By constantly receiving input on how to move, and being able to respond immediately and accurately to any such signal.
Microphones and speakers are similar. Just as a microphone responds to any kind of sound that it can, and a recording device records all the sound that comes in, no matter what it is (to the best of its ability), a playing device plays that same information, and a speaker attempts to reproduce it by vibrating just like the recording device did when it recorded the sound.
Nothing about that is limited to playing one note at a time. In fact, it isn’t even about notes at all. It’s reproducing the sounds that were recorded, whatever they were at the location of the microphone(s).