Loud-speaker

Loudspeaker

A loudspeaker (or speaker) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. The most widely used type of speaker in the 2020s is the dynamic speaker, invented in 1925 by Edward W. Kellogg and Chester W. Rice. The dynamic speaker operates on the same basic principle as a dynamic microphone, but in reverse, to produce sound from an electrical signal.

History

The development of the loudspeaker began in the late 19th century and was primarily driven by the desire to increase the volume of telephone and phonograph systems. Early experiments with electromagnetic devices for sound reproduction were conducted by Alexander Graham Bell, Ernst Siemens, and Thomas Edison, among others. The first practical moving-coil loudspeakers were developed independently by Kellogg and Rice in the early 1920s.

Design and Function

The primary components of a loudspeaker are the diaphragm (often referred to as the speaker cone), voice coil, magnet, and suspension system. The voice coil is attached to the apex of the diaphragm and is positioned in the magnetic field of the magnet. When an audio signal is passed through the coil, it induces a magnetic field that interacts with the field of the permanent magnet, causing the coil and the attached diaphragm to move back and forth. This motion pushes on the air to create sound waves.

Types of Loudspeakers

There are several types of loudspeakers, each designed for specific applications and performance criteria:

• Dynamic loudspeakers: The most common type, using a lightweight diaphragm and a magnetic field to produce sound.
• Electrostatic loudspeakers: Use a thin, electrically charged diaphragm placed between two conductive plates.
• Planar magnetic loudspeakers: Similar to electrostatic speakers but use a magnetic field instead of an electric field.
• Horn loudspeakers: Employ a horn to amplify the sound from a small diaphragm.
• Subwoofers: Designed specifically to reproduce low-pitched audio frequencies known as bass.

Applications

Loudspeakers are used in a wide range of applications, including sound reinforcement systems, public address systems, home audio systems, and car audio systems. They are also an essential component of home theaters, smartphones, and portable media players.

See Also

• Audio Signal
• Sound Reproduction
• Acoustics
• Speaker Wire

Loud-speaker Resources
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