Tightly wrapped coil of wire attached to a speaker driver’s diaphragm and situated in close proximity to a stationary magnet; electromagnet that generates a magnetic field when current passes through it thus being repelled or attracted by a speaker driver’s magnet and creating motion. hen two magnetic forces are both positive or negative (the same polarity), they repel one another. When they are of opposing polarities (one positive and one negative) they are attracted to one another. As power passes through the voice coil, it creates varying magnetic fields of more or less power. This creates an attraction to or repulsion from the stationary magnet in varying degrees. Thus the voice coil moves closer to and farther from the magnet in correspondence with the audio signal being fed into it. Since the voice coil is attached to the diaphragm (the actual moving drive unit; primarily a cone or dome), it moves the diaphragm as it moves. The rapid fluctuations in the input signal create rapid movements in the voice coil and consequently the diaphragm, which excites the air around the speaker and generates sound waves. oice coils are primarily formed of very long lengths of copper wire wrapped around some form of cylindrical structure. The magnet may then be placed inside the cylinder or may surround the cylinder (the magnet surrounds the voice coil in most cases). Large, powerful magnets are used to generate a strong magnetic field in which the voice coil moves. The interaction between the voice coil and magnet allows dynamic speakers to generate sound.