Announcing the Emergence of Active Noise Control 'Anti-Noise'
in Silencing Hardware Noise: CeBIT 2006, 9-15 March, Hannover, Germany
Rise in Noise Generated by Computers
Computers of today and tomorrow are increasingly fast and demand
far more powerful components. To ensure adequate cooling systems
to combat the generated heat, more powerful fans are required which
can produce serious amounts of unwanted noise. This noise can cause
significant problems, for example, a stack of several blade servers
can produce noise in excess of 85dB(A) which can be extremely difficult
and stressful to work next to, and will require action by law once
the European Directive is implemented in April 2006.
Initial sound wave (pure tone for this example)
Exact mirror image (similar but opposite phase)
Added together they 'cancel' each other out
Silentium's 'Silence in a Chip' Active Noise Control

Passive Noise Control Technology
Passive noise control has been used to good effect for a long time.
Acousti Products uses these methods in every product we produce.
Each product is optimised for noise reduction using sound-damping
acoustic materials, anti-vibration mounts and overall acoustic design.
Insulation materials are particularly effective in the middle and
high-frequencies of the sound range.
What is Active Noise Control?
The concept of Active Noise Control, or 'Anti-Noise' involves taking
a sound wave and producing an exact mirror image. By adding these
two sound waves together they "cancel" each other out
and the resulting pressure is zero so the waves hitting the ear
drum at the same time would not produce any sound.
If the high-pressure part of one wave lines up with the low-pressure
part of another the two waves interfere destructively and there
is no more pressure fluctuation, therefore no more sound.
Although this idea was recorded back in the 1930's it only came
into practical use with the advance of digital technology. A standard
Active Noise Cancellation System uses a sensor/microphone near the
sound source, a processor to compute the exact mirror of the original
sound, a speaker to emit the sound and error microphones to detect
when the system is not working and to correct it via the processor.
Active Noise Control can be particularly effective for low-frequency
sound waves.
Silentium's "Silence in a Chip"
Silentium Ltd have developed a revolutionary state of the art approach
to "Anti-Noise". Instead of using a sensor and microphone
near to the source, a chip is embedded AT the source of noise, virtually
altering the sounds directly.
This is achieved by utilizing smart proprietary algorithms, which
adaptively learn the environment and are implemented in real time.
This approach eliminates the need for error microphones. The result
is a small, low-cost yet highly effective solution to low-frequency
noise which can be applied to many different applications.
About AcoustiRACK Active
Acousti Products has teamed up with Silentium to produce a solution
to noisy rackmount equipment that is effective across the audible
spectrum, significantly reducing both low and high frequency sound
waves.
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