Noise Cancelling Headphones - The Basics of How They Block Unwanted Noise7519150

There are basically 2 kinds of headphones designed to reduce background noise. Passive noise cancelling headphones and background noise reduction. The passive type muffles extraneous sounds while the active ones electronically decrease external noise.

Passive-

Passive noise cancelling headsets use what is known circum-aural sound dampening design. They may be shaped like just one cup, which surrounds the ear. The rim of the cup is made of a high-density foam and sound wave dampening material. This results in 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 exactly the same technology (circum-aural sound dampening design) since 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 that the aural cushions with the passive headphones can't block out. The phase cancelling technologies are able to analyze the intensity and frequency of the pitch, also known as the loudness and pitch of 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. They cancel one another out because of the 180-degree phase reversal. Consequently the external noise is reduced significantly, allowing you to enjoy your audio with a dramatic reduction in background noise.

These types of headphones are perfect for airplanes or anyplace where there is a lot of external noise. On airplanes, as an example, this type of noise reduction while using headphones will dramatically reduce fatigue.

Another difference between the two is that the active type takes a power source, usually a battery.

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