How Do Noise Canceling Headphones Work?

Have you ever wondered how noise-canceling headphones work? Noise-canceling headphones use several different technologies to reduce background noise and other sounds, allowing you to enjoy your music or podcasts without having to crank up the volume and potentially damage your hearing. The technology works by using microphones on each ear cup to pick up surrounding noises and play those noises back out of phase, so they cancel each other out. Learn more about the science behind noise-canceling headphones here!

Passive Noise Cancellation (Or Noise Isolation)

This is a slightly misleading term because passive noise cancellation doesn’t cancel any sound at all; instead, it blocks sound waves from getting into your ears in the first place. This is what makes up- and over-the-ear headphones (and in-ear monitors like Beats and Shure) effective at reducing outside noise: they form a seal around your ear to block incoming sound. If you want to lose yourself in music on a noisy airplane, wearing ANC headphones is an easy way to do so—turn them on. Note that active noise cancellation (explained below) will work even better when paired with passive isolation.

Noise Cancellation with Inverse Audio: The Key To Active Noise Cancellation

The secret to noise-canceling headphones is what audio engineers call inverse audio. You take out what you don’t want using subtractive methods. That’s how sound-canceling headphones create a quiet zone for your ears. When actively canceling unwanted sounds, headphones are at their best when played through the pink or white noise. The reason for that is that pink and white noise contains all frequencies—from low to high—at about equal volumes, which makes them perfect at eliminating any outside noises or voices that might be competing with your music or show.

Active Noise Cancellation Vs. Adaptive Noise Cancellation

The two most popular noise-canceling technologies are active and adaptive. Active noise cancelling headphones feature removable batteries that you recharge via USB. Adaptive noise-canceling technology uses an in-line microphone that measures ambient sound, then plays a sound wave with an opposite phase to neutralize it. Both models will significantly reduce background sounds, but only active noise-canceling headphones work with your device’s power turned off. Most reviews favor active noise canceling technology because of its overall effectiveness and longer battery life. However, neither model has 100 percent accuracy when it comes to nullifying all kinds of noises—from consistent low hums to random loud bursts—and they won’t help you tune out people if their voices are your chief concern.

Common Noise Cancellation Issues

Noise canceling headphones may work well for you, but many things can go wrong. First, you must have compatible equipment. Noise-canceling headphones are designed to be used with specific devices—check your manufacturer’s website to ensure compatibility with your phone or another device. Another issue may be crosstalk—if one headphone is playing music while noise cancellation is activated, it may interfere with sound processing and create an echo effect. This means both earpieces must be working at all times for best results. Finally, keep in mind that these products will not cancel out loud noises if they come from above or below you—but you can block out ambient sounds by wearing your headphones around your neck when not in use.