Noise Cancelling Headphones - The fundamentals of How They Block Unwanted Noise2138969
You can find basically 2 kinds of headphones developed to reduce background noise. Passive noise cancelling headphones and Noise Cancelling Software. The passive type muffles extraneous sounds while the active ones electronically decrease external noise.
Passive noise cancelling headsets use what is known as circum-aural sound dampening design. They are shaped like a cup, which surrounds the ear. The rim of the cup is constructed of a high-density foam and sound wave dampening material. This produces a seal that blocks up to 20 dB of noise.
The active noise cancellation headphones provide an additional 20dB of noise reduction than the passive type. It employs exactly the same technology (circum-aural sound dampening design) since the passive headphones but additionally incorporates phase cancellation. This is the key feature of active noise cancelling headphones. A microphone is placed inside the headphone that picks up external noise the aural cushions from the passive headphones can't block out. The phase cancelling technologies are able to analyze the intensity and frequency of the pitch, also called the loudness and pitch from the noise. The circuitry then creates a perfect replica with 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" together with whatever it is that you will be listening to. This artificial noise will be the exact opposite from the extraneous noise which makes it past the ear cushions. They cancel one another out due to the 180-degree phase reversal. As a result the external noise is reduced significantly, letting you enjoy your audio using a dramatic reduction in background noise.
These kind of headphones are fantastic for airplanes or anywhere where there is a lot of external noise. On airplanes, for example, this type of noise reduction while using headphones will dramatically reduce fatigue.
Another distinction between the two would be that the active type requires a power source, often a battery.
Noise cancelling headphones tend to be larger and heavier that regular headsets or earphones. They can, however, become more comfortable when worn for long periods of time due to the large cushions that impose less pressure about the ears.