Technology
How do noise-cancelling headphones work?
Noise-cancelling headphones work by listening to the outside noise with tiny microphones, then playing a sound wave that's the exact opposite. The two waves cancel each other out, leaving you with much less background noise.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how noise-cancelling headphones works.
Step by step
- 1Microphones capture the ambient noise around you.
- 2The headphones generate an 'anti-noise' wave — the inverse of that sound.
- 3The two waves collide and cancel (destructive interference).
- 4It works best on steady, low hums (engines, AC), less so on sudden sounds.
Frequently asked questions
- How do noise-cancelling headphones cancel sound?
- They play a wave that's the mirror-opposite of incoming noise, so the two cancel out.
- What is destructive interference?
- When two opposite sound waves overlap and flatten each other, reducing the sound you hear.
- Why don't they cancel all noise?
- Sudden, unpredictable sounds are hard to invert in time, so they work best on steady hums.