Noise Cancelling Headphones - The basic principles of How They Block Unwanted Noise3561148

You will find basically 2 kinds of headphones developed to reduce background noise. Passive noise cancelling headphones and real time noise reduction. The passive type muffles extraneous sounds as the active ones electronically decrease external noise.

Passive-

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 made of a high-density foam and sound wave dampening material. This produces a seal that blocks up to 20 dB of noise.

Active-

The active noise cancellation headphones produce an additional 20dB of noise reduction than the passive type. It employs the same technology (circum-aural sound dampening design) as the passive headphones but additionally incorporates phase cancellation. Here is the key feature of active noise cancelling headphones. A microphone is placed inside the headphone that accumulates external noise the aural cushions of the passive headphones cannot block out. The phase cancelling technologies are able to analyze the intensity and frequency with the pitch, also known as the loudness and pitch of the noise. The circuitry then creates an exact replica of the noise and throws it 180 degrees out-of-phase. This, for many intents and purposes, eliminates the sound.

The headphone speaker then plays this "non-sound" in addition to whatever it is that you are listening to. This artificial noise may be the exact opposite from the extraneous noise that means it is past the ear cushions. Then they cancel the other person out due to the 180-degree phase reversal. Consequently the external noise is reduced significantly, allowing you to enjoy your audio with a dramatic decline in background noise.

These kind of headphones are perfect for airplanes or anyplace where there is a lot of external noise. On airplanes, for example, this type of noise reduction with all the headphones will dramatically reduce fatigue.

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

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