Noise cancelling headphones are built to destroy outside sound, and they do it really well. ANC, also known as active noise cancelling, is an essential feature for anyone who wants to focus on work in a noisy office, listen to music without distraction on a plane or train ride, or stay in the zone during a workout. But ANC isn’t a simple feature that all headsets have – the best headphones for ANC offer a range of different features and techniques to achieve superior performance.
A headset’s ANC technology relies on microphones to pick up unwanted noise, like the hum of your air conditioning or people chatting nearby, then neutralizes it by generating opposite, phase-inverted soundwaves that cancel each other out. A speaker inside the ear cup plays these neutralizing waves back, effectively drowning out the other sounds around you.
In our tests, ANC can reduce ambient noise by 30dB or more, though we’ve also found it can affect the quality of your audio playback. ANC waves can cause a high-pitched hiss in your ears that’s hard to hear while wearing the headset, but it’s a small price to pay for the freedom to listen to music or podcasts with complete isolation from the outside world.
Another downside to ANC is that it can make it harder for you to hear your surroundings, which could be dangerous in an emergency situation such as a car honking its horn outside your coffee shop. But that’s why many ANC headsets have an ambient/transparency mode to repurpose the mics and let you hear your surroundings while keeping the benefits of ANC in place.
As headset technology advances, manufacturers are finding new ways to enhance ANC performance. Some earbuds have adaptive EQ, which uses an inward-facing microphone to measure the sound of your ear in various situations and automatically makes EQ adjustments to reduce external sound. It’s a feature that’s available on some of our top picks for wireless earbuds, such as the Bose QuietComfort 2 Wireless Earbuds and the Life Q30.
Other models use hybrid ANC, which combines feedforward and feedback setups. The microphones on a pair of ANC headphones are placed inside the ear cups and in front of the speakers, which gives them the ability to hear what you hear (and correct mistakes if they occur). This means that hybrid ANC is less sensitive to changes in how the user wears their headset and can suppress a wider range of frequencies.
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Finally, some headsets have a custom-built ANC that’s tuned specifically for the ear shape and size of each user. This is how the latest versions of the Bose QC X and QC II headphones deliver such excellent ANC, as well as the superb fit and seal you’ll get with these premium earbuds.