Noise Cancelling Is Best at Hum, Worse at Voices

Noise cancelling is very good at steady, low-pitched noise — engines, road roar, air conditioning — and noticeably worse at voices and sudden sounds. Sony’s own help guide says its noise cancelling “works primarily on noise in the low frequency band such as vehicles and air conditioning”, and that the noise “is not completely canceled”.

Bose says the same in plainer words: steady background sounds are “usually easier to reduce than sudden or unpredictable ones”, and voices are harder still “because they change quickly and cover a wider range of sound”.

How it works

Noise-cancelling headphones block sound two ways. The first is physical: ear cups, cushions or silicone tips that stop sound before it reaches you. Bose calls this passive isolation. The second is electronic, and it is the part the word “active” refers to.

Apple’s support page describes that part step by step. An outward-facing microphone picks up the sound around you, and the AirPods “counter with anti-noise, canceling the external sounds before you hear them”. A second, inward-facing microphone “listens inside your ear for unwanted internal sounds”, and the AirPods cancel those too. Sony calls its version “antiphase sound” generated against the noise around you. The microphones and the anti-noise are the active part; the seal is the passive part, and Bose says the two “work best together”.

Only two of the four makers say which noise the electronics handle best:

	Reduced well	Reduced less	Source
Sony	Low-frequency noise: vehicles, air conditioning	Not stated by type; “not completely canceled”	WH-1000XM6 Help Guide
Bose	Steady noise: cabin, road, air-conditioning hum	Voices; sudden or unpredictable sounds	Bose Stories
Apple	Not stated by type	Not stated by type	Support 108918
Samsung	Not stated by type	Not stated by type	Support ANS10001322

None of the support pages we read puts a decibel figure on how much noise any pair removes. Where Apple publishes a number at all, it is relative: its release says AirPods 5 (affiliate link to Amazon, opens in a new tab) remove “up to 50 percent more noise compared to AirPods 4 with ANC”, with no test conditions, as our AirPods 5 launch piece pointed out. AirPods 5 are also an open-ear design, with no silicone tip sealing the ear.

Fit is half of it

All four makers we read point to fit before the electronics. Bose says “a better seal helps block more outside sound”. Sony’s first fix for weak cancelling is to put the headset back on. Apple’s fit guide says properly fitted AirPods Pro should “create a good acoustic seal for optimal sound quality and noise cancellation”, and the iPhone can run a test that measures that seal. Samsung’s page on weak noise cancelling suggests a different ear tip size first.

The makers also list the ways the electronics go wrong, and they are useful to know before deciding a pair is faulty:

• Covered microphones. Sony says a hand over the microphones can stop noise cancelling working or cause a beeping feedback sound.
• Too quiet a room. Sony says that in a very quiet place “you may not feel the noise canceling effects, or you may feel that some noise is increased”.
• Earbuds too deep. Samsung says some Galaxy Buds can whistle if worn too far into the ear.
• A false trigger. Samsung says humming such as an electric toothbrush can switch on its conversation-detection feature, which temporarily turns noise cancelling off.

The other modes, by name

The opposite of cancelling is letting sound in on purpose. Each maker uses the outside microphones to pipe surrounding sound through, so you can hear a train announcement without taking the headphones off. Apple’s page says simply that Transparency “lets outside sound in”. The names differ more than the idea:

Maker (model read)	Cancel noise	Let sound in	Automatic
Apple (AirPods with ANC)	Active Noise Cancellation	Transparency	Adaptive, a separate mode
Sony (WH-1000XM6)	Noise canceling	Ambient Sound Mode	Auto Ambient Sound, inside Ambient Sound Mode
Bose (QC Ultra Headphones 2nd Gen)	Quiet	Aware	ActiveSense, inside Aware only
Samsung (Galaxy Buds3 Pro (affiliate link to Amazon, opens in a new tab))	Active noise canceling	Ambient sound	Adaptive sound, plus automatic switching

Bose adds Immersion and Cinema, which are full noise cancellation with its spatial audio switched on, not a different level of cancelling.

