How Do Noise-Canceling Headphones Work?

Noise-canceling headphones are all the rage these days. Just turn on your TV and you’ll likely see adverts for pricey earbuds touting the latest and greatest in noise cancellation technology!

It’s not hard to see why these gadgets are so popular. Noise pollution can be headache-inducing while making it impossible to hear your jams.

how do noise-canceling headphones work

A solid pair of noise-canceling cans will let you enjoy your music in peace! But how do noise-canceling headphones work? Read on to learn more!

What Exactly is Noise Cancellation?

To put it in broad strokes, noise cancellation is the process of reducing or eliminating sounds.

While the technology is primarily used for consumer headphones, it’s been around much longer than most people know. Its earliest form started all the way back in 1933! Doctor Paul Lueg submitted a patent that would continue to evolve in the coming decades.

The first active noise-canceling headset was created by Doctor Amar Bose. Does that name sound familiar? Bose would go on to develop headsets for military pilots and aviation professionals. He also created the Bose company, which continues to dominate the audio industry.

Noise cancellation is a lot more than simply blocking out unwanted sounds. It’s a highly advanced piece of technology that counteracts noise by manipulating the waves before they can hit your ear.

The Magic Behind the Noise-Canceling Feature

The concept of noise cancellation sounds pretty simple, right? Well, the technology that makes it happen is anything but!

To understand how cancellation works, you have to understand how sound works!

Sound is produced when something vibrates. This could be your vocal cords, an instrument, or the hull of a plane!

Those vibrations then propagate through the air and create variations of pressure and an acoustic wave. When those sound waves hit your ear, they travel through your ear canal and hit the eardrum. The eardrum then vibrates and sends signals into your middle ear.

Here’s where the magic comes in. Noise-canceling headphones step in to manipulate those sound waves before they hit your ear.

Depending on the type of technology used, the headphones can actively change the physics of the sound wave or they could physically stop it. Some high-end headphones do both and continually adapt to provide the best noise reduction possible.

Three Types of Noise Cancellation

The term “noise cancellation” is thrown around pretty sparingly these days. This is especially true in marketing.

The truth is, there are three different forms of noise cancellation on the market today. The results they provide are dramatically different.

1. Passive Noise Cancellation

The first type is the most basic. Passive noise cancellation reduces noise by insulating your ear. It doesn’t utilize any advanced technology or power. Instead, it relies on pure physics.

Think of it as a form of soundproofing. But instead of soundproofing a room, you’re soundproofing the area around your ear.

Headphone manufacturers achieve this by adding density and mass around a circumaural earcup. You might see thick foam padding that conforms to the shape of your head. The heavyweight material suppresses sound waves and reduces their speed.

You might also see a closed-back design or additional materials to create a tight seal. The goal here is to force sound waves through the insulating material.

The final result is a noticeable reduction in volume.

It’s a pretty rudimentary form of sound cancellation. In fact, it shouldn’t be called cancellation at all. Many headphone brands refer to it as passive noise reduction instead of clarity.

2. Active Noise Cancellation

This is the truest form of noise cancellation. Active noise cancellation, or ANC, uses advanced algorithms and state-of-the-art technology to block out sound.

We’ll get into the technical details in the next section. For now, the important thing to know is that ANC uses external microphones to measure background noise. Then, speakers inside the headphones produce destructive sound waves to reduce the volume of unwanted sound.

It’s a power-heavy technology, but it’s also the most effective. Instead of relying on physical barriers, ANC changes the characteristics of the sound wave to provide results.

3. Adaptive Noise Cancellation

This is a newer technology that has been making waves in the audio community. It’s very similar to active noise cancellation. However, the brains of the system are much smarter.

Big-name tech companies have developed chips that can estimate sound signals and adapt the levels of cancellation accordingly. The headphones will fine-tune the destructive frequency based on your environment.

Say, for example, that you move from the low rumble of a subway train up to a busy street. With adaptive noise cancellation, the transition is seamless. Newer headphones can even monitor any issues with the seal of the earcups and make changes to give you the best results possible.

This technology is continuing to evolve. Some brands are implementing smart features that let you adjust the level of noise cancellation. While not perfect just yet, it’s a great way to let voices or intercom announcements through while still blocking out basic background noise.

