How Do Noise-Canceling Headphones Work?

Many breakthroughs in audio technology left a mark on how we use equipment such as headphones in the current days. After evolving from dynamic drivers to electrostatic drivers, headphones surprised the world with how real they can sound. In addition, headphones provided immense stereo realism by shifting from a closed-back design to an open-back one.

Following the technical improvement trail, audio manufacturers developed noise-canceling headphones, which work pretty smartly. But first, let’s see precisely how this technology works.

A noise-canceling headphone works in an intelligent and pretty straightforward way. While consisting of a built-in microphone, the headphone captures any external noise happening in the environment. After said audio capture, the headphone plays opposing frequencies that feature the exact representation of the external sounds that the mic recorded. By having two identical signals playing against each other, they’ll cancel one another.

There are two types of noise cancellation: passive and active.

  • Passive: Whenever an outer-ear headphone displays a design that aims for good isolation and leakage control through physical attributes, it’s called passive noise-canceling.
  • Active: An active noise-canceling headphone will attempt to do something against the external noises affecting the mix actively. The headphone will play an identical opposing signal to block sounds from outside the ear cups.

By following a physics rule regarding sound waves, noise-canceling technology can significantly reduce external noise, improving the headphone’s sound stage and frequency response.

Technical Explanation

In layman’s terms, the sound is a pressure wave imprinting the air’s compression and rarefaction. Whenever you record something in the mic, you’re actually getting all this information about the air’s pressure levels, which can shape according to the nearest noises, and transforming it into data.

Whenever you have two recordings of the same sonic content playing simultaneously, you’ll sum two identical signals, improving amplitude levels. If you mirror one of these similar signals against the other, you’ll have that their sum, in this case, will equal zero. You will hear no sound.

The technical term for soundwaves canceling one another is phase cancel, and it can happen purposefully and accidentally. Even during planned circumstances, the ANC doesn’t happen ideally, and although it can be effective, it seldom blocks 100% of external noise.

The built-in microphone won’t capture everything at a crystal-clear quality, for starters. Consequentially, some swift frequencies might evade the ANC’s headphone mic capture and pass the earcups’ seal, reaching the listener’s ear. This often happens during situations where a massive signal appears instantly, such as a car horn.

You’ll want to use ANC headphones during commuting, jogs, travels, and flights to get a better acoustic experience. Models such as the Bose QC 35 II are great in-ear options to use during your daily routine. Using Noise-Canceling headphones for professional work such as mixing or mastering can be detrimental to the hearing experience and hugely affect soundscape.

By using open-back headphones or passive noise-canceling closed-back alternatives, one will benefit from a more neutral sound experience while mixing or mastering.

Story Behind Noise-Canceling

We can assign the first noise-canceling headphones to the American company, Bose, which came up with this technology on its first aviation headsets. While taking a flight, the company’s founder, Amar Bose, noticed how passenger headphones only played music and had a considerable signal leakage, making external interference quite noticeable.

Amar first thought of a noise-canceling solution in the 70s. The audio industry was hugely improving in terms of new technologies, and the market was getting highly competitive, with companies such as JBL, Klipsch, and Polk Audio fighting for the top.

After many years of research and investment, in 1986, Bose had a few prototypes and was beginning to make ends meet on noise-canceling headphones. With the announcement that Dick Rutan and Jeana Reager were planning to navigate the globe on a non-stop flight without refueling, a sound-related issue came to mind for engineers in the mission.

Most engineers feared that during Dick and Jeana’s mission, the duo would hear constant loud noises inside the lightweight cabin, which was lacking seal control. With this exposure to sounds, the pilots would hugely risk their hearing health with this exposure to sounds.

Hearing about the mission, the Bose company reached out to suggest its prototype aviation headset with noise-canceling attributes for the task. Of course, Dick and Jeana took the offer. The headphones worked just as expected, causing some fame about Bose’s aviation headsets to emerge in the piloting community worldwide.

After many outside investments and public hype, Bose’s first noise-canceling went to market in 1989, the Bose Aviation Headset. Then the product got positive reviews for its breakthrough in aviation comfort, resulting in newer models and upgrades in the following years.

In 1995, a new design brought changes to Bose’s aviation headset with the release of the Acoustic Noise Canceling headset series II model. Featuring many improvements in noise-canceling, isolation, and leakage control, the new model got high scores by pilots globally. This more modern version got the Aircraft Owners and Pilots Association award for “Product of the year.”

Bose kept upgrading its headphones and implemented noise-canceling on consumer line models from then on. Different audio companies worldwide began to invest in noise-canceling technology, adapting to the new market scenario. As a result, decades worth of research and development went on, leading to ANC (Active Noise-Canceling) earbuds, monitors, IEMs, gaming headsets, sport earbuds, and more.

Almost every major audio brand has some ANC stuff on its stock as of today. Noise-canceling technology reaches new grounds every year with constant releases from audio giants such as JBL, AKG, Philips, Bose, Sony, Shure, and more.

These are some of the best Noise-Canceling headphones currently in the market:

  • Bose 700 Headphones Wireless
  • Bose QuietComfort 35 II
  • Sony WH-1000XM3 Wireless
  • AKG N700NC Wireless
  • Shure AONIC50

Júlio Roque

Júlio is an audio producer and sound designer. His experience and knowledge of audio and music drive him to write exciting articles related to plugins, hardware, and general audiophile gear.

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