Do you love to listen to music? We do! Of course, sometimes your friends and family members might not be interested in listening to the same tunes you enjoy. So what do you do? Put on a pair of headphones and retreat into your own private musical world!
Headphones deliver the music you love straight to your ears without broadcasting it to all those around you. Unfortunately, they don't always block out the rest of the sounds floating around in the air. If you've ever tried to listen to music in a car, on a bus, or in the midst of a crowded airplane, you know that it can be difficult to block out ambient noise and concentrate on your tunes.
Thanks to modern technology, however, you can now buy headphones that block out the noise and let you enjoy nothing but the music you want to hear. Are they magic? Nope! They're scientific, and they're called noise-canceling headphones.
At first, noise-canceling headphones might sound like a contradiction. After all, aren't they supposed to produce the sounds you want to hear? How can they do that while also silencing the noise around you?
Most noise-canceling headphones rely on two types of noise reduction technology. The first is passive noise control, which simply uses design elements to help block unwanted noise. For example, the shape of headphones and the material they're made from can physically block certain sound waves from reaching your ears.
While passive noise control works to an extent, it was not good enough for Bose Corporation founder Amar Bose. On a trans-Atlantic flight in 1978, he realized that noisy passengers and loud jet engines were disrupting his enjoyment of the music he was trying to listen to. He began to think about how he could use the physics of sound to create a system that would result in a better listening experience.
A decade later, active noise control (ANC) was introduced by Bose Corporation. ANC works by using destructive interference to cancel out unwanted noise. Let's take a closer look at how that process works.
Noise-canceling headphones feature microphones that pick up the frequencies of ambient noise. A digital signal processor inside the headphones then calculates exactly what type of sound waves would cancel out the unwanted sounds.
Given the laws of physics that apply to sound waves, sound waves with frequencies exactly 180 degrees out of phase with each other will cancel each other out, resulting in silence. The digital signal processor in noise-canceling headphones produces the necessary sound waves and amplifies them through the headphones, thereby using destructive interference to cancel out the ambient noise.Noise-canceling headphones are not perfect. They're usually most effective for ambient noise at low frequencies. Experts note, however, that they can effectively reduce overall noise by as much as 80 decibels, which should be enough to reduce irritating interference from loud jet engines on an average airplane flight.