity, two new tones appear: a tone lower than either of the two original ones and a tone
which is higher than the original two. There are now four tones where before there were only
two. It can be demonstrated mathematically that the two new tones correspond to the sum and the
difference of the two original ones, which we refer to as combination tones.
For example, if you were to emit 200,000 Hz and 201,000 Hz into the air, with sufficient
energy to produce a sum and difference tone, you would produce the sum - 401,000 Hz - and the
difference - 1,000 Hz, which is in the range of human hearing.
The HSS concept originates from this theory of combination tones, a phenomenon known
in music for the past 200 years as "Tartan tones." It was long believed that Tartan Tones were a
form of beats because their frequency equals the calculated beat frequency. However, it was
Hermann von Helmholtz (1821-1894) who completely re-ordered the thinking on these tones. By
reporting that he could also hear summation tones (whose frequency was the sum rather than the
difference of the two fundamental tones) Helmholtz demonstrated that the phenomenon had to
result from a non-linearity. Could a method be found today to utilize this non-linearity of air
molecules in a manner similar to the non-linearity of an electronic mixer circuit?
In theory, the principle appears quite simple. Yet, until now, no one has succeeded in
making it work. Nobody has been successful in producing useful levels of sound output in this
difference frequency range. ATC ,the makers of the Hyper Sound Systems thinks that better
audio can be created with a process that they call acoustic heterodyning - mixing signals
together to create new ones - in a process analogous to what virtually every radio receiver uses
today.
Mix two signals in a nonlinear medium and you'll end up with four - two at the original
frequencies, a third at a new frequency that is equal to the sum of the two signals (the sum
frequency) and a fourth at a frequency equal to the difference of the original two signals (the
difference frequency).
Radio receivers use heterodyning to make the signals more manageable - the signal is
converted to a lower frequency (called the intermediate frequency, or IF) by being mixed with a
local oscillator. This allows greater and more consistent amplification of the desired signal
because the amplification circuitry can be optimized for only the IF instead of a wide range of
frequencies.
What makes acoustic heterodyning possible is that air molecules behave nonlinearly - when
sound has a high enough amplitude, the restoring force on the air molecule varies as the square
of its displacement from equilibrium - so that mixing can occur. Take an ultrasonic transducer,
feed it the right signals, they'll mix, and you'll hear the difference frequency. (The original
signals and the sum frequency are outside the range of hearing.)
Acoustic heterodyning can be created by a single transducer or by a pair of transducers. A
single transducer would be fed a signal at a "carrier frequency" and a second signal that would
provide the desired (audible) difference frequencies when mixed with the carrier. If a pair of
transducers was used, one would operate at the carrier frequency and the second at a frequency
required producing the desired output. If the carrier frequency of the transducer were 200 kHz,
an upward swing of 20 kHz - or just 10 percent - would cover the entire audio range. In theory,
this should result in a response that is virtually flat across the audio range - something that no
speaker could hope to match. Other benefits include extremely high efficiency when compared
with traditional speakers, and - since the sound seems to come from a single point in space -
perfect phase coherency.
The audio created by acoustic heterodyning is extremely directional, due to the high
frequency of the ultrasonic carrier. In a demonstration of the technology, we could "shine" the
transducer at a wall, and the sound would seem to emanate from there just as if we had hit it with
a flashlight beam.
This directionality could be used in a movie theater by generating ultrasounds with separate
transducers and swiveling the transducers to change the point where the ultrasound beams would
meet, making sound hover or travel over the heads of viewers. Giving directors the ability to put
sound exactly where they want it adds a whole new dimension to surround sound. Although
acoustic heterodyning has extraordinary promise, don't throw your speakers on the trash heap
just yet. In our demonstration, the transducer was only able to create sound equivalent to a small
AM transistor radio. It completely lacked a bottom end.
ATC is now working with Carver Corp. to improve the technology's performance to make
this audio reproduction revolution a reality. Expect to see some commercial products within a
few years.
It's difficult for any conventional speaker to reproduce the entire spectrum of human
hearing, which extends from deep bass notes at 20 hertz (cycles per sound) to shrill 20,000-hz
tones. Speaker materials that can make rich bass sounds can't accurately handle high notes.
Consequently, speaker boxes typically house two or more speakers, each specializing in narrow
tonal ranges. Now, all these complexities go out the window. Norris' little Hyper Sonic speakers
aren't troubled by the breadth of human hearing because they operate in a different realm--the
ultrasonic. One of the two ultrasonic signals that produce audible sound as a byproduct is a
constant 200,000-hz frequency. It's mixed with a second signal that varies from 200,020 Hz to
220,000 Hz. Subtract one from the other, and the resulting tones run the audible gamut.
