With the development of nuanced and more high-quality feature packed headphones, the usage of the word Active noise cancellation has increased, some know how it works, some know that it works, some doesn't even know its existence, today let's see the working, the benefits, and the history behind it.
History
The term ANC have been more and more widespread over a decade or two, but this name, and this concept dates back to 44 years ago in 1978. Yes, that happened when Dr. Amar Bose took a flight, from Zurich to Boston, while he was on the flight listening to headphones, the music from the earphones got completely drowned out by the noise of the plane.
Frustrated, he decided to derive a solution to it, his idea was to make "earphones that listen" This was harder to do than to say. It took him 10 more years to actually make a working prototype in 1986. This soon became a product worn by airline pilots, military officers and later this was also given to first, and business class passengers abroad American airlines.
The name of the creator (Amar Bose) might sound familiar, he is the one who founded Bose sounds, which later became synonymous for their audio products and noise cancellation technologies.
Headphones with this technology soon came to regular customers once the costs came down eventually.
Pre-requisite knowledge
When you turn on these headphones, while you are listening to music, the headphones will constantly hear you. To know more about it you should know how noise/sound works. If you see, sound is a form of a wave, and the sound wave for every word, every letter you say is different. If you combine any two sound waves, the overall volume of the sound gets louder, this is called as constructive interference of sound, this is the same reason why you hear the sounds of the people talking louder as more people join a crowded place. This can also be used negatively, I.e., making the sound lower by interference. This is a similar concept to constructive interference but it is the opposite of it. This is called Destructive interference and this is what used in Noise cancelling earphones.
Working
The earphones as I have already mentioned has microphones and are always listening to everything outside. As we know sound travels as waves and each wave has its own peaks and valleys.
When these earphones detect sound, they produce their own sound and plays it alongside your song. This soundwave looks like the mirror image of the actual noise. Both the waves cancel each other out and creates divine silence. The below picture explains this better.
Sound-leak
If you are an Active Noise Cancelling headphone user, then you might have noticed this doesn't cancel out every single noise. You may still hear people if they are talking loudly, or if vehicles are moving fast. This noise leakage is because, this technology works best with consistent and predictable noise
When there is too much variation in the soundwave received, working with a negative soundwave to cancel the noise becomes tricky and harder for the computer inside to work with. Hence, the sound leak. Another reason is that, if the noise is milder than what the microphone can hear, it lets in the noise and does not cancel it out. Hence you may notice slight noise leak. This depends on the ability of the mic to hear the noise accurately and the ability of the processor to process a negative frequency at an instant.
Today, this technology has helped a lot to many, it helped them get through busy ares and commute with ease, this is how the technology works, if u have learnt something new, comment down below, i have got more articles regarding tech in my website, check those too and follow for more updates, rate us for encouragement! This is Raghunath Balaji from Tech passion, signing off.