Noise cancelling headphones are amazing as they eliminate the
painful noise generated by manmade machinery such as air planes, trains and
noises from vehicles etc. Noise is sound wave which does not make sense to
human mind and human mind refuse the sound. This effect is perfectly personal.
In order to reduce the prolong effects from sound waves generated by machinery.
In order to reduce the noise, two types of noise cancelling
techniques are used
1. passive noise cancelling
2. active noise cancelling
In passive noise cancelling technique a
large thick cushion seals each ear to prevent entering sound waves into ear canal.
Ear plugs, Ear muffs are some examples for passive noise cancelling.
Often the generated noise from the manmade machinery is less than 1000Hz and
these types of low frequencies cannot be eliminated by a thick layer of
cushion. The most promising active noise cancelling comes into the role to
provide must better noise cancelling.
In active noise cancelling, microphones pick the background noise
and an inverted wave was generated to cancel out the noise. This technology is not
cheap. These types of devices can cost up to 300-400$s while passive noise
cancelling devices will cost around 30-40$s.
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