• Specific listeners can be targeted with sound without others nearby hearing it.

• It makes use of non-linearity property of air.

• The ultrasound column acts as a airborne speaker and as the beam moves through the air gradual distortion takes place in a predictable way.this gives rise to audible components that can be accurately predicted and controlled.

• This low frequency signal is frequency modulated with  ultrasonic frequencies range with wave length of few millimeters.

• Since the wavelength is smaller the beam angle will be around 3 degree, as a result the sound beam will be a narrow one with a small dispersion.

1.  Power Supply.

2.  Frequency oscillator.

3.  Modulator.

4.  Audio signal processor.

5.  Microcontroller.

6.  Ultrasonic amplifier.

7.  Transducer.

• Far more directivity and isolation from conventional speakers.

• Orientation matters a lot.

• Uses Ultrasonic Wave technology in order to create extremely narrow beams of sound.

• Uses inherent non-linearity of air for demodulation

• The focused or directed sound travels much faster in a straight line than conventional loudspeakers.

• Dispersion can be controlled – very narrow or wider to cover more listening area.

• Can reduce or eliminate the feedback from microphones.

•Highly cost effective as the maintenance required is less as compared to conventional loud speakers and many more ....!

• In 1975, first publication demonstrated linear effects of air which became the basis of audio spotlighting.

• Over 2 decades companies have tried to develop this technology but till 1980's there were high level of distortions which almost lead to total abandonment of this technology but now it is developing in full pace.

• Museums:- Individual monuments or sight can have localised audio and people standing nearby wont be disturbed as they cant hear.

• Automobiles:- Everyone has different taste of music while travelling and a loudspeaker cant be used as an audio system here. But audio spotlight can be of great use as every individual can have own spotlight speakers and can hear music of their interest !!

• But the customers use them as the materials are naturally very weather- resistant.

• For increased protection people used plastic sheeting to prevent water from entering thus increasing its use in outdoor activities.

• But the maximum performance is attained at roughly (1-2)m from the listener.

• The audible distance is mostly dependent on ambient noise levels and physical objects in the beam path.

• There were lot of websites and book which gave me a good platform to expresss my views and knowledge about Audio spotlight

• www.theaudiospotlight.com

• https://en.wikipedia.org/wiki/Holosonics

• www.holosonics.com

Title:- Handbookfor Sound Engineers

Author:- Glan Ballou

Edition:- 5 (revised)

Publisher:- CRC Press

Year Of Publication:- 2015

ISBN:- 1135016658, 9781135016654

Sites :-

2. www.holosonics.com

3. www.theaudiospotlight.com

4. www.technologyreview.com/featuredstory/402725/the-sound-war/

1.Title :-  "The audio spotlight: An application of nonlinear interaction of sound waves to a new type of loudspeaker design".

2. Author :- Yoneyama, Masahide; Jun Ichiroh, Fujimoto

3. Edition :- 7(revised)

4. Publisher :- The Journal of the Acoustical Society of America

5. Year of publication :- 5 May 1983

*Websites

1. www.statusav.com/directional-audio/audio-spotlight/

2. www.boston.com/business/

3. www.theaudiospotlight.com

4. www.holosonics.com/

5. www.econtact.ca/14_4/copeland_spotlight.html

* Videos

1. https://www.youtube.com/watch?v=Dd0m0C3f158

* Commercial

* Advertising

* Personal Audio

* Train Signaling Device

* Uses ultrasonic energy

* Creates extremely narrow beam of sound that behaves like a beam of light

* Ultrasonic mode is used since it has small wavelength

* Low beam angle is required to focus

* Sharper directivity

* Uses non-linearity of air for demodulation

* Cost effective

*

Ans. The term audio spotlight was first coined in the year 1983 by the japanese researchers. The first device was created in the year 1998 and was known by the trademark name AUDIO SPOTLIGHT.

2. Since how long research is going on this field?

Ans. The research is going on this field since 1960.

3. Who developed the concept of audio spotlight?

Ans. F. Joseph Pompei of MIT developed the technology known as AUDIO SPOTLIGHT and made it commercially available in 2000 by his company Holosonics.

4. What are the target audience of this post?

Ans. The target audience of this post are undergraduate engineering and pure science students. Audio spotlight are of immense use in future is going to be a vast area for research.

The plan is to find out in what all areas and in what ways audio spotlight can be used and what all traditional technologies they can replace.

1. Modulation:- Process of changing any desirable property in the wave by transposing some other wave. Here, it is used in converting human voice frequency to ultrasonic frequency.

2. Oscillator:- It is an electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave. It is used  here in creating desired sound output signal.

3. Ultrasonic waves :- These are the waves with frequencies higher than the audible range of human ear. It is used in maintaining a small beam angle !

2. COMMERCIAL ADVERTISING :- In commercial applications, it can target sound to a single person without the peripheral sound and related noise of a loudspeaker.

3. PERSONAL AUDIO :- It can be used for personal audio, either to have sounds audible to only one person, or that which a group wants to listen to.

4. TRAIN SIGNALING DEVICE :- Directional audio train signaling may be accomplished through the use of an ultrasonic beam which will warn of the approach of a train while avoiding the nuisance of loud train signals on surrounding homes and businesses.^[5]

It can remove the need of guides and can provide correct information about the monuments present in the museum as local speakers can be assigned for each specific monument and information can only be given to people watching it

1. Direct Audio :- Audio Spotlight transmitter can be directed towards a specific target , creating a contained area of listening space.

2. Projected Audio:- Audio Spotlight Wave coming from the source can be bounced off a object or a wall which creates an audio image. This audio image gives the illusion of loudspeaker to listeners.

It is widely used to detect the exact position of the enemies. It is also used as a "brown noise" which is used as directed beam of sound that makes the target lose control of bowels. Thus it also helps to target missiles.

The audio spotlight uses ultrasonic energy to create extremely narrow beam of sound that behave like beam of light. Audio spotlighting exploits the property of non-linearity of air. When inaudible ultrasound pulses are fired into the air, it spontaneously converts the inaudible ultrasound into audible sound tones. like audible sound ultrasound waves, get distorted as they travel through air. The ultrasound waves are breaked into lower frequency, i.e. audible sound waves. so these ultrasound waves can travel along a narrow path, people to left or right of a target remain silence

2. D. Meyer. Computer Simulation of Loudspeaker Directivity, J. Audio Eng. Soc

3. Houghton Mifflin Company,2006 The American heritage Dictionary of English language,

4. J. Eargle, Loudspeaker Handbook, Chapman and Hall, New York

5. J. Proakis and D. Manolakis, Digital Signal Processing, Principles, Algorithms, and Applications

6. M. Yoneyama and J. Fujimoto. The audio spotlight: An application of nonlinear interaction of sound waves to a new type of loudspeaker design, J. Acoustical Society of America

7. P. Hong, IMTC, Georgia Institute of Technology

8. T. Chen, Guest Editor. The Past, Present, and Future of Audio Signal Processing, IEEE Signal Processing Magazine.

9. Universal physics.

10. W.F Dryvestegn & J. G