Audio speaker coils, also known as voice coils, are an integral part of a loudspeaker that converts electrical signals into mechanical vibrations that produce sound. They play a vital role in generating sound waves by interacting with the speaker's magnet and diaphragm. 

CONSTRUCTION: Loudspeaker coils are usually made of insulated copper wire, tightly wound on a bobbin in the shape of a cylinder or molding machine. The wire used is specially selected for its conductivity and heat resistance.

Design: The design of a speaker coil depends on factors such as speaker size, power handling capability and desired frequency response. The number of windings, wire gauge and coil diameter will affect the impedance and overall performance of the coil.

Function: When an audio signal is sent through a speaker's voice coil, it creates a changing magnetic field around the coil. This magnetic field interacts with the permanent magnets of the speaker assembly, causing the coil to move back and forth in response to the electrical signal. This movement drives the diaphragm and produces sound waves.



Impedance: The impedance of the coil (measured in ohms) affects the overall electrical characteristics of the speaker and its compatibility with audio amplifiers. The nominal impedance of a speaker is usually specified to ensure proper matching with the amplifier.

Heat Dissipation: Speaker coils generate heat during operation due to the passage of current. Adequate heat dissipation is essential to prevent overheating and potential damage. Some speaker designs employ cooling mechanisms such as vented voice coils or heat sinks to enhance heat dissipation.

Dual Voice Coil (DVC): In some loudspeaker designs, particularly subwoofers, a dual voice coil configuration is used. These speakers have two separate voice coils wound on the same coil frame, allowing for more flexible wiring options and impedance configurations.

The performance and quality of a speaker's coils can significantly affect a speaker's overall sound reproduction. Factors such as coil material, winding technique and coil design all affect a speaker's efficiency, power handling and frequency response.