You may have used it or maybe seen it advertised, but have you ever wondered how noise cancellation works? Most of the current headphones come with this feature inbuilt. You just flip a switch and all the sound in the environment disappears. Cool right? Let’s find out the physics behind this.

From Physics, we know that sound travels in waves called sound waves. Whether its birds singing in the morning, the chimes of your morning alarm or the sound of ocean waves splashing along the beach(which i find quite relaxing), they are all sound waves. These sound waves are transferred through an elastic medium like air into our ears, vibrating the diagram in the ear enabling us to interpret the sound.

Devices that catch sound waves(microphones) and those that replicate sound waves(speakers) are common and have been around for a while. Headphones are commonly known for doing the two functions of recording and playing sound, but how do they achieve the third feature of canceling noise?

The physics behind it is quite simple. Knowing that sound travels in waves and we can record and replicate the sound, what will happen if we invert the wave? Waves of equal amplitude and opposite phase cancel out. If we receive a sound wave from the environment, invert it and play it back immediately, the two will cancel out their vibrations resulting in no waves hence no sound.

And there you have it. The headphones simply record the noise from outside, invert it and play it back along with the music you are listening to. Some do it very well, while others not so as good. It depends with the quality of headphones that you purchase and the engineering that has gone into perfecting this concept in the product.

Where would this be used? This technology is mostly used in aviation. The headphones worn by cabin crew to help reduce noise in the cabin area and make communication easier. It is also used by patients suffering from insomnia to help them sleep better in a noisy environment. The technology is also used by sound engineers to eliminate a particular sound wave from audio. I have once used it to remove vocals from stereo music and only leave instrumentals.

For people who prefer soft music, you can now enjoy your cool music even in a noisy place without turning the volume too loud. Would you find the noise cancellation feature helpful to you as a basic consumer? Let us know in the comments below.