The benefits of this cannot be stressed enough, as it gives the user a great listening experience. The fact that no external noise can be heard is a big boost for users, and this also helps makers of these headphones, advertise and market these products better. After all, everyone wants a pair of headphones that drown out as much external sound as possible.
On the other hand, there are certain disadvantages of this technology as well. People who use these headphones while driving or riding put themselves and other people on the road at risk. Moreover, they can damage one's ear channels if the volume is constantly turned up beyond a certain limit.
The technology works on a pretty complex principle, and it would be extremely hard to understand for someone with no technical knowledge about sound waves and the way they travel. But at a simpler level, this technology simply obstructs the sounds, right at the source, rather than prevent it from entering the ear channels.
Sound travels through various mediums in the form of waves, and each of these waves has a certain shape. Now in noise cancellation headphones, there are certain microphones that determine the shape of these waves, the speed at which they are traveling, and the direction from which they are coming.
The microphones then connect with a digital signal processor that itself releases waves (known as antinoise signals), and these new waves counter the older ones, thus rendering them ineffective and useless. These two waves then cancel each other out, and the user is spared the sound that the original waves were bringing.
You must remember that active noise cancellation is still in its nascent stages, and this technology still has a long way to go. Even though one can buy pretty effective headphones in the market today, they do not prevent all noises from coming through completely. Fortunately, this technology will only get better over time.
As mentioned, this technology is still developing. As such, there are bound to be certain limitations and factors that one needs to keep in mind. These headphones require a separate source of power, and this is derived either from a USB cable and charging port, or from a set of batteries.
From time to time these batteries need to be replaced, or the charging port needs to be connected to a USB source. These headphones also produce their own noise sometimes, and this can annoy a user. These sounds come in the form of constant hissing. Moreover, the sounds that these headphones cancel are constant noises and hums, not sudden noises or speech.
Right now, such devices are made so that an individual can wear it around his ears and drown out outside noise. With further advancements, the concept of antinoise will be ready to be applied to sources that produce noise.
For now though, it is used by individuals to listen to music and to chat with people online. The scope of this technology is immense and there is a lot that can be achieved with it. It is only a matter of time before it starts surfacing in many others facets as well.