Best Noise-Cancelling Headphones: How Does Noise-Cancelling Work?

Headphones have become a must-have item. After all, no one wants to spend an entire commute listening to a rumbling bus engine. And for some reason, even when out for a walk, we’d rather listen to a gruesome true-crime podcast than the gentle rustling of leaves in the breeze!

So if you’re looking for a way to block out the sounds of the real world, which noise-cancelling headphones are best? And how does noise cancelling work?

What are noise-cancelling headphones?

Noise-cancelling headphones were first made for pilots on long flights. Designed to block outside noise (such as the constant drone of plane engines) they create a sealed, quiet environment to deliver the best listening experience.

How do noise-cancelling headphones work?

When we talk about noise-cancelling headphones, we’re actually talking about active noise cancellation (ANC). This differs from passive noise cancellation (PNC) or noise isolation as it’s often called.

PNC works by physically blocking out sound. For example, how a pair of headphones that entirely cover your ears and sit snuggly around them physically block out noise. This is no different to cupping your hands over your ears. While it effectively muffles and lowers the volume of outside noise, it hardly cancels it out.

Without getting too technical, active noise cancellation works by picking up outside noise with a microphone and actively neutralising it. This is done through a clever process called phase inversion.

If you picture a soundwave, it looks like a wobbly line with peaks and troughs. If you add a second identical wave, these peaks and troughs line up, creating an amplified (louder) signal. (as shown below).

But with phase inversion, the headphones analyse the soundwaves of the unwanted noise, and produce their own counter-wave, 180 degrees out of phase. When the two waves are 180 degrees out of phase they are inverted (as shown below).

This creates an effect similar to adding +1 and -1. You’re left with zero. By adding the equivalent opposing soundwave, you create what is called destructive interference, neutralising, and silencing, the unwanted noise.

While effective, it’s worth noting the technique isn’t foolproof. Noise cancellation works better with low ambient frequencies – the hums and rumbles of engines, appliances, air conditioners etc. – than it does for higher ones. And while it can certainly turn down the volume of the outside world (typically by about 20-40 decibels) it won’t plunge you into total silence.

It’s also worth noting that ANC is typically used in conjunction with PNC. For example, your active noise-cancelling headphones will likely have padded cups that sit over your ears or, in the case of earbuds, little silicon tips that help create a seal in your ear canal.

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What are the benefits?

Firstly, it’s worth noting that noise cancelling doesn’t inherently improve the sound quality of your headphones. It simply minimises the outside noise, which delivers a better audio environment. But a pair of noise-cancelling headphones can still produce low-quality sound with muddy bass and tinny highs! You’ll just have the benefit of hearing the bad sound quality better than ever!

However, there are several benefits to active noise cancellation:

• A better listening experience – without outside noise, you can hear your music clearly and uninterrupted, creating a more enjoyable experience
• It’s better for your hearing – you don’t need to use volume to block out outside noise, letting you play music at a lower volume, which is better for your hearing
• Can be used for peace and quiet – noise-cancelling headphones don’t require you to play any music to work. This makes them popular for blocking out unwanted sounds in general. For example, when walking next to a noisy highway, trying to focus in a noisy office, or even meditating
• Can help your overall health – our world is noisier than ever and this has been linked to a lot more than just hearing loss. Migraines, ulcers, high blood pressure etc can all be linked to noise stress

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Best noise-cancelling headphones

Sony WH-1000XM5 ($545*)

A beautiful and minimalist pair of headphones (clad in a soft, vegan leatherette) the Sony WH-1000XM5 is often seen as the main rival to the trendy and popular Apple AirPods Max. Although in truth, most audiophiles will tell you these are arguably better (and definitely cheaper). Although, there’s no doubt the Apple AirPods offer a seamless and unrivalled iPhone experience (more on this below).

The Sony WH-1000XM5 has some of the best ANC on the market, and with this (and the excellent yet comfortable seal around your ears) you’ll be revelling in the near silence of the world around you. Even better yet, its excellent battery life gives you 30+ hours of ANC use.

