1. Computing
Send to a Friend via Email

Noise Cancelling

The Elimination of Unwanted Sounds

By

We are surrounded everyday with unwanted noises. These affect the quality of our voice communication, either through headphones or naturally, and also affect our personal tranquility. Think of the noise pollution in a busy street, crowded place, flight, factory machinery etc, and imagine the perspective of having to work there a whole day.

Noise cancelling, or noise cancellation, is a technique used in modern headphones that attempts to cancel out or reduce the unwanted ambient noises around us. Traditional methods of eliminating noises, like covering the ears with pads or closing doors, only prevent the sounds from reaching our ears. Noise cancelling works by destroying these noises in the air.

How Noise Cancelling Works

Sound travels in air in waves, which have peaks and valleys. They are not as smooth as the sine waves you are picturing in your mind, but these are good examples to understand the concept. Each type of sound has a frequency that determines the size of the waves. Noise cancelling mechanism involves capturing these unwanted sound waves, analyzing them and generating other sound waves of the same amplitude and frequency but inverted. Consider these generated inverted sound waves as anti-waves. When the two sound waves meet, the peak of one couples with the valley of the other, and vice-versa, for every cycle. Thus, they cancel out each other, and the unwanted sound is killed, leaving only silence.

Noise Cancelling Headphones

Noise cancelling is implemented in modern headphones, and is one of the most demanded features. These headphones have tiny microphones near their earpieces, close to the person’s ears. They capture the unwanted noise waves from the environment. Transmitters fitted within the same mechanism emit sound waves that will cancel the noise, thereby leaving the person’s ears free for the pure sound that comes from the ear pieces, be it music or a voice call.

Problems with Noise Cancelling Headphones

The energy requirement for noise cancelling headphones is more than simple ones. This consumes battery power and affects battery autonomy in headphones that are designed for other uses, like wireless headphones used for VoIP communication.

Also, inefficient sound cancellation may result in different sounds that cause another kind of disturbance. It may also affect the sound quality of the desired sound.

However, sound cancellation is getting more and more sophisticated, and the recent models of sound cancelling headphones are very efficient, be it on sound quality and battery autonomy.

So while buying a headphone, consider noise cancellation as a feature to look for.

©2014 About.com. All rights reserved.