Ever needed to concentrate on something you are listening to, but the environment around you just could not let you? You probably thought of, or even acquainted yourself with, noise cancelling headphones. But do you know how they work? Or is it just a phenomenon we should take as it is?
Probably this inquiry should base on the difference between the normal headphones and the noise-cancelling pieces.
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One key note to take is that these noise reducing headphones are categorized in two, depending on their work; passive and active.
Passive Noise Cancelling headphones
Typically, any type of head-phones can cancel noise passively because the materials in them are capable of blocking out external sound waves, especially if they come in at higher frequencies.
They are closed-back and sealed to reduce noise passively by physically covering the listener’s ears to help block out external noises.
They have an in-ear design that forms an acoustic seal that helps to block background noise and allow for more accuracy at lower volume levels.
Active Noise-cancelling headphones
These do everything the passive headphones do but go ahead to employ active noise-cancelling technology to cut down any distractions from the background, giving a listener a remarkably comfortable listening experience when surrounded by high ambient noise.
They have elements that are not present in your ordinary pieces such as a miniature microphone in the earpiece that picks up ambient noise like in traffic, air-handling systems that cannot be blocked passively.
There is also a noise-canceling circuitry in the ear piece that creates a noise-cancelling wave that is 180° out of phase with the ambient noise wave. When the two waves meet, they cancel each other out in a phenomenon known as destructive interference.
The noise-cancelling wave basically acts like a noise eraser as it cancels out all the sounds that surround you without diminishing the audio you want to hear.
The headphones listen to the background noise around you and process it as a sound wave. They then create sound that is exactly opposite to that sound wave and this cancels it out so that all you hear is the music coming from your headphones and not anything from the outside.
Not to forget, with a rechargeable battery, the head phones can produce the noise-canceling effect.