Headphones: What is "Passive Operation"? Does it have anything to do with noise cancellation? Or is it something completely different?

Question

In the specs for Sony WH-1000XM2 I see

Passive Operation: Yes

When I search the web for I find only "Passive Noise Cancellation" and "Active Noise Cancellation". What is "Passive Operation"?

Answer 1

In passive operation mode, no amplifier is involved so just the signal coming from the input lines is reproduced and provides the power to the speaker membranes. This is impossible with bluetooth, where the signal received must be amplified, since the radio waves do not convey sufficient energy to move the membranes.

You may compare that to a water pipe: You have the level, where you just know, that it is connected and able to provide some trickling water and the level where it is sufficiently powerful to get decent rays out of a shower or sufficient energy to turn a sprinkler. With radio transmission (as bluetooth) you always have the low level (amplifier needed, therefore active), while with a sufficently short wire the high level may be achieved.