Headphones employ multiple types of noise-canceling technology, with the most common being active noise cancellation (ANC). However, some headphones use hybrid or adaptive noise cancellation, and all headphones use a degree of passive noise cancellation.
Active noise cancellation uses microphones on the inside of your ear cups to detect external noise and produce an equal but opposite sound wave to cancel the extraneous noise inside your ear cups. Headphones with only internal mics have less effective noise canceling, but the sound quality tends to remain untouched by the sounds produced by the microphones.
Hybrid noise cancellation is a type of ANC that uses microphones inside and outside your ear cups to listen for a greater frequency of external noise. The additional external microphones make the noise-canceling properties stronger, but sometimes the sound quality is compromised.
Adaptive noise cancellation works similarly to passive and active noise cancellation but uses computer algorithms to assess the noise in your environment. If your headphones with adaptive noise cancellation detect you’ve entered a noisier environment, they will increase the noise cancellation.
Passive noise cancellation, sometimes called noise isolation, refers to how well headphones naturally block ambient by solely covering your ears. There is no technology involved with this kind of noise reduction. Closed-back headphones with a snug fit will have better passive noise cancellation, while open-back and loose-fitting headphones will allow more ambient noise to reach your ears.
