Noise blocking vs. noise cancelling

Explore the key differences between the types of noise-reduction technology.

Woman sitting in a chair wearing Bose QuietComfort Ultra Earbuds

As you venture into the world of headphones, you’ll encounter technical terms that may initially seem interchangeable. Is it noise cancellation or noise blocking that you’re after? There’s a meaningful difference, and understanding these terms is crucial in finding the right technology for your needs. Whether you’re aiming for deep focus or a quiet escape from the world, we’re here to help.

Noise blocking

Also known as passive noise reduction or noise isolation

A term like noise blocking sounds like a high-tech solution, but it’s actually very low tech. It can be as simple as plugging your ears with your fingers, creating a physical barrier against the noise.


This technique, called passive noise reduction, relies on physical obstruction rather than electronic components. Essentially, anything that covers your ears can act as a passive noise blocker, requiring no built-in technology, microphone, or power source.


While it may be low-tech, noise blocking plays a crucial role in headphone design. When executed effectively, it serves as the first line of defense against unwanted sounds. Achieving a tight seal on an earcup or a snug fit with an earbud can significantly enhance performance.


Given the diverse shapes and sizes of human ears, there’s been extensive research and testing to ensure optimal noise blocking. We’ve scanned hundreds in the pursuit of better fit and comfort to ensure optimal noise blocking. The latest Bose QuietComfort Ultra Earbuds eartips used with our true wireless earbuds are a testament to the importance of human form factors in our innovations.

The bottom line: While noise blocking is effective, it needs to work in tandem with a technology, like active noise cancellation, in order to lead you to a more sophisticated solution.

Works best for casual listening, taking a stroll, or making conversation.

Woman wearing Bose QuietComfort Ultra earbuds while dancing

Noise cancelling

Also known as active noise cancelling or active noise reduction

Noise cancelling, a term you’ve likely come across, is a technology that might be exactly what you’re after. It’s different from noise blocking and passive reduction because it involves active technology.


Bose was the first to use Acoustic Noise Cancelling or ANC in headphones when we invented the category over 20 years ago — a legacy that will always be tied to our brand. We could talk ANC all day long, but let’s cover the basics.


Noise cancelling headphones operate with powered technology, meaning they require energy, typically from a rechargeable battery, to function. But even without power, you still benefit from the physical noise blocking simply by wearing the headphones. Once you power them on, that’s when the active technology comes into play.

How does noise cancelling work?

Noise cancelling headphones monitor the sound around you, preventing the unwanted noise from ever reaching your ears based on battery power, signal processing, and various noise-blocking techniques. But ultimately, miniature microphones in the earcups or earbuds listen to the outside noise frequencies and emit the exact opposite signal to effectively “cancel out” both sets of sounds when the soundwaves collide.

Where noise blocking is a physical barrier to keep out sound, noise cancelling happens silently in the background, creating an audio “barrier.”

When are the best times to wear noise cancelling headphones or earbuds? Devices like the Bose QuietComfort Headphones, QuietComfort Ultra Headphones, or QuietComfort Ultra Earbuds are perfect for situations when you’re serious about enjoying your music, audiobooks, podcasts, shows, or movies without external noise getting in the way. Noise cancelling headphones are becoming a part of everyday life, with more and more people using them for work, calls, travel, and focused time at home.

Hopefully, we’ve untangled the differences between noise blocking and noise cancelling. Now that you have the right terms, finding the right tech all depends on how and where you want to manage the sounds around you.


Product availability may vary by country.


Works best for travel, focus, and commuting.

 Man with Bose QuietComfort Headphones hanging around his neck while outside

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