Eli5 How exactly does Noise cancellation work? That too in such small airbuds

Question

Eli5 How exactly does Noise cancellation work? That too in such small airbuds

In: 528

Answer 1

Sound travels in waves.

The waves have peaks (high spots) and valleys (low spots). Anytime two sound waves collide, if a peak hits a peak or a valley hits a valley, they grow and make the sound more intense.

On the flip side, if a peak hits a valley they cancel each other out, the bigger one still pulls through but with reduced intensity. Or, if a peak hits a valley of the same size, they perfectly cancel out with zero sound. That’s where the headphones come in.

Noise cancelling headphones study the background noise to find out where the peaks and valleys are.

Next, the headphones create their own sound wave that has valleys where the ambient sound has peaks and vice versa. This means the created sound meets the background noise and everything is cancelled (or at the very least dramatically reduced).