Abstract
A directional source of audio sound created using a parametric array, sometimes called an audio spotlight, generates a sound beam that is much narrower than the sound beam generated by a conventional source. 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. Joseph Pompei’s Holosonic Research Labs invented the Audio Spotlight that is made of a sound processor, an amplifier and the transducer.
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The targeted or directed audio technology is going to a huge commercial market in entertainment and consumer electronics and technology developers are scrambling to tap in to the market. Audio spot light technology can do many miracles in various fields like Private messaging system, Home theatre audio system, Navy and military applications, museum displays, ventriloquist systems etc .Thus audio spotlighting helps us to control where sound comes from and where it goes!
I. Introduction
Audio spotlight is a very recent technology that creates focused beams of sound similar to light beams. By ‘shining sound to one location, specific listeners can be targeted with sound without other nearby hearing it, i.e. to focus sound into a highly directional beam.
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.
II. System Requirement
A. Hardware Requirement:
- A transducer(speaker).
- An amplifier.
- Coax cable.
III. Architecture
The ultrasound has wavelengths only a few millimeters long, which are much smaller than the source, and consequently travel in an extremely narrow beam.
Of course, the ultrasound, which contains frequencies far outside our range of hearing, is completely inaudible. But as the ultrasonic beam travels through the air, the inherent properties of the air cause the ultrasound to distort (change shape) in a predictable way. This distortion gives rise to frequency components in the audible band, which can be accurately predicted, and therefore precisely controlled. By generating the correct ultrasonic signal, we can create, within the air itself, essentially any sound desired.
Note that the source of sound is not the physical device you see, but the invisible beam of ultrasound, which can be many meters long. This new sound source, while invisible, is very large compared to the audio wavelengths it’s generating. So the resulting audio is now extremely directional, just like a beam of light.
Often incorrectly attributed to so-called “Tartini tones”, the technique of using high-frequency waves to generate low-frequency signals was in fact pioneered by physicists and mathematicians developing techniques for underwater sonar over forty years ago.
Through a combination of careful mathematical analysis and engineering insight, the Audio Spotlight sound system has become the very first, and still the only, truly directional audio system which generates low-distortion, high quality sound in a reliable, professional package.
IV. System Description
The Audio Spotlighting Device consists of a round shaped disc which consists of a transducer, an amplifier and coax cables.
Transducer is very discreet, at only 1/2” thick. The transducer comes in two standard sizes 18” round or 24” hexagonal. The cover of the audio spotlight is produced using sublimation printable lycra , this lycra cover can be printed to look like anything that we can take a digital picture of, making integration into an existing display or trade show environment even easier. this lycra cover can be produced with an elastic edge so that it is easily interchangeable. The transducer emits an ultrasound beam.
The transducers are driven by small ultrasound amplifiers. The amplifier receives the input signal from a standard audio source such as a computer, CD player or DVD player. The amplifier can currently push the sound signal through the cable 110′ long. The amplifier runs on standard 110v or 220v power and is very easily adaptable to European or Asian version of electrical power.
Coax cables are used to connect amplifiers to transducers.
V. Types
A. Direct Audio
B. Projected Audio
Directed audio can direct sound at a specific target, creating a contained area of listening space which is called “Direct audio”.
Protected audio can bounce can bounce of a sound object, creating an audio image. This audio image gives the illusion of a loudspeaker, which the listener perceives as the source of sound, which is called “projected audio”.
VI. Advantages
1. We can here sounds like music, speeches etc even disturbing others.
2. Army is using this technology which can be very advantageous to security.
3. Creates highly focused beam of sound.
4. Portable.
VII. Disadvantages
- It’s highly costly.
- It can be misused by enemies.
- Both speaker and amplifier are separate.
- Maintenance is high.
VII. Future Scope
Audio Spotlighting really “put sound where you want it” and will be “A REAL BOON TO THE FUTURE.”
VIII. Conclusion
It can be concluded that sound can be forced to make travel in one direction by using the technology audio spotlighting. We can here sounds like music, speeches even disturbing others.
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