Other neat features include the ability to allow ambient noise through by cupping your hand over the earphone. This is excellent if you have a colleague or child frequently bugging you with questions and/or comments. You can listen to what they have to say without having to take off the headset.

Do note that these have no official IP rating, but Sony advises that these headphones are no friend to sweat or water. So pumping gym sessions and dramatic walks in the rain are off-limits.

Bose QuietComfort 45 ($385*)

Bose QuietComfort 45 noise-cancelling headphones have some of the very best ANC out there. But while these headphones certainly sound good (and some say even excellent) the sound quality isn’t up there with other headphones on this list. So they may not be the best choice for music snobs.

On the other hand, they are a great option for those who want the best in noise-cancelling, plan to use their headphones to block out noise (while not playing anything) or prefer podcasts over pop! Or simply for those wanting a relatively cheap pair of good-sounding ANC headphones.

Sennheiser Momentum 4 Wireless ($488*)

Sennheiser has long been associated with premium sound quality and equipment. And these headphones live up to the Sennheiser tradition. Ditching the trend of booming bass (which often comes at the expense of clear and full mids) the Momentum 4 Wireless offers balanced, rich sound.

The noise-cancelling is effective and it even has an ANC Adaptive mode. This is designed to automatically adjust the noise-cancelling effect in real-time based on noise fluctuations in your environment.

To top it off, 60+ hours of battery life gives you double what other popular headphones offer.

Apple AirPods Max ($999*)

Absurdly priced yet absurdly popular is nothing new when it comes to Apple products, but the AirPods Max might sit at the top of that list. Roughly double the price of every other pair of headphones on this list, the AirPods Max is a premium pair of headphones that are as much a fashion accessory as they are a pair of headphones.

Don’t get me wrong, these headphones sound great, offer excellent ANC, look great and feel great to wear. But whether they justify their price depends on you and your needs.

→Related article: AirPods vs AirPods Pro: Which Should You Buy?

For example, if you want something for the gym, well these aren’t waterproof (the excellent and IP-rated Apple Airpods Pro are your best option there). And if you want the best of the best when it comes to sound quality, then a wired pair of studio headphones will likely serve you better (although practicality and portability may be hindered).

But if you want everything Apple, you want the headphones the celebrities wear, or you just want something that seamlessly integrates into your network of Apple devices better than anything else, all while offering premium sound quality and ANC, then this is an excellent pair of headphones.

But whether it’s any more excellent than, say, the significantly cheaper and already premium Sony WH-1000XM5 (device integration aside) is debatable.

What about earbuds?

It’s worth noting that noise cancellation isn’t exclusive to headphones. Many premium earbuds now feature ANC and for many, are a better option. Not only are they smaller and more portable (easily thrown into a pocket or handbag) but they typically offer better IP protection, making them suitable for winter walks and gym workouts.

Better yet, many of the above headphones have earbud iterations!

Some popular earbuds with active noise cancelling are:

• Sony WF-1000XM4
• Bose QuietComfort II
• Apple AirPods Pro
• Galaxy Buds2 and Galaxy Buds Pro/Pro2

Streaming takes data

While you can download music ahead of time, the best way to get the most from your music streaming service is to have boatloads of data to support your streaming habits. Sharing music with friends, finding new favourites, and browsing specially curated playlists are all part of what makes music streaming great. If you’re away from a wi-fi connection, you’re going to want enough data to keep the tunes coming.

And as part of that, you’ll want the best phone plan. That’s where Canstar Blue can help. We compare phone plan providers, to get you the best deals on your data. To learn more, or start comparing, just click the button below:

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About the author of this page

This report was written by Canstar Content Producer, Andrew Broadley. Andrew is an experienced writer with a wide range of industry experience. Starting out, he cut his teeth working as a writer for print and online magazines, and he has worked in both journalism and editorial roles. His content has covered lifestyle and culture, marketing and, more recently, finance for Canstar.