A loudspeaker is a system that transforms an electric signal into a mechanical signal. At the heart of this system we find a coil made of conducting wire, carrying an electrical current, which moves under the effects of magnetic forces. A flexible membrane (or diaphragm), attached to the coil, acts like a piston that pushes the surrounding air. This animation has been slowed down many thousands of times -- audible signals lie between 20 and 20,000 Hz.

Rollover the speaker to display the parts.