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How Do Noise-Cancelling Headphones Work? ANC Explained

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Unless seeing your favourite artist live, nothing quite beats listening to music with headphones. Headphones make it easy to zone out from the world for as long you wish, focusing on nothing other than the mini-concert in your ears.

Headphones make listening to music on the go possible. For some, commuting without headphones would be unbearable; the same applies to those who need music to focus on a task. But, whatever your reason for wearing headphones, nothing quite ruins your listening experience like outside noise.

When wearing low-quality headphones, something as simple as a conversation or passing train can completely overpower your music. The mini-concert experience soon fades, leaving you frustrated and on edge. One of the many questions to ask yourself when buying headphones, do you need noise-cancelling capabilities?

What Are Noise-Cancelling Headphones?

As the name suggests, noise-cancelling headphones go the extra mile to reduce unwanted sounds. They allow you to achieve some much-needed peace and quiet, no matter where you are.

The main difference between noise-cancelling headphones and standard headphones is the techniques used to block noise. Noise-cancelling headphones use active noise control (ANC) to block out ambient sounds, whereas standard headphones will either use basic soundproofing or nothing at all. This means that if you wear standard headphones, you will likely hear other noises as you listen to music.

How Noise-Cancelling Headphones Work

Many of us can’t live without noise-cancelling headphones. Whether it’s to get some much-needed peace and quiet or to block out distracting noises, popping a pair of headphones on is often a saving grace. But how do noise-cancelling headphones actually work? We’re here to reveal all, but pay close attention, as the answer is a complex one (sorry!).

TL;DR

If physics and science go right over your head, take this bitesize snippet on how noise-cancelling headphones function, instead.

Noise-cancelling headphones use tiny microphones to pick up outside noise. The headphones then neutralise this noise by creating an opposite sound wave. By creating an inverted sound wave, the two sounds cancel each other out. This process is called active noise cancellation (ANC).

Understanding Sound Waves

Now – an explanation for the science lovers…

Before we pick apart the technicalities of noise-cancelling headphones, it’s essential to understand what sound actually is. This will make it easier to come to terms with how it gets blocked out. In comes physics…

Sound is a result of vibrations in the air. As these vibrations compress and decompress, they cause slight changes in air pressure. Our ears and brain then cleverly detect air pressure changes (also known as amplitude), converting them into sound. As expected, the louder the sound, the greater the amplitude.

Soundwaves On Monitor

Part 1: Active Noise Cancellation

The majority of high-quality noise-cancelling headphones use something called active noise cancellation (ANC). Brian Brorsbol, Director of Product Management at Sennheiser Communications, claims that ANC headphones can “turn down the volume of the world by about 30dB”. Pretty clever, right? If you’re sat wondering how this is possible, read on to find out more.

ANC uses something called “anti-phase” to cancel outside noise. When two sound waves are “in-phase”, they have the same flow, resulting in a louder sound. But, when two sound waves are “out of phase”, one wavelength is slightly delayed. This delay causes the positive and negative pressures to act against each other, cancelling out unwanted noise.

Part 2: Tiny Microphones

Headphones utilise the power of ANC with help from tiny microphones. The microphones (situated on the outside of your headphones) listen to ambient noise, signalling to the electronics in your headphones to cancel it out. Your headphones then create an opposite soundwave, using the “anti-phase” method to eliminate any outside noise.

While the mechanics behind noise-cancelling headphones can seem pretty complex, the end result is an immersive listening experience without any distraction! It’s amazing to see what tiny microphones and the rules of physics can do.

The Pros and Cons Of Noise-Cancelling Headphones

Many people fall for the misconception that noise-cancelling headphones eliminate all unwanted sounds. While this is the case to a certain extent, you’ll find that ANC actually just makes outside noises quieter, rather than eliminate them altogether.

With that being said, there are a huge number of advantages to wearing noise-cancelling headphones. To help to understand whether they’re right for you, let’s explore both the pros and the cons.

Pros

It’s safe to say that the most obvious advantage of noise-cancelling headphones is the ANC. With help from ANC, these headphones block out unwanted noise, allowing you to focus on what truly matters: your music. But greatness doesn’t stop there.

Here are some other pros of noise-cancelling headphones:

  • Adjustable cancellation (take control of the sounds you hear)
  • Comfortable volume levels (no need to turn it up loud!)
  • Suitable for travelling or commuting
  • Clearer sound

Cons

As with most products, there are a few cons of noise-cancelling headphones. However, you will soon see that these are incredibly minimal in comparison to the advantages.

  • High power usage (battery may die quickly)
  • Risk of ear damage (if you listen too loudly)
  • Slight sound distortion (due to cancelling out sound waves)
  • Higher costs

While it’s entirely up to you to decide whether noise-cancelling headphones are worth it, bear in mind that the ‘cons’ of them are manageable. They can charge in an instant and will last for many years to come.

Alternative Uses For Noise-Cancelling Headphones

Believe it or not, noise-cancelling headphones are used for a hell of a lot more than music. In fact, when they were first designed, music wasn’t even the picture! This might seem confusing to get to grips with, especially in a world dominated so heavily by music, but there was a method to the madness.

Music matters aside, alternative uses for noise-cancelling headphones include:

  • Aviation
  • As a sleeping aid
  • Assisting with autism

Aviation

Noise Cancelling Aviation Headphones

In the 1950s, Dr Lawrence Jerfome Fogel (the inventor of active noise cancellation) pitched forward plans to use ANC in aviation. He designed special headphones for pilots that reduced noise in the cockpit, making communication easier.

After flying success (pardon the pun) in the aviation industry, many other industries started to pick up on the power of noise-cancelling headphones.

Sleeping Aids

Headphones Sleeping Aid
Both passive and active noise cancellation headphones are used as sleeping aids. This is particularly helpful for those sensitive to sound or with insomnia, as less distraction from ambient sounds will make it easier to fall asleep.

Nowadays, you can buy noise-cancelling sleep headphones and earplugs. This makes it easier to block out noise while sleeping without worrying about wearing bulky music-focused headphones.

Autism

Recent studies have found that noise cancellation headphones can help children with Autism Disorder. Results concluded that the headphones helped children to cope with problems related to hypersensitivity.

Are Noise-Cancelling Headphones For You?

From listening to your favourite tunes in peace to assisting with sleep, there are many reasons to invest in a pair of noise-cancelling headphones. As lovers of music, we’re probably biased in saying it’s a no-brainer to get some, but if you want a solitary music experience, ANC headphones are the way to go.

Wave goodbye to annoying noise disturbances and say hello to a bliss listening experience. We know you won’t regret it.

Kelvin Wan
Kelvin Wan
Kelvin is Upbeat Geek's audio tech expert. He keeps in the loop with the latest releases from soundbars to earbuds. Kelvin enjoys travelling and concertgoing, and has a creative career is fuelled by music - a wide array of it we must say. Kelvin's always been a tech head, working with and reviewing different audio setups, from speakers and amps to any type of headphone you can think of. He knows how to uncover the science behind the tech and explain it in 'me and you' terms. His favourite artists consist of Coldplay, Dave, Justin Bieber, Kanye West and Woodkid, (we told you it was a wide array!)

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