Noise-Cancelling Headphones: How Do They Actually Work?

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Noise-cancellation – a common enough term. We’ve all heard about it, and it seems like a perfect idea. But how do noise-cancellation headphones actually work? They don’t just merely block the sound – that’s what regular headphones do. So how do they do it?

It all comes down to sound waves. The headphones contain microphones that capture the sound waves as they reach your ear, and then electric circuitry generates an “antinoise” signal. This signal is an inverted copy of the original sound wave, which then travel together into your ear. The waves interfere with each other, called destructive interference, and no sound reaches your ear.

So why bother? It seems a bit excessive, doesn’t it? Regular headphones do a pretty good job of blocking the sound. Even if your surroundings are loud, you can just turn your headphones’ volume up, right? Well, yes, of course you can. But when you’re sitting on an airplane, trying to sleep next to the roaring engines, and you have a choice between turning up the volume – greatly – and cancelling the noise entirely, what would you choose?

Also, if you think about it, you’re doing yourself a favor. Every time you turn up your headphones to cover up the outside noise, you damage your ears just a bit more. You know how when you walk out of a concert and your ears are ringing? That’s damage to your eardrums. So, instead of turning up the volume, you should cancel out the ambient noise, and save your hearing. You’ll thank yourself later in life.

Personally, I have no need for noise-cancelling headphones. I’m not constantly around loud noises, like in the city, so normal headphones are enough. But then again, I live in a small town. Perhaps someone in San Francisco, or New York, or Los Angeles would find the occasion to use them much more than I would. It all depends on what you’re looking for.

Another alternative is the happy medium – noise-reducing headphones, which still block a great amount of ambient noise. They don’t require batteries, are lighter, and, of course, are much less expensive, while retaining very good quality sound. While the noise-cancelling headphones and the regular headphones have their own niches, the noise-reducing headphones are perfect for any occasion.

Then again, next time I’m on an airplane, I think I’ll be yearning for the noise-cancelling earphones all the same.