3. ARCHITECTURE
Hypersonic sound uses a property of air known as ‘nonlinearity’. A normal sound wave is
a small pressure wave that travels through the air. As the pressure goes up and down, the
‘nonlinear’ nature of the air itself slightly changes the sound wave. If there is change in a sound
wave, new sounds are formed within the wave. Therefore if we know how the air affects the
sound waves, we can predict exactly what new frequencies (sounds) will be added into the sound
wave by the air itself. An ultrasonic sound wave (beyond the range of human hearing) can be
sent into the air with sufficient volume to cause the air to create these new frequencies. Since we
cannot hear the ultrasonic sound, we only hear the new sounds that are formed by the nonlinear
action of the air.
Hypersonic sound technology precisely provides linear frequency response with virtually
no distortion associated with conventional speakers. Physical size no longer defines fidelity. The
faithful reproduction of sound is freed from bulky enclosures. There are no woofers, tweeters or
crossovers.
An important byproduct of this technique is that sound may be projected to just about any
desired point in the listening environment. This provides outstanding flexibility, while allowing
for an unprecedented manipulation of the sound’s source point.
Hypersonic technology is analogous to the beam of light from a flashlight. If you stand to
the side or behind the light, you can ‘see’ the light only when it strikes a surface. This technology
is similar in that you can direct the ultrasonic emitter towards a hard surface, a wall for instance,
and the listener perceives the sound as coming from the spot of the wall.
3.1 Components of the system
Power supply: Like all electronics, the hypersonic sound system works off dc voltage. A
universal switch mode power supply is standardized at 48V for the ultrasonic power amplifier. In
addition, low voltage is used for the microcontroller unit and other process management.
Audio signal processing: The audio signal is sent to an electronic signal processor circuit where
equalization, dynamic range control and precise modulation are performed to produce a
composite ultrasonic waveform. This amplified ultrasonic signal is sent to the emitter, which
produces a column of ultrasonic sound that is subsequently converted into highly directional
audible sound within the air column.
Since ultrasound is highly directional, the audio sound placement is precise. At the heart
of the system is a high precision oscillator in the ultrasonic region with a variable frequency
ranging from 40 to 50 kHz.
Dynamic double side-band (DSB) modulator: In order to convert the source program material
into ultrasonic signals, a modulation scheme is required. In addition, error correction is needed to
reduce distortion without loss of efficiency. The goal, of course, is to produce audio in the most
efficient manner while maintaining acceptably low distortion levels.
We know that for a DSB system, the modulation index can be reduced to decrease
distortion, but this comes at the cost of reduced conversion efficiency. A square-rooted envelope
reference with zero bandwidth distortion, the basis of the proprietary parametric processor,
handles the situation effectively.
Ultrasonic modulation amplifier: High efficiency ultrasonic power amplifier amplifies the
carrier frequency with correlation, responds to reactive power regeneration and matches the
impedance of the integrated transducers.
Microcontroller: A dedicated microcontroller circuit takes care of the functional management
of the system. In the future version, it is expected that the whole process like functional
management of the system, signal processing, double side-band modulation and even switch
mode power supply would be effectively taken care of by a single embedded IC.
Transducer technology: The most active piezo film is polyvinylidene difluoride. This film is
commonly used in many industrial and chemical applications.
In order to be useful for ultrasonic transduction, the raw film must be polarized or
activated. This is done by one of the two methods. One method yields a ‘uniaxial’ film that
changes length along one axis when an electric field is applied through it. The other method
yields a ‘biaxial’ film that shrinks/expands along two axes. Finally, the film needs to have a
conductive electrode material applied to both sides in order to achieve a uniform electric field
through it.
Piezoelectric films operate as transducers through the expansion and contraction of ‘X’ or
‘Y’ axes of the film surface. For use as a hypersonic sound emitter, the film is to be curved or
distended. The curving results in expansion and contraction in the ‘Z’ axis, generating acoustic
output.
The music or voice from the audio source is converted into a highly complex ultrasonic
signal by the signal processor before being amplified and emitted into the air by the transducer.
Since the ultrasonic energy is highly directional, it forms a virtual column of sound directly in
front of the emitter, much like the light from a flashlight.
Specifications of a typical HSS
SOUND BEAM PROCESSOR/AMPLIFIER
1. Worldwide power input standard
2. Standard chassis 6.76”/171mm (w) x 2.26”/57mm (h)x 11”/280mm (d), optional rack
mount kit
3. Audio input: balanced XLR, 1/4” and RCA (with BTW adapter) Custom
configurations available e.g. Multichannel
AUDIO SPOTLIGHT TRANSDUCER
1. 17.5”/445mm diameter, 1/2”/12.7mm thick, 4lbs/1.82kg
2. Wall, overhead or flush mounting
3. Black cloth covers standard, other colours available
4. Audio output: 100dB max
5. ~1% THD typical @ 1 kHz
6. Usable range: 20m
7. Audibility to 200m
8. Optional integrated laser aimer 13”/ 330.2mm and 24”/ 609.6mm diameter also
available
9. Fully CE compliant
10. Fully real time sound reproduction - no processing lag
4.BASIC BENEFITS
1. Small Size
Not only has the conventional speaker's crossover network and enclosure been
eliminated, but HSS' ultra-small radiating ultrasonic emitter is so small and light-weight
that the inertial considerations ordinarily associated with traditional direct-radiation
speakers are virtually non-existent. (And so is just about everything else associated with
the conventional speaker: the voice coil and support structure normally used to attach the
moving cone in place.)
