The moving element of a loudspeaker that vibrates, normally in a back-and-forth piston motion, to produce sound waves. A driver is technically a speaker itself, although the term “loudspeaker” usually refers to the combination of drivers, enclosure, crossover, and other components, which make up an entire speaker system.
The components of a typical driver are the basket, an electromagnet, a voice coil, a spider, a surround (also called a suspension) and the actual moving drive unit or diaphragm (usually a cone or dome). The basket is the frame that holds all the pieces together. The drive element (diaphragm) is attached to the basket at the front (the wide round portion of the drive unit) by a flexible surround to allow controlled back-and-forth motion. Attached to the rear of the diaphragm is the voice coil, which is kept centered by a device called a spider.