What Are ANC Headphones?

Just a few days ago, Apple came out with its own brand of truly wireless over-ear headphones, the AirPods Max. They’re priced at $550. At this time, several companies including Sony (WH-1000XM4s). Bose (Bose 700), and Sennheisser (Momentum 3 Wireless) have their own offerings.

Several companies are also competing in the wireless earbuds (in-ear headphones) department. Samsung has its Galaxy Buds+ and Galaxy Buds Live, Apple has its AirPods and AirPods Pro. Sony has its WF-1000XM3s, and the Jabra Elite, and the JayBird wireless earbuds are all selling at competitive prices.

However, all of these headsets or headphones have one feature in common. They focus on noise-isolation, or noise cancellation. 

What Does ANC Stand for on Headphones?

ANC, or Active-Noise Cancellation refers to a technology that tunes out ambient noise. By doing so it headphone user is further immersed into the sounds emanating from the headset. Director of Product Management at Sennheiser Communications, Brian Brorsbal, says ANC turns down the surrounding volume by approximately 30 dB. 

“Using noise-cancelling technology on its own is something we’ve heard some people are doing,”-Brian Brorsbal

Clearly, ANC is more popular as a feature than you’d think. Certain people use ANC to block out ambient noise during flights or during times of stress. Scientific research has shown that this actually works, both during music playback as well as without. In fact, you might even think that sound quality has taken a backseat to noise isolation. As long as sound quality is decent, people don’t really care about how much clearer they can listen to music. Apart from the most dedicated audiophiles, you won’t even find many people adjusting their equalizers.

Tuning out the world and simply enjoying music as an immersive experience has become a luxury today. With all the notifications we receive every day, the noise of the big cities, etc. sensory overload has become the norm. Hence, ‘true wireless earbuds’ featuring noise cancellation have become essential for tech-heads.

However, as with all types of technology noise isolation is not all the same.

All ANC Is Not Created Equal

ANC focuses on recording sound through microphones and using that input to tune out the outside world. However, there’s more than one way to do that. As you may have seen with the latest Apple AirPods Max announcement, there are 9 microphones inside that headset. For other headphones, there may not be as many microphones, but does that really affect the quality of sound?

There are three basic ways to implement noise cancellation on headphones. 

  • Feedforward ANC
  • Feedback ANC
  • Hybrid ANC

Feedforward ANC

Feedforward setups use a microphone that is placed outside the earcup. The microphone hears the noise before the user and processes the noise to create ‘anti-noise’. After that, a signal is sent to the speaker in the headset. As a result, the user hears much less of the noise and is better immersed in music.

Since the mic is on the outside of the headset, it can process and generate anti-noise before it reaches the human ear. Hence, it can reduce higher frequency noise better, up to 1-2kHz.

However, there are disadvantages to this approach. There is no self-correcting setup here. Since the headphones don’t hear the anti-noise they create, they can’t correct any problems with it. Hence, if the headset ever goofs, it can’t reprocess the noise.

If the noise is coming from a different angle than the microphone, the mic can actually amplify it! Also, since feedforward ANC works with a narrow range of sound frequencies, it may not work on lower frequencies at all.

Finally, since the microphone is outside the headset, it can be more sensitive to rustling winds. So if you want to go jogging with a feedforward noise cancelling headset, you may want to see if it’s windy out. 

Feedback ANC

Feedback active noise cancellation headphones have the microphone inside the ear cup and in front of the speaker. Immediately, we can see that this reverses the feedforward ANC setup. First, it will hear the signal as soon as the listener does. Hence, it can generate anti-noise which it can hear itself. Thus it can self-correct itself.

However, the microphone will hear the outside noise as soon as the listener does. Hence, that can take away from the ANC experience a little. The headset can actually filter out the bass-y sounds that some users so desperately want to enjoy. Yet, even if the noise is coming in at a weird angle, noise processing will always take place the same way.

However, it still can’t deal with high frequency sounds, and thus can’t suppress noise in the 1-2 kHz range. There’s also a risk of awful feedback noise.

Hybrid ANC

Hybrid noise cancellation uses microphones both on the inside and outside of the ear cups. Hence, you get all the benefits of the feedforward and feedback ANC headsets and improvements on their faults as well. Hybrid headsets can correct errors at higher frequencies and adapt to noise and anti-noise.

Now for the downside, since they use twice the microphones, hybrid ANC headsets cost twice as much as well. Also, two microphones can produce twice the white noise, hence higher quality microphones are needed. 

What Else?

Well there’s more to take into account other than ANC in a headset. Does it have multipoint Bluetooth support? Does it have decent sound quality? What about the battery life, and the design? All of that needs to be considered when you decide to purchase a headset for yourself. Price isn’t always the deciding factor.

For example, the Sony WH-1000XM4s are considered the gold standard for ANC over-ear headphones by many. They cost less than both the Bose 700 and the Sennheisser 3 Momentum headphones. Apple’s AirPods Max are much more expensive than either of the previous choices, though the 9 microphones may be the reason.

Either way, if you’re making a choice based on ANC alone, it’s best to do your research before you decide. However, if you’re more of a general listener that wants an all-round solution, you’ll be spoiled for choice. 

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