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

There are two forms of noise cancellation. Active and passive. Passive essentially means just blocking sounds from getting by such as how over the ear hearing protection works. Active uses electronics and math. The active method is fairly simple to explain though may be more ELI 17 due to geometry and sinusoidal waves. A microphone picks up the ambient noise, and reproduces it in the speaker 180° out of phase which in turn nulls the sum of the noise’s amplitude. The out of phase thing, just means there is an ever so slight delay (which is dependent on the frequency).