How do noise-canceling headphones work? — Audiophile ON

Noise Cancelling Headphones or ANC Headphones (short for active noise canceling) are headphones that cancel out unwanted external environmental noise and leave you (in an ideal situation) with only the sound of your music being played through your headphones.

Before noise-canceling headphones went mainstream, if you wanted to improve your listening experience in noisy environments, you would be looking at getting a set of headphones with good isolation (Sound-isolating headphones).  Famous ones to give some examples would be the Etymotic ER4-SR or Sennheiser HD-25, which are both excellent sound isolators.

These are different from how active noise-canceling headphones work, as the reduction in external noise comes from insulating the listener’s ears from the external environment instead of removing it on ANC headphones.  

While there are many good isolating headphones, you will almost always find that some sounds can find their way inside these headphones.  These headphones rely on soundproofing to create an environment where users can focus on listening to their audio devices without interruption.

More recently, and mainly due to the popularity of one headphone company, Bose, there has been a dramatic increase in demand for active noise-canceling headphones.

Noise-canceling headphones are designed to reduce unwanted ambient sounds in the environment. They combine hardware and software to create an inverse sound wave that cancels the original sound wave. The result is a quieter and more immersive listening experience, especially in noisy environments such as airplanes, trains, or busy city streets.

Noise-canceling headphones are also useful for reducing the risk of hearing damage caused by listening to music at high volumes in noisy environments.