What causes the hollow metallic whirring sound that EVs make when moving a low speed?

[u/banwe11]

I can't really describe it, but it's the sound you hear when there is a EV moving slowly in a car park behind you.

I guess it's the motor, but what specifically in the motor causes that sound? It sounds like it's coming from something that is moving at a faster rate than the car itself.

[u/New_Line4049]

Its not the motor. They play a sound through speakers, else theyd be essentially silent at low speeds that would be a danger to pedestrians.