Loudspeaker

A loudspeaker, or simply speaker, is an electromechanical device which converts an electrical signal into sound. The term is used to refer to both the transducer, or driver itself, and a complete system consisting of one or more transducers in an enclosure. The loudspeaker is the most variable element in an audio system. The audible differences between speaker systems are considerable.

History

Nikola Tesla is believed to have put electrically charged carbon dust in a cup-shaped device to create the first telephone loudspeaker. However, the first documented http://www.tfcbooks.com/teslafaq/q&a_040.htm device that might fit this description was created in 1881.

Related Topics:
Nikola Tesla - Telephone - 1881

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Alexander Bell patented the first loudspeaker as part of his telephone in 1876. This was soon followed by an improved version from Ernst Siemens in Germany and England (1878). The modern design of moving-coil loudspeaker was established by Oliver Lodge in England (1898). http://history.acusd.edu/gen/recording/loudspeaker.html

Related Topics:
Alexander Bell - 1876 - Ernst Siemens - 1878 - Oliver Lodge - 1898

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Since large powerful permanent magnets of the correct shape for loudspeaker construction were not freely available at reasonable cost, the original loudspeakers of modern design, found in early radio systems such as the Atwater Kent for instance, utilized electromagnets, energized through a second pair of terminals (which sometimes confuses those unfamiliar with this bit of history). This winding usually served a dual role, acting as a choke coil in the power supply filter section; therefore if such a loudspeaker is replaced with a modern permanent magnet design, a suitable choke coil must also replace it in the power supply.

Related Topics:
Permanent magnet - Radio - Atwater Kent - Electromagnet - Choke coil - Power supply - Filter

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The quality of loudspeaker systems until the 1950s was, to modern ears, very poor. Developments in cabinet technology (e.g. acoustic suspension) and changes in materials used in the actual loudspeaker, such as the move away from simple paper cones, led to audible improvements. Paper cones (or doped paper cones, where the paper is treated with a substance to improve its performance) are still in use today, and can provide good performance. Polypropylene and aluminium are also used as diaphram materials.

Related Topics:
1950s - Polypropylene - Aluminium

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