2. Point Source
The ability to produce the entire audible spectrum of frequencies from a single
point source has been the goal of transducer engineers for the past 50 years. The
improvement in phase response, time alignment, and frequency response becomes
obvious.
3. Performance
Preliminary testing of the ATC proof-of-concept prototype shows the HSS
technology should have the potential for the following performance specifications:
a. Dynamic range up 120 dB at all frequencies
b. No crossover networks
c. Precise phase and time alignment
d. Room interaction reduced up to 50 dB
e. Frequency response from below 10 Hz to 30 kHz
5. APPLICATIONS
The applications are many, from
targeted advertising to virtual rear-channel
speakers. The key is frequency: The
ultrasonic speakers create sound at more than
20,000 cycles per second, a rate high enough
to keep in a focused beam and beyond the
range of human hearing. As the waves disperse, properties of the air cause them to break into
three additional frequencies, one of which you can hear. This sonic frequency gets trapped within
the other three, so it stays within the ultrasonic cone to create directional audio. Step into the
beam and you hear the sound as if it were being generated inside your head. Reflect it off a
surface and it sounds like it originated there. At 30,000 cycles, the sound can travel 150 yards
without any distortion or loss of volume. Here's a look at a few of the first applications.
1. Virtual Home Theater
about 3.1-speaker Dolby Digital
sound? With Hypersonic, you can
eliminate the rear speakers in a 5.1
setup. Instead, you create virtual
speakers on the back wall.
2. Targeted Advertising
"Get $1 off your next purchase of
Wearies," you might hear at the
supermarket. Take a step to the right,
and a different voice hawks Crunch
Berries.
3. Sound Bullets
Jack the sound level up to 145
decibels, or 50 times the human
threshold of pain, and an offshoot of
hypersonic sound technology becomes
a non lethal weapon.
4. Moving movie voices.
For heightened realism, an array of directional speakers could follow actors as they walk across
the silver screen, the sound shifting subtly as they turn their heads.
5. Pointed Messages
"You're out too far," a lifeguard could yell into his hypersonic megaphone, disturbing none of the
bathing beauties nearby.
6. Discreet Speakerphone
With its adjustable reach, a hypersonic speakerphone wouldn't disturb your cube neighbors.
The following contains a brief list of other uses made possible by HSS:
• Museums - describe each exhibit to only the person standing in front of it
• Automobiles - HSS announcement device in the dash to “beam” alert signals directly to the
driver
• Audio/Video Conferencing - project the audio from a conference in four different languages,
from a single central device, without the need for headphones.
• Paging Systems - direct the announcement to the specific area of interest
• Retail Sales - provide targeted advertising directly at the point of purchase
• Drive Through Ordering – intelligible Communications directly with an automobile driver
without bothering the surrounding neighbors
Besides consumer electronics, the entertainment industry is expected to be fundamentally
influenced by this development. In a movie theater, sound can be made to emanate directly from
an actor's mouth on the screen. Special effects will no longer be limited to the capability of
loudspeakers positioned around the auditorium.
You might want to project concert sound throughout an audience instead of using huge
speaker stacks in front. A small table radio might project sound around an entire room. Why not
equip your back yard with tightly focused HSS emitters to project sound all around your yard for
that next pool party.
Until now, it has been difficult for a hearing aid--regardless of price--to reproduce the
entire audio spectrum. This no longer need be the case. With HSS, hearing aids may also shrink
further in size. Virtual reality, in large-scale applications, has been brought another step closer.
No longer is the quality of the sound related to the size or type of a speaker's enclosure.
Everywhere and anywhere a speaker is in use today--ships, aircraft, hospitals, automobiles--the
HSS technology can replace the bulkier, inefficient speakers, and provide far better results than
we have ever heard. Truly, this is a quantum leap, a paradigm shift.
6. CONCLUSION
As a conclusive remark, this paper discussed about the coming of the Hypersonic Speaker
Systems which are yet not implemented, but is a real promising innovation which may be applied
in our everyday life and will revolutionize the sound technology. This paper discussed about the
invention, the inventor, the motive behind the invention, etc. Also discussed about how
hypersonic sound is created and how the hypersonic system works, which method is used, etc.
What the advantages of hypersonic speakers are, over conventional systems. We also discussed
about their wide forms of applications.
7. REFERENCES
• http://www.atcsd.com
• http://www.usatoday.com
• http://www.acoustic.org
• http://www.m-media.com
• http://www.thinkdigit.com
• http://www.holosonics.com
• http://www.spie.org
• http://www.howstuffworks.com
• http://www.abcNEWS.com