What is ANC Or Active Noise Cancellation ANC? Why It Is Essential On Earphones And Headphones

Just a few years back, ANC or active noise cancellation was considered a premium feature and was only found on high-end headphones. However, the technology has democratized over the last few years, and the same is now available even on affordable earphones and headphones that just costs around Rs. 3,000 in India.

So, what is ANC? ANC stands for active noise cancellation. In simpler terms, it actively cancels the outside noise in real-time, which will help the users to cut off the external noise. Depending on the product, an ANC-capable headphone or an earphone can partially or completely block the noise cancellation.

An active noise cancellation capable headphone or earphones first process the surrounding sound using built-in microphones. Depending on the type of headphone, it might have two or even four microphones for an improved ANC experience.

As one can expect, expensive and premium earphones/headphones offer better noise cancellation when compared to cheap and inexpensive earphones. Hence, headphones like Sony WH-1000XM4, Apple AirPods Max, and the Bose Noise Cancelling 700 are currently some of the best noise cancellation headphones in the world.

Earlier, the ANC feature was limited to headphones. However, the technology is now available on neckband style and TWS style wireless earphones. Even some of the cheap TWS earphones priced around Rs. 3,000 now support active noise cancellation, although they might not be as effective as the aforementioned headphones.

How Does ANC Work?

An ANC-capable headphone or earphone first listens to the outside noise, which is mostly a low-frequency noise, and cancels it out before it reaches the user's ears. It's like subtracting the positive number with a negative number to create zero. In this case, the external sound is paired with computer-generated sound with reverse polarization.

To optimize ANC, a headphone will usually have at least four microphones, two for each ear. One microphone will be located on the outside, while the other one will be located on the inside. The earphone or headphone processes the sound and creates an anti-sound with an opposite phase (sound wave).

These sounds cancel each other, offering a noise-free environment. Again, this works well when the external sound wave has a constant amplitude. Do note that, all this happens in a fraction of a second, and the headphone will be making constant analysis of the sound to deliver the best possible noise cancellation experience.

One can always play music along with ANC to get an even better noise cancellation experience. When ANC is enabled, the battery will reduce quickly. Modern earphones and headphones now offer features like full active noise cancellation, and transparent mode, which plays the external sound with audio enhancements.

Cheaper headphones that do not support ANC feature noise isolation, which blocks the external sound. However, these headphones do not do as good of a job as ANC headphones when there is low-frequency audio. Hence, an ANC headphone will work best in most cases when it comes to noise cancellation and noise isolation.