Active Noise Cancellation explained

Active Noise Cancellation explained

Active and Passive Noise Cancellation, how it functions, how it affects your music and headphones that use such technology. Read about Noise Cancellation in this basic Audiophile guide.
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It’s fun to tune out the humdrum of everyday life and let your favourite tune be the only thing you hear sometimes, isn't it? But, whether you’re in a closed space or an open one, ambient sounds around you can trickle into your headphones and annoy your li’l getaway. So how does one enjoy themselves without disturbance such as these? Say hello to Noise Cancellation technology.


 

First of all - what is ‘noise’ and how does one get rid of it? There are a number of misconceptions and misinformation about noise and the ways to eliminate it when talking about headphones. For starters, the term ‘noise’ here means external noise. Any sound which is not originating from the drivers in the housing of the headphone is technically known as ‘noise’ or ‘external noise,’ if you’re feeling fancy. This is obviously an undesirable element as it interferes with the music you’re listening to. Thus, we have Noise Cancelling technology. Noise Cancellation can be defined as those methods that are used for reducing or even attenuating unwanted noise. There are a variety of methods available that achieve noise cancellation/ isolation. Let’s take a look at the various tech and methods used for this.

Based on the method in which noise is reduced/ eliminated, there are two ways in which noise-cancellation is categorised: Passive and Active

Let’s talk about Passive Noise Cancellation. Known as Noise Isolation, this method does not actually cancel noise but reduces it to a great extent by isolating it. Meaning that passive cancellation is actually achieved by using sound-proofing or isolation and insulation. Plush fitting earphones, over-ear headphones with heavily padded earpads, closed-back headphones or custom in-ear monitors are all examples of noise isolation techniques. If you feel that your current pair of in-ears let in noise, you can even use ear tips from Comply to achieve better noise isolation. Closed-back headphones with fine padding give excellent isolation. Though a fairly effective method, noise isolation has a limit to how much it can cut out noise. Looking for something more? Head over to Active noise-cancellation.

Active noise-cancelling headphones can do everything that passive ones can't do. In Active Noise-Cancellation technology, the headphone features a chip that ‘listens’ to noise and generates audio that is opposite to it in nature(also known as Pink Noise) and thus canceling it. Sounds fancy? It’s simple physics really. Sound travels in waves. These waves have characteristics like amplitude and phase among others. Theoretically, if you fire a sound wave that is opposite in phase and of the same amplitude as an audio wave, you’d cancel the original wave out. Just think of it like those bow and arrow battles on serials like the Mahabharat! Two blokes fire an arrow at each other, the arrows meet in the middle and then fizzle out. Pretty much the same, except we’re talking about audio waves here. Noise cancellation is that little warrior dude that ‘takes care’ of noise. Period. They also add an extra level of noise reduction by actively erasing lower-frequency sound waves. When I say active, it means using additional powered instruments.

Noise-cancelling technology is used to reduce distracting background noise, providing an exceptionally comfortable and restful listening environment in areas with high ambient noise.

Active noise-cancelling headphones have components like:

Microphone – Noise-cancelling headphones feature a miniature microphone in the earpiece that picks up ambient noise (such as traffic, air-handling systems, etc.)

Noise-cancelling circuitry – Electronics in the earpiece create a noise-cancelling wave that is 180° out of phase (or opposite) with the ambient noise.  Result - It cancels out the annoying sounds that surround you without diminishing the audio you want to hear.

Battery – That’s an old saying in electronics - Where there be a circuit, there be a power source.

 

How does Noise-Cancellation actually help?

While noise-cancelling headphones do a good job distinguishing between the audio a user wants to hear and the background noise he or she wants to keep out, some people say that they compromise sound quality by muffling sounds. Also, the mechanism isn’t actually able to cut noises above 20dB. Ambient noises like aeroplane engines, closed trains are cancelled. Other louder noises cannot be affected by this technology as it would affect the audio performance of the headphone. Sudden sounds (like someone shouting at another) cannot be cancelled as well. Users can also experience a change in air pressure, although ports built into the ear cup are meant to vent air trapped behind the speakers.

 

If you are still thinking about getting a noise-cancelling headphone, make sure you spend some time with one first. Noise cancellation headphones are great but they aren't magic. A lot them require a bit of getting used to. So take your time and find the perfect getaway to your wonderful land of music.

Here are some of the best Active Noise-Cancelling Headphones:

 Sony WH-1000XM3

Bowers & Wilkins PX

Skullcandy Venue