eli5 how does noise canceling/transparent mode work on earbuds?
In: Technology
Imagine you’re wearing special headphones that can make noisy sounds around you disappear. These headphones have tiny microphones that listen to the noises, like people talking or cars honking. Then, they make special sound waves that are the opposite of those noises, kind of like whispering the opposite words. When these opposite sounds mix with the noisy sounds, they cancel each other out, making it quiet for you.
Now, transparent mode is like having super ears. You can still hear the important things, like your mum calling you or a car approaching, while you’re wearing these headphones. It’s like having a secret switch that lets you listen to both your music and the world around you at the same time.
Sound is a wave, every wave has a certain wavelength and what’s called phase which is basically where on the wave you are. Noise cancellation works by creating another wave that cancels out the original sound, this new wave has the same wavelength but a different phase. We get rid of noise by adding noise, weirdly
Sound is a wave.
You can take 2 waves and “add” them together. If the 2 waves are exact opposites of one another then when added together they will equal nothing. It’s like taking 95+(-95)=0.
Noise canceling devices have a microphone that listens to the sound from outside, it then generates an “anti” wave that exactly matches the outside sound and plays that anti wave through the speakers.
So what your ears hear is the sound from outside, plus the antirave that equals zero. They literally generate a new sound that cancels out the external sound.
Sound is is when air vibrates. The speakers inside earbuds vibrate to move the air, to make sound.
You can still hear when wearing earbuds because the earbuds are moved back and forth by the air, because of sounds around you. Again air between the earbud and your eardrum moves back and forth because of the earbud: sound. Microphones on the earbuds pick up how the air moves back and forth around you, and make the speaker move in the opposite direction. If the movement in the opposite direction is just right, the air in your ears doesn’t move, and you don’t hear anything.
To make the earbuds “transparent” we can make it move the speaker in the *same* direction, so that your eardrum is pushed and pulled *harder* by sounds around you, because the earbud is “helping”.
TL;DR: Air pull ear one way, headphone push other way, like tug of war perfectly matched. No movement, no sound.
Sound is a wave. If you take two waves and overlap them, they add together. If you have two waves where a peak of one lines up with the troughs of another, they will perfectly cancel out and act like there’s no wave there at all.
The headphones have a microphone on the outside, recording the ambient noise, and then play the exact inverse of that sound on the headphones, what hits your ears is no sound at all.
It’s not perfect, so some sound does get through, but it does a very good job.
You can also still play music by just adding the sound waves of the music to the inverse of the ambient noise, and what hits your ear is just the music, and no ambient noise.
Please use the search function (as you have to in order to post), this has been asked countless times.
Brief answers:
ANC: Microphones listen to the outside and the speakers invert it to cancel.
Transparency: Microphones listen to the outside and the speakers play it.
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