Audio spot lighting is a new technology that uses ultrasonic frequencies to create narrow beams of focused sound in a similar way that light can be focused into a beam. It exploits the non-linearity of air to generate audible sound from ultrasonic waves. An array of transducers emit ultrasonic signals that distort in a predictable way as they pass through air, generating a focused beam of audible sound that only those within the beam can hear without disturbing others nearby. This technology allows sound to be targeted to specific listeners without the dispersion of omnidirectional speakers. It has applications in areas like retail stores, museums, and public announcements.

1. AUDIO
SPOTLIGHTING

2. INTRODUCTION
• Audio spot lighting is a very recent technology that creates a
focussed beams of sound similar to light beams coming out of a
flash light.
• Specific listeners can be targeted with sound without others
nearby hearing it.
• It makes use of non-linearity property of air.

3. CONVENTIONAL SPEAKERS AUDIO SPOTLIGHTING

4. HOW IS THE SOUND FOCUSED INTO A
NARROW BEAM???
• Maintain a low beam angle that is dictated by wavelength.
• The smaller the wavelength,the less the beam angle,
the more focussed will be the sound.
• The audio spot light uses ultrasonic energy to create extremely
narrow beams of sound .
FOCUSED BEAM OF SOUND

5. • 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…..
DEMONSTRATION OF HOW
INVISIBLE ULTRASOUND WAVE
WORKS

6. RANGE OF HEARING

7. WORKING
• Ultra sonic frequencies :21 khz to 28 khz
• Wavelength :few millimeters
• Beam angle :3 degree
Narrow beam with small dispersion……
AUDIO SPOTLIGHTING EMITTER

9. DISPERSION OF SOUND BEAM

10. BLOCK DIAGRAM OF AN AUDIO SPOLIGHTING SYSTEM

11. TRANSDUCER: These
transducers are arranged in form of an array called parametric array in order to
propagate the ultrasonic signals from the emitter and thereby to exploit the nonlinearity
property of air.

12. MODES OF LISTENING:

13. ADVANTAGES
•Can focus sound only at the place you want.
•Ultrasonic emitter devices are thin and flat .
•The directed sound travels much faster .
•Dispersion can be controlled.
•Highly cost effective and longer life span.
•Requires same power as required for regular speakers.
•There is no lag in reproducing the sound…..

14. APPLICATIONS:
AUTOMOBILES • SAFETY OFFICIALS MUSEUMS
• MILITARY APPS
• AUDIO/VIDEO
CONFERENCING
• SOUND BULLETS
PUBLIC ANNOUNCEMENT RETAIL SALES

15. CONCLUSION
Even the best loudspeakers are subject to distortion and their omni direction
sound is annoying to the people in the vicinity who do not wish to.the audio
spotlight will force people to rethink their relationship with sound.audio
spotlighting really
“PUT SOUND WHERE YOU WANT IT”

16. REFERENCE
1) F. Joseph Pompei. The use of airborne ultrasonics for generating audible sound beams.
Journal of the Audio Engineering Society, P. J. Westervelt. Parametric acoustic array.
Journal of the Acoustical Society of America.
2)Thomas D. Kite, John T. Post, and Mark F. Hamilton. Parametric array in air:
Distortion reduction by preprocessing. Journal of the Acoustical Society of America.
3) Jacqueline Naze Tjotta and Sigve Tjotta. Nonlinear interaction of two
collinear,spherically spreading sound beams.
4) www.silentsound.co.za – Silent sound.
5)www.wikipedia.org - Sound from Ultrasound.
6) www.howstuffworks.com
7)www.techalone.com-audio spotlighting.
8)www.holosonics.com
9)Electronics for you-vol.40 January 2008.

18. Queries???