Noise Cancelling Headphones: How Do They Work?

Regrettably for music fans, many types of ambient noises can interfere with or even block the sounds coming through their headsets. If you have ever strained to listen to a CD or MP3 player on a plane, then you know the problem well: The roar of the engines makes it hard to hear what is being piped through the speakers, even when those speakers are located in or on your ear. Luckily, noise-canceling headphones can offer a more enjoyable listening experience.

Noise-canceling headphones come in both active and passive types. Technically speaking, any type of headphone can provide some passive noise reduction. That is because the materials of the headphones themselves block out some of sound waves, particularly those at higher frequencies. The best passive noise-canceling headphones, though, are circum-aural types that are especially constructed to maximize noise-filtering properties. That means they are packed with coatings of high-density foam or other sound-absorbing material, which makes them heavier than normal headphones. The compromise of all that extra weight is a reduction in noise of about roughly 15 to 25 decibels. Nonetheless, considering jet engines generate 75 to 85 dB of noise inside the aircraft cabin, passive models have some serious margins. That is where active noise-canceling headphones come in.

Noise-canceling headphones can do the whole lot that passive ones can do - their very arrangement produces a barrier that blocks high-frequency sound waves. They also add an additional level of noise reduction by actively removing lower-frequency sound waves. How do noise-canceling headphones achieve this? They essentially generate their own sound waves that mimic the inbound noise in every respect except one: the headphone's sound waves are 180 degrees out of point with the intruding waves.

You should notice that the two waves, the one approaching from the noise-canceling headphone and the one related with the ambient noise, have the same fullness and frequency, but their compressions and rarefactions are set so that the compressions of one wave line up with the rarefactions of the other wave and vice versa.

These headphones have taken 10 years to develop and are now cancelling 90 percent of incoming noise and are able to bring in maximum sound for your entertainment. But, as mentioned above when inside an aircraft the sound of the engine is at a point of actually hurting your ears and so when avionic equipment is required this includes headsets. Century Avionics has top of the line headsets for all your avionic requirements that also block out the roar of an engine. So please do go visit them and see for yourself.

Source : articlesbase.com