Credits: Social Media
How noise-cancelling headphones actually block out sound will blow your mind
A man has had his mind blown after discovering how noise-cancelling headphones actually work – and you will be gobsmacked too.
He took to TikTok to explain the phenomenon, and people were shocked to find out it’s not the ear cushions that muffle the sound.
How noise-cancelling headphones actually work
It all comes down to physics. Sound waves are cancelled out when an opposite sound wave is played at the same time, resulting in complete silence, LibreTexts explains.
“Noise-cancelling headphones have a little microphone on the outside that records the ambient noise around you and plays it back to you at the same time as you’re hearing the noise from outside the headphones,” the TikTok user said.
However, it plays it with a polarity inverse, which means the sound waves are flipped upside down. This cancels out the sound and you hear nothing.
“So what that means is noise cancelling headphones are actually playing the sound that you don’t want to hear back to you but just cancelling it out,” he continued. “That’s really cool. You’re hearing it twice but it’s cancelled out.”
“Noise-cancelling audio devices use a built-in microphone to analyse the ambient sound waves around you and generate the opposite sound waves to reduce surrounding sound,” Sony explains.
So, why can you still hear some noise when you’re wearing noise-cancelling headphones? Well, noise-cancelling technology cannot completely isolate sound due to the air trapped between your audio device and the eardrum.
When people speak, there are also sudden changes in pitch which occur very frequently. This makes is difficult for any noise-cancelling device to process these differences, meaning you hear some noises while others are cancelled out.
‘I thought it just blocked out the noise’
If you thought the big cushions over your ears just blocked out the sound, you’re not alone. Loads of people didn’t realise the headphones actually record and play sound back to you.
One person commented: “I genuinely thought it just blocked out the outside noise with& like& size.”
“Had no idea thats how they worked. Thats amazing,” said another.
A third person added: “I get it but I also dont get it, this just blew my mind a little.”
You learn something new every day!
