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 headphones 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.

Wireless Headphones

Active Noise Canceling Headphones

    Active noise canceling headphones use a small microphone and electronics for their task.  When a sound reaches the microphone, the signal is passed along to the electronics which recreates an inverted version of the sound wave.  The incoming wave and the electronically created one interact, thereby reducing the volume of the ambient sound.

Noise Canceling Headphones: Final Thoughts

    Active noise canceling headphones are not only great for listening to music or watching movies in a noisy home, they also work well for traveling.  It is believed that all of the noise associated with flying, the other passengers and the plane itself, contributes to the fatigue you feel afterward.  By using noise canceling headphones, you can reduce the effects of this noise pollution.  If you live in a noisy home or travel often, you will definitely be glad you picked up a pair.