Inside a speaker you will find a cone, an electromagnet and a permanent magnet. For a speaker to change an electrical signal into a sound that can be heard, speakers have an electromagnet, which is a metal coil that creates a magnetic field when electric current flows through it. This coil operates much like a normal magnet, with one particular quality; turning backwards the direction of the current in the coil flips the poles of the magnet. In the interior of a speaker, an electromagnet is positioned in front of a permanent magnet. The permanent magnet is put firmly in place whereas the electromagnet is mobile. As pulses of electricity go through the coil of the electromagnet, the direction of its magnetic field is quickly transformed. This means that it is in turn attracted to and turned away from the permanent magnet, vibrating back and forth. The electromagnet is joined to a cone created of flexible material such as paper or plastic which increases these vibrations, producing sound waves into the surrounding atmosphere and towards your ears.