silent sound - exclusive dealer of audio spotlight in south africa

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Technology

A new technology has been developed that can project a beam of sound so narrow that only one person can hear it.

"Directed" audio sounds like it's coming from right in front of you even when transmitted from up to 200 meters away.

Joseph Pompei, a PhD student at the MIT Media Lab, decided to develop it while working at audio company Bose, which he joined at 16

as its youngest-ever engineer.

The Audio Spotlight transmitters generate a column of sound between three and five degrees wider than the transmitter. It converts

ordinary audio into high-frequency ultrasonic signals that are outside the range of normal hearing. As these sound waves push out from

the source, they interact with air pressure to create audible sounds.

Silent Sound - Exclusive Dealer of Audio Spotlight in South Africa http://www.silentsound.co.za/technology.htm

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High-frequency signals are easier to focus, and control like a flashlight, than sounds that are within the human range of hearing, which

disperse in all directions. Ultrasonic signals decay more slowly than lower-frequency waves so they are easier to send farther.

The Audio Spotlight emits sounds in the 60-kilohertz range, which is well above the 20-KHz limit of human hearing.

Directivity Demonstrations

These simulations serve to demonstrate the following:

The directivity of all traditional loudspeaker devices is fundamentally limited by nothing morethan the size of the source compared to the wavelengths it generates.1.

No amount of phasing, shading, focusing, or any other method can overcome this fundamental

limit; in fact, any of these methods will always reduce directivity.

2.

It is impossible for any loudspeaker to approach the directivity of the Audio Spotlight.3.

Fixed Source Size, Varying Wavelength


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This simulation is of a fixed source size (0.4m/16"), with varying wavelength. From the statements above, we expect to see an omnidirectional

response for a large wavelength relative to source, and higher directivity as wavelength decreases.

Technical advice and consulting for Audio Spotlight!

Audio Spotlight - The Solution to one of life's many challenges

Did you ever need to put sound into just one small area of an exhibit or display? Ever struggle to make an environment moreeffective, engaging and quieter by eliminating overlapping sounds? Enter the Audio Spotlight!

Current / Previous SolutionsThe Audio Spotlight is a relatively new product developed at MIT that allows the user to beam sound into very small area of anexhibit or display. The beam from an Audio Spotlight is just 18 to 24 across and can be projected up to 200 meters. Untilapproximately 5 years ago, directional speakers such as sound dome products and steered arrays had been used to create

zones of sound. However, the sound projected from a sound dome or array is regular sound, shaped to remain in a smaller area.Once this standard sound leaves the confines of the dome, it immediately wants to spread out to fill up all of the spacesurrounding the dome. The sound from these more widely known products is about 60% directional at most.


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designers have struggled with for a long time.

Transducer (Speaker) PositioningFor the maximum volume (sound level) that trade show use demands, it is recommended that the Audio Spotlight speaker, more

accurately called a transducer, is mounted no more than 3 meters from the average listeners ears, or 5 meters in the air. Themounting hardware is constructed with a ball joint so that the Audio Spotlights are easily aimed wherever the sound is desired.

TransducerThe Audio Spotlight transducer is very discreet, at only 1.8cm thick. They come in two standard sizes 16" or 24.

AmplifierThe transducers are driven by a small ultrasound amplifier 5cm W x 4.5cm H x 7cm L. The amplifier receives the input signalfrom a standard audio source such as a computer, CD player or DVD. The amplifier can currently push the sound signal througha cable 30 meters long without any in-line signal amplification. Developments are currently being tested which will extend thatdistance a great deal. The amplifier runs on a 24 DC Volt Laptop type power supply.

Sound Track Production / Product Audio Performance

The Audio Spotlight does not currently reproduce bass below 350 Hz well. As a result, the audio track is produced, equalizedand mixed to eliminate unused tones. To create a more dynamic acoustic environment, the low tones can be added back into thespace with a subwoofer. Of course the sounds from a subwoofer will not be directional, but luckily, bass heard by itself is verynon-descript and thus, non-obtrusive. We have found that subwoofers are a non-distracting way to add the low tones back intothe space without unnecessarily increasing the sound level or potential for audio related distraction.

Silent Sound can produce the soundtracks for the Audio Spotlight at reasonable rates or supply outboard equalizers andcompressors depending on the program material or application.

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Holosonic and Audio Spotlight are trademarks of Holosonic Research Labs, Inc.

Copyright 2011 | Silent Sound | All rights reserved.

Silent Sound Exclusive Dealer of Audio Spotlight in South Africa http://www.silentsound.co.za/technology.htm

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silent sound - exclusive dealer of audio spotlight in south africa

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