noise cancelling headphones are the industry standard and should be used when trying to work in a loud and noisy environment, such as inside an airplane or other aircraft, beside launching aircraft, operating machinery, and working in a concert setting. Noise cancelling headphones are the norm in these types of environments because workers need to protect their ears from intense, high-volume sounds that might damage the eardrum or otherwise impair workers’ auditory senses.
Noise cancelling headphones work by using devices that promote active noise control. The active noise control cancels out interfering, ambient sounds like the droning sound of a large machine or the noisy hum of an airplane. Active noise control involves circuitry and gadgets such as small microphones placed inside the noise cancelling headphones. The signals these microphones emit are used by special electronics inside the headphones to produce an anti-noise signal, which are then produced by the speaker driver inside the headphones. When the opposing signals meet, destructive interference is caused thereby cancelling the unwanted ambient noise as it is heard inside the noise cancelling headphone.
Noise cancellation technology is easy to manufacture. Because of this kind of technology, it is possible for people to enjoy sound and music inside the headphones even with little volume. The user can also use noise cancelling headphones to simply shut out sound when he/she wants to sleep. However, the kind of noise cancelling technology present is only enough to shut out the low frequency sounds. Higher frequency noise can enter the headset inside and bypass the active noise control of the device, disturbing the user as a result. 
In order to block out high frequencies, conventional sound blocking technology is used, such as circumaural headphone designs that cover the ear completely. Vibration dampening foam is used to further add to the effect.
Higher frequencies cannot be completely blocked, however. One needs to place the active noise control emitter and circuitry adjacent to the eardrum to truly shut out higher noise frequencies. Of course, this is not technically possible, so noise cancelling headphones are built in the traditional way. Doing this won’t require the headset to have complicated circuitry and electronic design.
Despite the obvious benefits of noise cancelling headphones, they still have limitations. For one, because they are not truly capable of cancelling higher frequency noises, they are ineffective in blocking out speech and audio signals that rapidly fluctuate in frequencies. Still, noise cancelling headphones are perfect for achieving peace of mind if you want a tranquil environment.
