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 a lot of adults at the pool. Some of them are misbeahving by running clock wise around the pool. The lifeguard got annoyed and send out other adults that run counter clockwise. These adults smash into each others and stop being obnoxious.

Edit: so noise cancelling headphone detects those obnoxious adults, their locations and their behaviors. Then the headphone sends to these location exactly opposite adults and let them smash into each other and cancel each other out.

Edit 2: we can get a bit more technical (eli6 maybe?). The headphone detects the obnoxious adults by running the Fast Fourier Transform algorithm. The algo tells the headphone two things about the obnoxious adults: 1. the adult size (amplitude) and 2. its speed + direction around the pool (phase). The headphone produces the opposite adults with these characteristics: 1. same size (same amplitude) 2. same speed but move in a different direction(antiphase or phase-shifted by 180 degree ie clockwise vs counter clockwise). When the obnoxious adults and the opposite adults smash into each other (destructive interference), they both get knocked the F*** out.