Ever wondered how noise-cancelling headphones work?

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You might have been curious about this for a long time, who knows. Whenever you are listening to headphones in a noisy environment, you certainly might feel inconvenienced unless they are noise-cancelling. The noise of the neighbour walking their dog which barks too much will never disturb you again with noise-cancelling headphones. So maybe you are curious about how they work.

To get a grip of how headphones work, you need to understand how sound works.

A sound wave can be related easily to a wave in the ocean, except for the fact that a sound wave is longitudinal. When you play a piano, strings under the hood of the piano begin to vibrate and it causes a sound. The strings are pushing and pulling air, leaving packets of air with a little higher density, and packets with lower density.

If you have ever tried listening to a disc player on an aircraft during flight, you know exactly why you need noise-cancelling headphones. Noise-cancelling headphones can make the sound coming from your audio device more pronounced.

There are two types of noise-cancelling headphones: passive and active. To give you a clearer idea, almost every headphone is able to cancel noise passively. This is because the foamy material on the headphones blocks out extra sound coming from outside. If you have ever seen a heavy pair of headphones that has a foamy pad that rests around the ear of the listener, you have seen a pair of passive noise-cancelling headphones. These headphones, however, cannot cancel some high-level noises you might encounter, such as the roaring of a jet engine. Active noise-cancelling headphones can correct this problem.

Active noise-cancelling is a very interesting subject. Basically, headphones that have this feature are built like passive noise-cancelling head phones, but they also “erase” other sounds from outside. They basically listen in on the sound that is going on outside, and produce a faint sound wave that imitates noises from outside, in a way that will completely cancel their sound. This is done by de-phasing the sound waves coming in by 180 degrees.

The only disadvantage that active noise-cancelling headphones have, which can be overcome by passive ones, is that they require a battery. Battery life is usually high on these headphones, but it is not always practical to depend on battery life for both the headphones and the audio device.

If you are planning to buy noise-cancelling headphones, just have these things in mind, and I hope this article provided you with some decent advice. 

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