In the past, you only had the option of turning up the volume of the music in order to block out disturbing background noise when enjoying music via headphones. However, this can lead to permanent damage to the ears. Those days are over with Active Noise Canceling (ANC).
Active noise canceling can be translated as “active noise suppression”. As opposed to passive cancellation, the technology identifies ambient noise and actively reduces it – hence the name. Microphones pick up the ambient noise. The microchip analyzes these sounds and emits sound waves that eliminate the surrounding noise.
Noise reduction through anti-noise
The physical principle behind it: When two polarized sound waves meet, they almost cancel each other out. By polarized it is meant that the phases of the sound waves are shifted by 180 degrees. Assuming the microphones in the headphones pick up the sound wave from a jackhammer, the chip calculates the exact anti-noise. In the best case, the opposing sound wave can compensate for the outer sound wave. The result: silence.
The fact that ambient noise is not eliminated 100 percent is because the microphones constantly pass on a number of noises to the microchip, which constantly calculates which counter-noise it has to output. Despite several thousand calculations per second, the speed is not sufficient to eliminate all background noise – after all, sound travels at 340 meters per second.
In order for active noise canceling to work as optimally as possible, passive noise reduction is important. For this reason, the technology works particularly well with closed over-ear headphones and in-ear headphones. Over-ear headphones enclose the ears and can already dampen outside noise. The same applies to in-ear headphones with silicone attachments that seal the auditory canal.
Adaptive ANC and transparency mode
Various types of active noise canceling now exist. With Adaptive ANC, the headphones automatically adapt to the noise environment. On the other hand, with the adjustable ANC, the user can decide for himself the level of noise cancellation.
If you still want to get a glimpse of the surroundings, use the transparency mode. It lets the ambient noise through without having to turn off the music or take off the headphones.
Some newer models of headphones have a transparency mode that automatically reduces the volume of loud noises. For example, the telephone or doorbell can be heard clearly while the neighbor’s lawnmower is turned on quietly.