Noise Canceling
Headphones: How They Work
Chances are you have heard of noise canceling headphones. These devices use various methods to drown out the ambient sounds around you. The result: a more enjoyable listening experience that is no longer plagued by the distracting noise of your surroundings.
Noise Canceling Headphones: Two Methods
The idea behind noise canceling headphones is in the name; they are designed to "cancel" the noise
before it has an opportunity to assault your eardrums. One
thing to keep in mind, the term noise canceling is a bit
optimistic. While a quality pair will greatly reduce the
noise you
hear, they will not be able to eliminate all of it. With that
said, there are two types of cancellation methods for headphones;
passive and active.Passive Noise Canceling Headphones
Passive cancellation employs the concept of blocking sound waves. With passive cancellation, insulation is used to create a barrier between your ears and the incoming waves of noise. Sealed or closed headphones are an example of those that incorporate passive cancellation to isolate listeners from their environment.Active Cancellation and Destructive Interference
Active cancellation is the type most people think of when it comes to noise canceling headphones. The principle behind this type of cancellation is destructive interference. Destructive interference takes place when a wave collides with another wave with opposite crest and trough positioning. The crest is the top of the wave while the trough is the bottom. When the two collide, the amplitudes, or heights, of the waves are decreased. In the case of sound waves, the amplitude is the sound's volume.