The speaker driver is cone or diaphragm. There are mainly four types of drivers in the Speakers Tweeter, Midrange, Woofer and Sub-Woofer. Though these are the basic four drivers used in the speaker, there other speakers which have more drivers. There are drivers like “Balance Armature “which are smaller than other drivers. In small sized driver it possible to comprise more drivers. These design use cross over network. There are some full range speakers which simply need amplifier to power it. Midrange, Tweeter, Woofer and subwoofer can only capture portion of sound. These speakers need cross over. There are various combination available of it. Three way speakers consists a Tweeter, a midrange and a woofer. Finally four way speakers consists a tweeter, a midrange, a woofer and a sub woofer.
This driver reproduces high frequencies from 6000 Hz to 20000 Hz. High frequency sounds are quite directional.
Midrange is for middle tone like voice sound of Instrument. It reproduces the high frequencies from 500 Hz to 6000 Hz. Placement of it plays critical role as these sounds are directional.
Woofer is used for bass effect. It reproduces frequencies from 500 Hz down to 100 Hz. It does not require critical placement.
Reproduces the low frequencies 100 Hz down to 20 Hz. Subwoofer actually need when you are listening heavy beat. Sub woofer can be placed anywhere because it is Omni directional.
Cross over network
It divides the inbound speaker signal and distributes them to appropriate drivers.
This crossover can be placed either before the amplifier or after the amplifier. In low or medium range speakers it is placed after the amplifier. In high range speakers cross over placed before the amplifier.
Why drivers are critical
Combination of all these drivers is designed to smooth frequency response. As no single driver is capable to handle 20 Hz to 20000 Hz sound frequencies, combination of all these drivers is used to deliver full spectrum. It moves back and forth to create change in air pressure. It moves back and forth in corresponding fashion. The cone is actually moved by electromagnetic process. This process is caused by a coil of wire at the base of the cone. This coil is known as voice coil. The electrical current coming from amplifier drives the voice coil. The voice coil then interacts with permanent magnate attached to speakers coil and it activates the speaker the sound that we hear.