Headphones and earbuds used to be pretty basic. They had only one task: to make music. But a relatively new feature called ANC, or “active noise cancellation,” has turned everything on its head. It’s now impossible to buy headphones without stumbling upon this feature that claims to reduce background noise in any environment. And let me tell you, ANC is great.
Here’s the problem; ANC headphones or earbuds tend to cost a lot of money, and no one wants to spend more on something they don’t understand. Because of this, it’s time to familiarize yourself with how ANC works and assess any limitations or issues that you might encounter while using ANC.
What is active noise cancellation?
Because headphones and earbuds cover your ears, they all provide some Level of noise cancellation. But this “passive” cancellation isn’t very effective, especially if you’re on an airplane, in a noisy office, or next to an air conditioner.
And that’s where ANC, or “active noise cancellation,” comes in. Headphones or earbuds with ANC don’t just cover your ears; They also use digital processing to reduce background noise. The result is truly stunning as ANC can instantly transform a noisy environment into a quiet sanctuary.
Most high-end wireless headphones and earphones now come with ANC, although the feature tends to work quite well even on affordable products. Additionally, some headphones and earbuds allow you to adjust the ANC intensity via an app, which is a handy feature if you only want to turn off certain sounds.
If you’re ever in a noisy environment that’s uncomfortable or distracting, ANC is an essential feature to look for in a new set of headphones. But how does ANC work and is it always a good thing?
How does active noise cancellation work?
You probably know that sound travels in “waves” like light. And although light and sound are two very different things (light is radiation, sound is pressure), their respective waveforms work in similar ways.
We will focus on the waveform frequency as this is the most important part of understanding ANC. In unscientific terms, frequency is the speed at which a wave wobbles. For example, low-frequency light waves are red, and low-frequency sound is low-pitched.
Oddly enough, low frequency waveforms are also very good for space travel. This is why the sky looks red in the evening. And unfortunately, it’s also why your neighbor’s music blares through your home. An old-fashioned pair of headphones can “passively” block high-frequency noise, but it can’t protect your ears from low-frequency noise, so something advanced like ANC is needed.
Now that you know a little bit about waveforms, the science behind ANC is actually quite simple. Basically, headphones or earbuds with ANC use microphones to capture external noise. Then they reverse the polarity of that noise (they flip the waveform upside down) and pump it into your ears. Because sound is a form of pressure, the “Anti-Noise” wave physically cancels out any distracting background noise that manages to penetrate your headphones.
The effectiveness of ANC headphones or earbuds may vary by design. For example, a high-end pair of headphones may use external and in-ear microphones. The external mics allow your headphones to quickly respond to noise, while the in-ear mics “hear” any low-frequency rumble that manages to reach your ears. (Some headphones use in-ear mics to detect when an ANC signal isn’t working properly.)
Earbuds rarely have room for in-ear mics, so they’re often less accurate than full-size ANC headphones. So ANC earbuds can respond quickly to external noise, have a harder time canceling out low-frequency rumble, and can’t self-correct when something goes wrong.
Does ANC affect the sound quality?
Unfortunately, you can’t use ANC without sacrificing sound quality. The technology isn’t 100% accurate, so you can expect some noise with most headphones or earbuds when you turn on ANC. You’ll also notice a decrease in sound quality if the headphones aren’t able to properly seal your ears.
And if you’re a born audio sleuth, you might notice a change in the audio loyalty when you activate ANC. That’s because your headphones need to add an “anti-noise” ANC signal to your music, which requires digital processing. While this processing shouldn’t harm your music, it does require additional power consumption that can cause some problems.
With a pair of wireless headphones or earbuds, using extra power will dramatically decrease battery life. Manufacturers are forced to split the difference. Otherwise, customers complain that their headphones don’t work long enough. So when ANC is active, the drivers in your headphones receive less power, reducing dynamics and frequency response but increasing battery life.
Headphones and earbuds typically apply an EQ to music when ANC is active, which can affect the audio quality change. Often this trick doesn’t work, although high-end headphones that go through a lot of development can sound the same whether ANC is active or not. (The change in audio quality is most noticeable in budget earbuds, largely due to cheaper hardware and a lack of research and development.)
By the way, wired headphones are not free from this problem. Most wired ANC headphones contain a battery because the “passive” signal of a 3.5mm cable cannot power a digital audio chip. When this battery is activated, it changes the amount of power available to the headphones’ drivers, changing their sound profile.
Are ANC headphones comfortable?
When people try ANC for the first time, they may feel a strange “pressure” in their ears. It’s a strange phenomenon that can be painful for some people, although it usually goes away once you get used to the feel of ANC.
As with all things in life, the human brain is responsible for this problem. Our brain partially relies on our ears to detect changes in air pressure. So when a pair of ANC headphones cancel out a rumble (especially one that’s loud and sustained), it can trick our brains into believing the air pressure has suddenly changed.
People typically pop their ears to cope with changes in air pressure. However, this does not change the feeling of wearing ANC headphones. As a result, you may feel a little uncomfortable using ANC.
Again, this problem usually goes away once you get used to wearing ANC headphones or earbuds. But some people just aren’t built for ANC. Luckily, ANC mode is optional on your headphones, so you can turn it off at any time.
The opposite of ANC: transparency mode
Now that ANC is a relatively common feature, headphone manufacturers are looking for other ways to make their products stand out. A new feature that is actually the opposite of ANC is usually referred to as transparency or ambient mode.
Transparency mode picks up external noise and pumps it into your ears so you can hear your surroundings. It may sound counterintuitive, but transparency mode can help you avoid unwanted or dangerous situations when you go outside, go to the gym, or use public transport.
Of course, this function is not just for security. You can use transparency mode to hear family or friends, for example, without pausing your music. I actually use it when cooking because it allows me to hear food sizzling in the oven or simmering on the stovetop.
I should also mention that like ANC, the transparency mode is usually customizable. In some cases, headphones or earbuds even have a transparency setting that focuses on voices and ignores other external noise.
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