White Noise

White Noise

The Nature of White Noise and some of its useful Applications

Given the unfailing capacity of South Africans to turn almost any topic into a joke, whether familiar with its true meaning or not, the term white noise provides the joker with a unique opportunity for some irreverent and perhaps politically inappropriate humour. In reality, however, its meaning is somewhat abstruse and is unlikely to be fully understood without a reasonable knowledge of the physics relating to acoustics and signal processing.

Perhaps the simplest way to describe this phenomenon is as a random audible signal in which each of the frequencies from which it is composed is of exactly the same intensity. When this type of signal falls within the range of human audibility, a listener will experience it as a hissing noise rather like the “sh” sound. In this context, the name can be considered as akin to the term white light, which we also know to be made up of multiple frequencies even though the component colours are not visible to an observer without special equipment, or when they are dispersed by moisture in the atmosphere to form a rainbow.

More than just an interesting phenomenon, white noise has proved to be effective in a number of valuable applications. For instance, if you are among the many millions of unfortunate individuals worldwide that are plagued by the constant sensation of ringing in the ears known as tinnitus, there is every chance that you have been offered an electronic device with the ability to generate these random signals. The idea is that sustained exposure gradually enables the tinnitus sufferer to become less conscious of the inappropriate ringing and, in time, to ignore it altogether. Because of its overall neutrality, the random signal is easily ignored and causes the patient no significant distraction.

Another interesting application of these signals involves their use in determining the acoustic properties of a performance venue. In this situation, a public address system is used to deliver short bursts of white noise which is monitored from various positions within the building. By noting any areas that appear to boost or supress various frequencies, it is then possible by adjustment of the equalisation equipment to restore the correct sound balance. Surprisingly, perhaps, these same signals are often used as a source from which a music synthesiser can recreate the sound of a cymbal or a snare drum.

There is little doubt, however, that one of the most widely used applications is to be found in the workplace and can be particularly effective in open-plan areas and call centres, where extraneous sounds can often provide a constant source of distraction and may even affect one’s health. Here, the corrective mechanism is much the same as that applied to the treatment of tinnitus, differing only in that the masking effect of white noise is delivered, instead, via a speaker system. Studies have also shown that this technology can improve cognitive function. Overall, then, it offers the employer a means to create a restful yet more productive working environment.

Given the company’s established expertise in the field of audiovisual technology, it is hardly surprising that Elite Technologies has also made an impression in the workplace with its white noise speaker systems.