Active noise cancellation (ANC) is a standard feature in good wireless headphones and earbuds, and this can significantly improve your listening experience in noisy environments. With ANC turned on, the headphones electronically reduce incoming noise, allowing you to focus on the sounds that matter. When ANC works correctly, it’s an incredible experience. However, before we jump into how ANC headphones work, let’s briefly discuss sound itself.
What is sound, exactly?
Sound is the result of changes in air pressure that cause the eardrums to vibrate. These vibrations travel through bones in the head to reach the auditory cortex, where they are perceived as sound. Loud or bass sounds can be felt outside of the ears and are the result of the displacement of air molecules. Sound waves can be visualized as waveforms, with amplitude representing loudness and wavelength representing pitch.
How noise-canceling headphones work: Anti-noise
Noise-canceling headphones use built-in microphones to detect incoming sound and analyze it to create anti-noise, which neutralizes the noise. The anti-noise wave has the same wavelength as the target sound wave, but its amplitude’s phase is inverted, which cancels out the noise. Ideally, this results in complete silence for the headphone user.
The limits of active noise cancellation
While ANC is great at canceling out consistent, low-frequency noise, irregular, organic background noise is more challenging to cancel in real-time. ANC struggles against unpredictable ambient sounds like other people’s music in a coffee shop. Furthermore, ANC becomes less effective against higher frequency sounds as the physical distance between headphones’ microphones and drivers, and the eardrums become more critical. ANC is also generally more effective in over-ear headphones than in-ear buds due to their better passive noise cancellation.
Behind the ANC curtain
Overall, ANC is a remarkable technology that ensures an immersive, distraction-free listening experience. With this understanding, choose your earbuds or headphones wisely, considering your intended listening environment and desired ANC performance. To learn more about complex technological concepts, you can check our coverage of other techy things like mobile photography’s pixel binning and the Matter smart home standard.