eli5 Noise cancelling headphones are magical but how does the technology work and does it drain the battery?

Question

eli5 Noise cancelling headphones are magical but how does the technology work and does it drain the battery?

In: 341

Answer 1

It works by having a little microphone right next to the speaker listening for the outside noise that you want to cancel, then playing the inverse of that signal into the speaker, such that the two sound waves should cancel each other out. It can drain the battery more quickly than without since it needs to be doing active processing of the microphone signal to do this.