Active noise cancelling (ANC) and call noise reduction (often labelled ENC) solve two different problems. ANC reduces the noise you hear while you listen. Call noise reduction reduces the noise the other person hears when you talk. Both use microphones, which is why spec sheets mix them up, but one does not imply the other: a pair of earbuds can have excellent ANC and average calls, or clean calls and no ANC at all.
Two features, two directions
| Feature | Who it helps | What it does | Names you will see |
|---|---|---|---|
| Active noise cancelling | You, the listener | Microphones sample outside noise and the earbuds play an opposite anti-noise signal | ANC, hybrid ANC, adaptive ANC |
| Call noise reduction | The person on the other end | Microphones and processing try to keep your voice and suppress background sound before it is sent | ENC, cVc, AI call noise reduction, Voice Isolation |
| Transparency or ambient mode | You | Lets outside sound in on purpose | Transparency, Ambient, Aware |
How ANC works
Apple describes the process for AirPods clearly: outward-facing microphones detect external sounds and the earbuds counter them with anti-noise, while an inward-facing microphone listens inside your ear for unwanted sound that got through and cancels that too. Sony's help guides describe the same principle as generating antiphase sound against the noise around you.