What is Passive Noise Cancellation or Noise Isolation? How is it Different from Active Noise Cancellation (ANC)?


In the list of gadgets to carry while you are traveling, headphones definitely are in contention for one of the top spots. It does not matter if you are flying across the world or just walking a couple blocks, earphones are often just as attached to our ears as they are to our phones. 

Not too long ago, we tried to explain the concept of active noise cancellation and what difference it makes in a pair of headphones. Although definitely useful, the feature can add a lot to the price of earphones.

Fortunately, there is an alternative — a close cousin of active noise cancellation which comes in all earphones or headphones (we are going to be using the terms interchangeably), and is not as expensive as ANC.

We are talking about passive noise cancellation, or, noise isolation.

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As discussed in the previous article, earphones with active noise cancellation have microphones that measure ambient noise. They then produce sound waves equal to those ambient noise sound waves, cancelling them out and giving you a disturbance free audio experience. But these microphones on earphones can burn a deep hole in your pocket. And if budget is a constraint (as it so often is), you can just look out for a pair of earphones that isolates noise the best.

As the term suggests, noise isolation or passive noise control is basically, isolating ambient sound. It is as simple as covering your ears with your hands to reduce the level of sound entering your ear. Unlike active noise cancellation which is a part of the mechanics of a headphone and involves an actual mechanical process (microphones gauging sound and emitting sounds to cancel them out), passive noise cancellation is more about the design.

The degree of noise that will be blocked by passive noise cancellation depends on the type of headphones or earphones, the design of the ear cups, how well they fit into and cover the ears of the user. So, headphones with thicker padding and more insulation, and earphones that fit most snugly into your ears, cancel out the most noise, passively. 

Because passive noise cancellation is not about what is inside the earphones, but all about the outside of it, this feature does not require any power. It is also more cost efficient as compared to its more geeky brother, active noise cancellation, which depends on power and costs much more. And unlike active noise cancellation which is an added feature, all earphones or headphones come with some sort of passive noise cancellation as they cover our ears – hey, they all try to keep out ambient sound, don’t they? Else we would not bother wearing them.

So, does all this make passive noise cancellation better than active noise cancellation? Well, we are not too sure about that. Yes, passive noise cancellation is more affordable and simple but it will not give you the same result and as good an audio experience as a pair of headphones equipped with active noise cancellation would. For, no matter how well you design a pair of headphones or earbuds, a little bit of ambient sound does tend to leak in (it all depends on where you are).

Passive noise cancellation or noise isolation is great if you are on a tight budget. Depending on the conditions, it can definitely make a difference. But if you want external sounds almost totally jammed out while you listen to your audio, then you might want to consider earphones that offer active noise cancellation.

Traveller’s Tip: We generally recommend passive noise cancellation or noise isolation headphones for travellers who walk a lot. Quite simply because they need to hear a bit of what’s around them, be it people, traffic, birds or animals. Silence might be golden but not hearing a vehicle close to you because of your headphones can be VERY injurious to health. 



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