How Noise Cancelation Headphones Work

How Noise Cancelation Headphones Work

There is a lot of confusion about how noise cancelation headphones work so we thought we should take a moment and answer a few questions about how they work and provide a little advice to anyone shopping for a good set of noise reduction headphones.

Active or Passive Noise Cancelation

There are two main types of headphones that block sound. Some headphones block sound by sampling the ambient noise with tiny microphones built into the headphones. Then an “equal but opposite” cancelation sound wave is generated inside of the ear cups to “cancel” the sound you hear. This technology is call active noise cancelation and is very effective at blocking consistent, rumbling or humming noises like the airplane engine noise you hear when flying or the sound of an air conditioner or fan. It is “active” because there are microphones and electronics actively trying to sample the ambient noise and then figure out how to cancel it before it reaches your ears. Active noise cancelation headphones tend to be fairly compact in size and some models sit on your ear rather than having the ear cups enclose or surround your ear. Active noise cancelation headphones always require batteries to run the electronics that cancel the sound. When the batteries die, so does the noise cancelation – and sometimes, depending on the set of headphones, you can’t hear any music at all if your headphone batteries die. Also, active noise cancelation headphones produce a hissy swoosh noise inside of the ear cups. This is the “canceling” sound wave. It makes your music sound like there is a hissing staic in the background which I hate. I like clear audio and active noise cancelation headphones do not really produce very clear sound.

The other type of noise blocking headphones are passive noise reduction or passive noise cancelation headphones. Passive noise cancelation headphones work by physically blocking the sound from reaching your ears. The ear cups have closed backs and totally enclose your ear. This style of headphones tend to be a bit bulkier than active noise cancelation headphones because the ear cups are packed with noise isolation foam and the ear cups need to be large enough to totally enclose your ears and protect them from sound. Passive noise reduction headphones like the Direct Sound Extreme Isolation Headphones are generally much better at blocking sound and also significantly less expensive. There has been a great deal of marketing hype around fancy headphones like the Bose Quiet Comfort headphones, but the truth is that the headphones at actually block more noise. For example, the EX-29 Extreme Isolation headphones will reduce noise by 29dB across the entire audio spectrum – low noises and high pitched noises alike. Active noise reduction heapdhones only block 12dB to 17dB of sound. Also, since passive noise reduction headphones do not produce that canceling sound wave, the audio is crystal clear. With the studio quality speakers in the EX-29 headphones you will hear the fine details of your music that you have may have never heard before.

Blocking Noisy Voices

If you need to block out office chatter, TVs, phones ringing and other spiky sounds like that, your only option is a good set of passive noise reduction headphones and a white noise audio track. Active noise cancelation headphones can’t calculate a canceling sound wave fast enough to block out these types of sounds. Passive noise reduction headphones, however, block out all types of sounds. No matter what type of headphones you choose you will still be able to hear background noise. It would take over 60dB of sound reduction to provide complete silence and that is only achieved in expensive recording studios. Headphones simply can’t block that much noise so there is going to be some background noise that you hear. But if you listen to a white noise audio track (comes free with your purchase at you can mask out virtually all background noise. This is a GREAT solution if you need to concentrate or study.

Do I Need Batteries?

Another really important thing to consider is the ongoing cost of having to replace batteries every month in active noise cancelation headphones. With the Extreme Isolation headphones there are no ongoing costs because they do not use batteries. So be sure to figure the cost of 2 AAA batteries per month into your budget if you are considering the purchase of active noise cancelation headphones. Let me also reissue the warning that if your batteries die on you, your headphones may stop working altogether and you will certainly lose your noise cancelation feature.

Leaking Noise

One last point before I summarize why I recommend the the Extreme Isolation headphones, and passive noise reduction headphones in general, is not only do they block outside sound from coming in, they keep your music from leaking out and disturbing other people. Some people even use the EX-29 Extreme Isolation headphones in studios where sound leaking out of the headphones and into microphones can be a real problem. With the EX-29 Extreme isolation headphones you can start listening to some music then take the headphones off and press the ear cups together. You will be amazed when you realize that virtually ALL of the sound is kept within the headphones. At normal listening levels, if you take the headphones off your head and press the ear cups together you can’t hear any sound leaking out.


So, in summary, we recommend passive noise reduction headphones and, in particular, the EX-29 Extreme Isolation Headphones from

  • Excellent value for the money
  • 6 month, 110% money back guarantee (you don’t see that on products that don’t work)
  • No batteries
  • Blocks more sound than active noise reduction headphones
  • No sound leaking out
  • Best sound and no swooshy hiss
  • Free white noise MP3 comes with your purchase!