How Do Noise-canceling Headphones Work?

If you're a commuter or want to listen to music anywhere but in a soundproofed room, there's no better option than wearing noise-canceling headphones. Many people think they need to pay more for better sound quality, but that's probably only half right: You also need to protect against noise that could damage or overwhelm your music before it reaches your ears. A lot of companies have tried Active Noise Cancellation (ANC) headphones, and some of them do it so well that it's one of the main selling points of their wireless headphones. But how do noise-canceling headphones work? Why is it so cool?

To understand how to remove noise, first, understand what it is. The sound you hear is really just the compression and decompression of particles flowing through a medium - for our purposes, we're talking about air. Think of sound as ripples moving through the air. These moving particles cause very slightly, rapid changes in air pressure. We call these changes in air pressure amplitudes measured. Your ears and brain detect and decipher these changes in pressure as sounds. If you plot the amplitude over time, you will end up with a waveform like the one shown above. The larger the amplitude, the louder the sound. The faster the change, the higher the pitch.

Sound can be wanted or unwanted, it can be pleasant or unpleasant. Noise is generally defined as unwanted, unpleasant, or very loud sounds.

Your headphones cancel out ambient noise by using a trick called "phase inversion" to create "anti-noise". The concept is simple, but getting it right is tricky.

If you're taking two identical waves and aligning them with each other, matching the crests and troughs, the two waves are called "in phase" and when added together create a more significant wave (bigger sound). But what happens if you delay one of the waves by exactly one-half wavelength, matching the trough to the peak of the other wave?

The two waves are then called "out of phase" and subtracted from each other because the positive pressure of one wave acts on the negative pressure of the other, and vice versa. Think of it as adding and subtracting one, leaving you with zero. Is this the basic physics behind noise cancellation?

To create noise immunity, the headphones must constantly monitor and sample ambient noise using tiny built-in microphones. They "listen" to the ambient noise around you, and the onboard electronics pick it up. In addition to your music, the headphones produce the exact opposite of the sound waves to cancel them out, so all you should hear is the music coming from the headphones, not anything going on outside.

Of course, this is all theoretical. In practice, noise reduction is difficult and far from perfect. Compared to sudden, random sounds, such as people talking, headphones are easier to identify and eliminate persistent noises like the muffled hum of jet engines on planes.

While the physics remains the same, some companies do a better job of active noise cancellation than others. But now that you know how it works, you can choose which pair is right for you. If you want to buy noise-canceling headphones, please contact us.

JUNYE is a professional custom earphone manufacturer. We provide one-stop service, design-development-production, and shipping. With more than 400 employees, 60000㎡ factories, specializing in OEM/ODM. We have our own mold center and the whole industry chain: hardware, injection molding, wire, cushion, assembly, and packaging. Has 8 production lines, including two professional TWS lines. We manufacture each part in-house to ensure quality and on-time delivery.