I pressed again, and the voice said “Off”. The outside noise went back to what it had seemed before “Ambient sound”. I pressed a third time. “Noise cancelling,” said the voice. The noise? Identical, it seemed to me.
I went to a quiet place and cycled through again. Whenever I got to “Noise cancelling”, a fraction of a second after the announcement I could sense the distinctive application of noise cancelling. It’s common to all active noise cancelling headphones. It feels as though there is sudden, slight variation in room pressure, accompanied by just barely perceptible white noise. Modern noise-reducing headphones keep this effect down to something you really have to listen for, so there’s no discomfort involved.
So, it seemed, something was happening. But nothing that reduced the noise.
Standard noise reduction test time! I played a video clip I took on a turbo-prop airplane a couple of years ago at an average of 100dB (C-weighted). I switched the noise cancellation on and off. No perceptible difference. I played a crowd noise I recorded last year at 90dB (C-weighted). No effect. I turned that down to 80dB. No effect.
For all practical purposes, the noise cancellation in these earbuds does nothing.
The Sony Sport WF-SP700N earphones are actually very good earbuds, well designed, comfortable and with respectable sound. Just don’t expect to get anything much out of the active noise cancellation.