Ambient, background noise cancellation with headphones plugged in; does it still cut out the background noise?

That’s what the iPhone does when you’re using it held to your ear. The ambient noise microphone on the iPhone samples the background noise to both clean up what you hear in your ear, as well as to focus the microphone on your voice. The earbuds don’t do that, and the iPhone’s system is not active when using the earbuds.

Airbuds do both as well - they focus the microphone on your voice and clean up what you hear. And the Pioneer Rayz lightening earbuds that Apple sells also do that - they filter out background noise to both the earbuds and the microphone. But in both those cases, it is the headphones themselves providing that active noise cancellation, not the iPhone (part of the reason why both airbuds and Pioneer Rayz are so expensive).

You need to think about the acoustics that are involved in noise cancellation. The way it works is it samples the sound going into the microphone on the bottom of the phone and the sound going into the noise suppression mic on the back of the phone. Your voice is in sync on both because they are close together, so it knows that your voice is not noise. Sound that goes into them and that is out of sync is noise. But when you are using a headset it can be far away from the noise suppression mic so you voice will be out of sync between the headset and the noise suppression mic, so if noise cancellation was enabled it would block your voice. As usual, physics rules.

The solution is to use a headset that has built in noise suppression.

Only if you are using headphones with their own built in noise cancellation, which the included earbuds do not have. AirPods do have a method of noise cancellation built in.

Hello,

Noise-cancellation does not work when using headphones.

Good luck.