Active vs Passive Noise Cancellation

Of the five senses we are born with, we may not be able to control and protect each one although we can certainly have a direct impact on our hearing ability from a young age. Since younger students are not as conscientious about how loud noise levels affect their hearing, parents and teachers need to help make them aware of the importance of hearing protection. For teachers who provide headphones and headsets for their students on a regular basis, understanding the difference between ambient noise reduction and active noise cancellation can have a heavy impact on the future of their hearing ability so that their educational success does not also fade away.

Active noise control (like on the the Califone NC500TFC headphone), also known as sound field cancellation, reduces the sound of unwanted noises by electro-acoustical means. To accomplish this, internal circuitry (requiring power) within the headphone produces a mirror-image of the disrupting noise’s sound wave. When the two sounds collide they effectively cancel each other out, and the net result is no sound at all.

Active noise canceling headphoneIT director at the Blue-Ribbon Award winning “Sierra School” in Chatsworth, CA shares: “We could get by with the off-the-shelf brands for computer labs, but when kids really need to focus, we use the Califone headphones. We’ve noticed that they provide a higher sound quality and block out ambient noise better.

Passive noise reduction on the other hand doesn’t require power, costs far less than “active” noise canceling but offers slightly less cancellation. Passive ambient noise reduction means insulating the ear from the external noise. This tends to work best for middle and high frequencies – those which the human ear is most sensitive to. The best passive noise reduction is when an earcup completely and snugly covers the ears. There are a variety of different earcup sizes offering protection against ambient noise (there are three common sizes). Califone headphones and headsets with earcups covering the ears offer up to a 70%  noise reduction.   Over-ear styles of earcups offer significantly more protection against ambient noise than on-ear earcups, which in turn offer significantly more protection against the smaller ear buds, which fits in the ear canal.

Active and passive noise reducing headphones are not necessarily exclusive of each other. Headphones that provide active noise reduction can also passively reduce ambient noise levels when the cancellation feature is not enabled.

Read more about promoting safe listening practices with students.



Helping teachers and students with educationally appropriate classroom AV equipment since 1947.