Individual moving element of a complete speaker system which is attached to the speaker enclosure and which vibrates, generally in a back and forth piston like motion, to produce sound waves when power is applied from an amplifier. A speaker driver is technically a speaker itself though a speaker is generally referred to as the combination of drivers, enclosure, crossover and other components which make up an entire speaker as we normally experience it. he driver is composed of a basket, a magnet, a voice coil, a spider, a surround (also called suspension) and the actual moving drive unit or diaphragm (usually a cone or dome). The basket essentially holds all the pieces together so that the unit can operate and move. The speaker drive element (diaphragm) is attached to the basket at the front (the wide round portion of the drive unit) by the surround or suspension. The surround is a flexible material that holds the drive unit (diaphragm) in place and seals the drive unit to the basket. At the rear of the diaphragm are the spider and voice coil with the voice coil attached to the diaphragm. he voice coil is essentially an electromagnet made up of a long, fine wire wrapped around a cylindrical structure. Speaker wire coming from the amplifier actually attaches to the voice coil to cause motion and thus sound waves (although speaker wire is normally attached outside the speaker enclosure to binding posts of some sort, there is an internal wiring connection from the binding posts to the voice coil usually going through a crossover first). The voice coil is held in close proximity to the magnet by the spider. The spider is a semi-rigid material that holds the back of the speaker driver and voice coil in the proper relation to the magnet while also working to bring the speaker drive unit back to its resting position after it has moved forward or backward (somewhat like a spring or bungee). The magnet is attached the basket and held close to but not touching the voice coil. s electric current is applied to the voice coil, it creates an electromagnet. The electromagnetic force varies in intensity and polarity (positive or negative) allowing it to move in varying degrees forward or backward relative to the magnet. As the voice coil is energized and it creates an electromagnetic field, that field either attracts or repels the voice coil from the magnet. Since the magnet is stationary in relation to the voice coil, the voice coil itself moves. Being attached to the speaker diaphragm, the voice coil’s movement translates into movement of the speaker driver itself. ll of these components working together make the driver move (the movement is extremely rapid – a 20 kHz frequency commonly produced by a tweeter or high frequency driver moves 20,000 times per second or 20,000 cycles). This driver movement moves the air surrounding the driver to create sound waves that we can hear.