Noise Cancelling Headphones - The basic principles of How They Block Unwanted Noise1131386

De GEATI - Grupo de Estudos Avançados em TI
Ir para: navegação, pesquisa

There are basically two types of headphones created to reduce background noise. Passive noise cancelling headphones and Mute Background Noise. The passive type muffles extraneous sounds while the active ones electronically decrease external noise.


Passive noise cancelling headsets use what is called circum-aural sound dampening design. They're shaped like a single cup, which surrounds the ear. The rim of the cup consists of a high-density foam and sound wave dampening material. This creates a seal that blocks as much as 20 dB of noise.


The active noise cancellation headphones provide an additional 20dB of noise reduction compared to passive type. It employs the identical technology (circum-aural sound dampening design) because the passive headphones but in addition incorporates phase cancellation. Here is the key feature of active noise cancelling headphones. A microphone is positioned inside the headphone that picks up external noise how the aural cushions with the passive headphones can't block out. The phase cancelling technology is able to analyze the intensity and frequency with the pitch, also known as the loudness and pitch from the noise. The circuitry then creates a perfect replica from the noise and throws it 180 degrees out-of-phase. This, for those intents and purposes, eliminates the sound.

The headphone speaker then plays this "non-sound" in addition to whatever it is that you're listening to. This artificial noise will be the exact opposite with the extraneous noise which makes it past the ear cushions. Then they cancel each other out as a result of 180-degree phase reversal. As a result the external noise is reduced significantly, letting you enjoy your audio having a dramatic decline in background noise.

These kinds of headphones are fantastic for airplanes or any place where there quite a bit of external noise. On airplanes, as an example, this type of noise reduction while using the headphones will dramatically reduce fatigue.

Another distinction between the two would be that the active type needs a power source, usually a battery.

Noise cancelling headphones are generally larger and heavier that regular headsets or earphones. They could, however, be more comfortable when worn for very long periods of time because of the large cushions that impose less pressure on the ears.