History of the speaker

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The history of the loudspeaker begins in 1861 as a purely mechanical construction that was created as a by-product of telephone development.

Historical magnetic loudspeaker from Celestion from 1924
Loudspeaker as an art object

The patent for the first electric loudspeaker was granted in 1878, but was not presented to the public until 1925. As a result, the efficiency, size and fidelity were optimized, whereby the basic principle of the electrodynamic loudspeaker remained unchanged, which is still used today for 90% of loudspeakers.

Electrodynamic loudspeaker

Development of the telephone as the starting signal

The invention of the speaker was directly related to the development of the telephone. As a result, the loudspeaker, like the telephone, does not have a direct inventor but rather several ancestors.

In 1860 Antonio Meucci demonstrated a telephone connection invented for himself and his sick wife.

On October 26, 1861, elementary school teacher Philipp Reis presented the telephone he had invented to the Physikalischer Verein in Frankfurt. But he did not succeed in conveying the significance of his invention to those around him. In 1870 Thomas Alva Edison carried out the first experiments with his phonograph . Based on the inventions of Reis and Meucci, Alexander Graham Bell further developed the telephone until it was ready for the market. The invention of the sound transducer thus took place on the side, so to speak.

Refinement of the principle

Werner von Siemens received a patent in 1878 for the electrodynamic loudspeaker, which is still in use today. This construction was already very mature, with fixed (horseshoe) magnet, moving voice coil and moving NAWI- membrane (NAWI stands for n maybe a b wi ckelbar). His bad luck was the lack of suitable amplifiers . The founder of modern loudspeakers in England is considered to be the physics professor Sir Oliver Lodge , who teaches at the University of Birmingham . The primitive electromagnetic loudspeaker with a fixed coil and movable iron core was not yet suitable for the reproduction of sounds that is true to nature in today's sense .

Market readiness

27 years later, the first radio exhibition in Berlin in 1925 presented the Blatthaller, the first electrodynamic loudspeaker, a construction a good meter long that had a fixed magnet system and a movable current-carrying conductor. In the same year Edward Kellog and Chester Rice from the American company Western Electric developed the electrodynamic loudspeaker, as it is in principle still installed in well over 90 percent of all loudspeaker systems today. It has a moving voice coil that is connected to a conical membrane and repels itself from the surrounding magnetic field in time with the current flowing through it. Since there were no powerful amplifiers, the loudspeaker efficiency had to be extremely high, which resulted in very large horns for amplification. With the cinema and hall sound system for which these horn loudspeakers were used, the enormous dimensions were no problem.

A technical problem remained: permanent magnets with sufficient force ( magnetic induction or magnetic flux ) did not yet exist at the beginning of the 20th century, which is why electromagnets generated the required magnetic field at that time. The Englishman of German descent Paul GAH Voigt is one of the pioneers of loudspeakers with permanent magnets; after he worked with his company Lowther Voigt Ltd., founded in 1927 . initially produced sound transducers with an “energized magnet”, in 1936 he presented the first prototype of a loudspeaker with a “permanent magnet”.

Modern speakers

The era of the modern loudspeaker begins with the work of the Australian Albert Neville Thiele and the American Richard H. Small , who from 1951 put the interactions between the loudspeaker and its housing on a theoretically sound basis ( Thiele-Small parameters) and the Developed the prerequisites for relatively small loudspeaker boxes to be able to emit astonishingly low frequencies today . So it is not surprising that the majority of loudspeaker manufacturers active today were only founded in the sixties and early seventies.

The contributions by Thiele and Small, which are essential for the analysis and simulation of direct radiating loudspeakers, were preceded by numerous theoretical treatises on acoustic elements, of which Harry F. Olson's Elements of Acoustical Engineering (1940) should be mentioned in particular .

Henry Kloss made history in loudspeaker construction as he completed the suspension of the membrane.

Recent developments

More recent developments show a generally different generation of loudspeakers. In 1978, Jon Dahlquist, with the support of Saul B. Marantz, founded the Dahlquist company, which presented the first loudspeakers without housing and simulation of surfaces from an in-phase array of transducers. Stanley Marquiss - who founded ESS - went further and presented the first truly flat wall-mounted loudspeaker in 1983.

In 1993 the distributed mode loudspeaker developed by Ken Heron was created, which specifically uses partial vibrations to generate sound.

Directional loudspeakers were used until 2007 only as special loudspeakers with strong directional characteristics for the targeted sound reinforcement of defined listening areas. It was therefore only used in rooms that were acoustically unsuitable for speech reproduction or in environments with simultaneous microphone operation in order to minimize feedback based on a wall core with cardioid characteristics. Tony Hooley of 1, Ltd. In 2007 he used several piezo-based converters as directional loudspeakers in his sound projectors to construct a surround system out of a box.

Elwood G. Norris used directional loudspeakers in ultrasonic technology in 1996 to create flat loudspeakers. Hearing frequencies are modulated onto the ultrasound. As a result of the non-linear properties of the air, these strongly bundled frequencies can be heard again at some distance. With the HSS system, smooth surfaces are specifically used to demodulate the sound and fan it out again into the room.

Another special form is wave field synthesis . In contrast to classic two-channel and multi-channel stereophony, the attempt is not only made to reproduce the sound impression in a limited space (hot spot), but also to generate the original wavefront. This creates an authentic sound in large areas of the entire listening room.

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  1. http://www.medienstimmen.de/ela/lexikon/nawimembran.htm