How does the diaphragm move?
 

The diaphragm does not move piston-like, as in cone loudspeakers, the flat diaphragm vibrates on its own axis. The bending waves move from the middle outwards, comparable to the wave movement on a water surface after throwing in a stone.

Using Mother Nature as as example, the Basilar diaphragm of the human inner ear functions along the same wave principle as the Manger sound transducer.