Noise cancelling is a technology that has been around for decades, but it’s only recently become popular in the headphone world. It works by using microphones to detect ambient sound and then playing back an opposite waveform through speakers or earbuds. This cancels out the unwanted sounds, leaving you with just your music.
The most common type of noise cancellation uses physical barriers like foam or plastic to block out outside noises. The problem with this approach is that it can’t completely eliminate all background noise, especially if there are gaps between the two audio signals. That’s where digital noise cancellation comes into play. Digital noise cancellation relies on algorithms to analyze incoming audio waves and determine which frequencies need to be canceled out. Then it plays back an opposing signal at those same frequencies.
Digital noise cancellation isn’t new; it was first introduced in the 1980s as part of cassette players. But it wasn’t until the mid 2000s when Sony released its first pair of noise canceling headphones that it became more widely adopted. Since then, many other companies have followed suit, including Bose, Sennheiser, and Master & Dynamic.
What does ‘noise’ mean?
Before we dive into how noise canceling works, let’s talk about what exactly constitutes “noise.” Noise can come from any number of sources: traffic, construction, air conditioning units, fans, etc. In fact, one study found that nearly half of Americans experience some form of daily noise pollution. When it comes to headphones, noise refers to anything that interferes with your listening experience. For example, wind noise is caused by vibrations from passing cars, while engine noise is created by the movement of pistons inside a car’s engine. These types of noises are usually very noticeable because they’re loud enough to carry over long distances.
How do noise-canceling headphones work?
Now that we know what noise means, let’s take a closer look at how noise-canceling headphones work. Most noise-canceling headphones use either active or passive noise cancellation. Active noise cancellation requires a battery to power the electronics needed to perform the analysis. Passive noise cancellation, meanwhile, relies on the headphones themselves to create a barrier against external sounds.
Active noise cancellation
Active noise cancellation involves a microphone that detects ambient sound and sends a corresponding signal to the headphones. The headphones then play back an opposing signal, creating a wall of silence around you.
There are three main components involved in active noise cancellation:
Microphone : A small microphone picks up ambient sound and sends it to the processor.
Processor : The processor analyzes the incoming soundwaves and determines which frequencies need to be canceled out. It then creates an opposing signal and sends it to the speaker(s) or earbud(s).
Speaker: The speaker or earbud play back the opposing signal, canceling out the unwanted sounds.
Passive noise cancellation
In contrast to active noise cancellation, passive noise cancellation relies solely on the headphones themselves to block out ambient sounds. There are no batteries or processors required. All you need is a good set of headphones.
The basic principle behind passive noise cancellation is similar to the way a windshield wiper works. Windshield wipers move back and forth across the glass to clear away water droplets. Similarly, passive noise cancellation moves back and forth across your ears to block out unwanted sounds. The difference is that instead of moving back and forth, passive noise cancellation uses the shape of the headphone