Engadget Explains the Benefits and Drawbacks of Noise-Cancelling Headphones

Engadget explains that ANC is based on physics. The technology has existed for decades but has only recently become popular in consumer headphones and earbuds. Microphones built into the earphones continuously listen to outside sounds, including traffic, conversations and crying babies. Because sound is a wave created by vibration, two opposing waves can cancel each other out in a process called destructive interference. ANC captures the audio from the microphones, analyzes it and plays an inverted signal, so the original and inverted waves cancel each other and block most outside sound.

The system needs a powerful chip that can perform calculations in milliseconds, since any delay can ruin the experience, Engadget says. That requirement helps explain why ANC headphones and earbuds tend to cost more than models that rely only on passive noise cancellation. Passive cancellation depends solely on physical isolation, either from earcups around the ears or earbuds inside the ears.

According to Engadget, the advantages of ANC are easy to see. It removes annoying sounds, making long plane trips more bearable and helping users hear more detail in songs or movies without distractions. Because listeners do not have to overcome outside noise, they can keep the volume lower and reduce the risk of hearing damage. The feature also improves phone calls by helping the user hear the other party more clearly. Even when no music or video is playing, ANC can provide silence for focus, which may help people who react negatively to external stimuli. Some people even wear ANC earbuds to sleep.

Drawbacks remain. Engadget says ANC works best with low, steady noise such as the hum of a plane or air conditioner, and is less effective against sudden higher noises like horns honking or people shouting. Depending on the exact headphones, ANC can sometimes reduce audio quality, and some people say their ears hurt when using the feature. Isolating too much from the world can also become a problem. Hearing the sound of cars while crossing the street or riding a bike is crucial, and talking to nearby people with noise cancellation turned on is difficult. Some studies suggest that noise cancellation may affect how the brain filters out background noise, Engadget reports.

Many headphones offer a hybrid mode, such as Transparency Mode on AirPods, to balance ANC with sound from the outside world, according to Engadget. Battery life is another consideration. Noise cancellation drains the battery much faster, and turning the feature off can help earbuds last longer throughout the day. Many people are still willing to pay that price for silence, Engadget says.