“Adaptive” is the word to read carefully, because the four makers mean four different things by it. Apple’s Adaptive “blends Active Noise Cancellation and Transparency mode together” as conditions change, and on iOS 27 a slider sets how much outside noise it allows. Bose’s ActiveSense adjusts cancelling to the volume around you, but Bose says it is “only available in Aware mode”. Sony’s Auto Ambient Sound adjusts how much outside sound it lets in when things get noisy. Samsung’s Buds3 Pro can switch modes for you: Ambient sound when it detects a siren, noise cancelling when it detects loud noise such as construction.

Two makers also say their ordinary noise cancelling adjusts itself. Sony’s help guide says performance is “automatically optimized” to how you wear the headset, so “you may notice fluctuations”. Samsung’s says its Adaptive Active noise canceling responds to fit and surroundings, and that “changes in Active noise canceling performance are normal”. On their pairs, cancelling that seems to rise and fall by itself is what the makers describe, not a fault.

Transparency has limits of its own. Sony warns that wind noise can rise in Ambient Sound Mode, and that depending on your surroundings and playback volume, you may not hear outside sound even with it on.

Samsung disagrees with itself

Samsung’s US article on using noise cancelling says the feature is missing only from the original Galaxy Buds and the Buds+, and gives fixes for the Buds Live, Buds Pro, Buds2 and Buds2 Pro. Its troubleshooting article on changing noise-cancelling levels says noise cancelling “is supported only on the Galaxy Buds4 and Buds3 series”. The second may mean the adaptive version only, which the page is about, but it does not say so. Check your own model’s page.

What this means for buying

If what you want to block is a plane cabin, a train or an office air conditioner, that is the noise Sony and Bose describe cancelling best. (On a plane, check which airlines’ seatback screens take Bluetooth.) If it is a colleague talking, expect it quieter but still there. On our earbud shortlist, the Bose QuietComfort Ultra Earbuds (2nd Gen) are the pair reviewers single out for noise cancelling, and our over-ear headphone shortlist covers only noise-cancelling pairs. Whichever you choose, the fit test is the cheapest improvement available.

Mode names on the box tell you less than the manual does: the same gap between marketing and documentation we found when two-device Bluetooth turned out to switch LDAC off.

Questions people ask

How does noise cancelling work?

Microphones on the outside of the headphones pick up surrounding sound, and the headphones play an opposing signal, which Apple calls anti-noise and Sony calls antiphase sound, so the two largely cancel. Apple’s AirPods also use a microphone inside the ear to catch what is left.

What noise does noise cancelling block best?

Steady, low-pitched noise. Sony says its noise cancelling works primarily on low-frequency noise such as vehicles and air conditioning, and Bose names airplane cabin noise, road noise and air-conditioning hum as where the effect is most noticeable.

Do noise cancelling headphones block voices?

Not completely. Bose says voices are harder to cancel than steady background noise because they change quickly and cover a wider range of sound, so nearby conversation may still come through.

What is transparency mode on headphones?

It uses the outside microphones to pass surrounding sound through to you, so you can hear announcements or traffic with the headphones on. Apple calls it Transparency, Sony Ambient Sound Mode, Bose Aware and Samsung Ambient sound.

What does adaptive noise cancelling do?

It changes the balance between cancelling and letting sound in, automatically, as your surroundings change. Apple’s Adaptive is a mode of its own; Bose’s ActiveSense works only inside Aware mode; Samsung and Sony also adjust noise cancelling to fit and surroundings.

Why does my noise cancelling feel weak?

Fit is the first thing every maker points to. Apple says a good acoustic seal is needed for the best noise cancellation, Samsung suggests a different ear tip size, and Sony says to put the headset back on. Covering the microphones can also cause feedback.

Does noise cancelling work without music playing?

Yes. Bose says active noise cancellation works independently of your audio, so it reduces surrounding noise even in silence, and is most noticeable with steady sounds such as cabin noise or air conditioning.