How Do Noise-Canceling Headphones Work?

True active noise cancelation is far more complex than most even realize!

Headphones with active noise cancellation have an external microphone, a battery, a processing chip, and an internal speaker inside the earcup. All of those components work together to achieve effective phase cancellation.

Earlier, we talked about how sound travels in a wave to get to your ear. You can’t physically see those waves, but they look like waves of the ocean. They have peaks and troughs, which are referred to as the amplitude of the wave. The amplitude dictates loudness.

The waves also have a specific wavelength, which is measured from peak to peak. Wavelength determines the frequency or pitch.

Why does this all matter? Well, active noise cancellation systems measure the parameters of sound waves coming in from outside of the headphones. Those waves are picked up by the microphone and quickly processed.

Then, the headphones produce a nearly identical wave inside the earcup. The only difference is that the new waves are 180 degrees out of phase. It’s essentially a mirrored version of the sound wave. Where there are peaks from the external sound waves, the headphone will produce troughs and vice versa.

When those two waves combine to hit your ear, they cancel each other out. This is known as phase cancellation or destructive interference. It truly is an impressive piece of technology packed inside your headphones!

Active noise cancellation can’t achieve 100 percent cancellation. But, it will attenuate the sound by 20 to 30 decibels.

The Pros and Cons of Noise-Canceling Headphones

A little peace and quiet when you’re getting lost in the music is always a good thing! But, noise-canceling gear isn’t perfect. The technology is still evolving. While very effective in some situations, these types of headphones aren’t for everyone.

Here are some pros and cons to mull over if you’re still on the fence.

Pros

The most obvious benefit of these headphones is a more enjoyable listening experience. Even with headphones in, there’s no getting around some noises.

Low-frequency sounds, such as the hum of an airplane engine or general street noise, tend to stand out when you’re listening to music. Luckily, active noise cancellation technology is most effective for those sounds. It performs best when there’s constant noise in the background.

It’s great for travel and can help you hear those subtle details in your music that’s usually lost. That also makes sense if you use your headphone for producing and mixing.

Another advantage of noise cancellation is that you don’t have to pump up the volume to dangerous levels. Some devices can produce upwards of 120 decibels. Prolonged exposure to sounds above 70 decibels is enough to damage your hearing.

Because the background noise is reduced with noise cancellation, you can keep your music at safe levels while still having the level of enjoyment you’re after.

Cons

Noise-canceling headphones do a lot of good. But, they won’t block out everything. As we said earlier, they do their best with low-frequency noises below 1 kHz. For noises above that, the effectiveness of the headphones starts to wane a bit.

Not only that, but it takes time to process the information picked up by the microphone. So, sudden high-frequency sounds, such as a dog barking or a car horn, often make their way through. Headphones are getting better with every passing year, but most models today are still going to produce some artifacts and distortion during those sounds.

Some people who try out these headphones also experience discomfort. A unique psychosomatic phenomenon known as Eardrum Suck affects some users. It feels like a sudden pressure change in your eardrum.

While the phenomenon is largely just the mind playing tricks, it doesn’t make the pain any less real. Many people report getting headaches or feeling nauseous.

The phenomenon doesn’t affect everyone, but it’s certainly something to consider.

Are Noise-Canceling Headphones Safe?

Eardrum Suck aside, noise-canceling headphones are perfectly safe to use. They don’t cause any real ill-effects. In fact, they can improve your health by protecting your ears!

Both passive and active noise-cancellation will reduce the volume of background noise and transient sounds. This is beneficial for a few different reasons.

For one, it helps you avoid turning the volume up to dangerous levels as we mentioned earlier. That alone is going to reduce your chances of experiencing hearing loss.

On top of that, noise cancellation technology can reduce the harmful effects of low-frequency noise. Studies show that prolonged exposure to low noise, even if it’s not super loud, can increase stress levels.

Plain and simple: noise cancellation protects your ears and can preserve your hearing.

Conclusion

Who knew that so much technology was hiding inside noise-canceling cans? This technology has completely changed the face of consumer audio gear.

Not only has it made headphones a premium item to invest in, but it gives music lovers the chance to truly appreciate their music. Whether you’re on a busy train or want to drown out background noise as you work, noise cancellation headphones have you covered.

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