If you’ve ever had to listen to the sound of a plane turbine for 8 hours or tried to make an urgent deadline while your co-workers are busy discussing Bird Box, you’ve probably wished that the world around you had a mute button.

While they’re not a perfect mute button, noise-cancelling headphones can drastically lower the noise around you -- in some cases by as much as 80 decibels.

They work using a concept known as destructive interference to effectively remove outside sounds from what you want to hear.

If you’ve ever wondered how these headphones work -- and if they’re worth buying -- this guide has you covered.


Noise Cancelling vs Noise Isolation? What’s the Difference

This guide is going to focus primarily on noise cancelling headphones.

So, before we get started, it’s important to understand the difference between these noise cancelling and noise isolating headphones.

Noise isolating -- or passive noise cancelling -- headphones work by blocking outside noises. Kind of like if you cupped your hands over your ears.

This is often done using thick ear cups or snug-fitting earbud tips to keep sound waves around you from reaching your ear drum.

Most noise isolating headphones top out around 20 decibels of background noise reduction.

If you need more reduction, you’ll need to check out noise cancelling headphones.

[DECIBEL RATING IMAGE]

Noise cancelling -- or active noise cancelling -- headphones are very different from noise isolating headphones. They essentially use technology to eliminate the ambient noises surrounding you.

If you’re listening to music or watching a video, you’ll be able to hear better. But most models will also allow you to put the headphones on with no input at all and simply enjoy a bit of peace and quiet.

They are capable of reducing overall noise by as much as 80 decibels depending on the model.


So How Do Noise Cancelling Headphones Work?

Noise cancelling headphones use digital signal processing (DSP) to work their magic.

There’s a microphone -- or microphones -- embedded in the headphones . They’re often in the ear cups for over- or on-ear models and in-line for earbuds or in-ear models. So if you’re worried about appearance, they don’t stick out like a mic on gaming or bluetooth headsets.

This mic records the ambient noise around you and sends it to the DSP chip. The chip then creates a signal that is audibly opposite to the noise around you.


When it’s played back to your ear with the audio from your phone, tablet, or whatever you’re listening to, the result is a dramatic reduction in outside noise.

This is known as destructive interference. While that might sound frightening, it’s perfectly safe for your ears. But it can slightly reduce audio quality -- even on the best noise cancelling headphones.

For cheap models, it might not just degrade quality, it could even introduce additional noise to your audio stream. So definitely read reviews to get an idea of how any headphones you are considering will perform.


Do Noise Cancelling Headphones Actually Work Though?

Yes they do. But it’s important to set expectations.

Active noise cancelling headphones aren’t magic noise eliminating machines… but they can definitely help in the right situation.

Because of the science behind destructive interference, it tends to filter out bass-heavy, steady noises best -- such as train or plane noises.

Most decent noise cancelling headphones can also handle lower volume conversations and similar background noise, but you won’t find a pair of noise-cancelling headphones that perfectly remove loud conversations, TV dialogue, or music from your surroundings.

Noise cancelling headphones also do not hand handle loud, sudden sounds well. So doors slamming or kids yelling will still come through in your audio feed.

So, in most cases, you actually want a pair of headphones with both passive and active noise cancelling abilities.

What slips past the DSP will hopefully end up muffed, if not eliminated, by the design of the headphones itself.


Common Questions










Summary

As long as you don’t expect total silence, noise cancelling headphones can offer some much needed quiet in today’s busy world.

Noise isolating headphones don’t offer the same level of noise reduction but are substantially cheaper.

However, if there’s room in your budget, a good pair of over-ear active noise cancelling headphones are a great way to eliminate office noise, the endless hum of plane engines, air conditioners, and other common distractions and allow you to rest better or focus on what you’re listening to.

In-ear active noise cancelling headphones are better suited for on-the-go use or when you prefer a less obvious option for listening.

Regardless of your pick, be sure to check headphone reviews and -- if you can -- try a few pairs at a local retailer. This will ensure your choice is a good fit for your ears and hearing.


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REFERENCES:
[1] Forbes : Are Noise Cancelling Headphones Worth It?
[2] How Stuff Works : How Noise-Canceling Headphones Work
[3] Sound Guys : How Do Noise-Cancelling Headphones Work?
[4] Audio Technica : How Do Active Noise-Cancelling Headphones Work?
[5] Mental Floss : How Do Noise-Canceling Headphones Work?
[6] Cnet :How Do Noise-Cancelling Headphones Work?
[7] Scientific American : How do Active Noise Canceling Headphones Work?
[8]Wikipedia : Active Noise Control