When evaluating noise cancelling headphones, the two varieties that you will see are active and passive. The passive models offer noise reduction as opposed to noise cancellation. With them, users have outside noises effectively blocked as a result of the acoustic seal the headphones achieve around the ear. This isn’t actually a type of technology since it is basically just a more advanced version of covering your ears with your hands.
That’s where active noise cancellation technology comes into play. With this type of technology (yes, it’s actual technology unlike it’s passive sibling), the headphones create frequencies that in essence match or cancel out the outside noises. The end result is that annoying background noises are made less noticeable, or sometimes not even noticeable at all.
To achieve this sort of technology, you have features in a pair of active noise cancelling headphones that are absent in more traditional passive models. Typically, an active design is powered by a battery – either AA or AAA – to create the actual noise cancellation. This means that once the battery dies, so does the noise cancellation ability until you replace it with a fresh battery.
In order to know what kind of noises you are dealing with, a microphone is also present in the device. It’s purpose is to pick up the ambient noise in your environment, such as the whirring of a plane engine. It works with some special noise cancelling circuitry in the hardware to effectively erase that ambient noise. By evaluating your environment’s noise, the headphones know just what frequencies it takes to counteract what you’re hearing. The end result is that nice peaceful oasis that you crave.
Granted, some devices are more effective than others when it comes to blocking out the unwanted noises. But even the cheaper models do a pretty good job of at least reducing the sounds that you do not want to hear.
If you are in the market for a good pair of active noise cancelling headphones, then I urge you to check out my reviews of the top models for 2014. There I give you my top picks, with something to meet any budget.