Vivid Audio V1w - Manual (Page 9)

9
Some early loudspeaker history
1874 - Ernst W. Siemens was the first to describe the "dynamic" or moving-coil
transducer, with a circular coil of wire in a magnetic field and supported so that it
could move axially. He filed his U. S. patent application for a "magneto-electric
apparatus" for "obtaining the mechanical movement of an electrical coil from
electrical currents transmitted through it" on Jan. 20, 1874, and was granted patent
No. 149,797 Apr. 14, 1874. However, he did not use his device for audible
transmission, as did Alexander G. Bell who patented the telephone in 1876. After
Bell's patent was granted, Siemens applied for German patent No. 2355, filed Dec.
14, 1877, for a nonmagnetic parchment diaphragm as the sound radiator of a
moving-coil transducer. The diaphragm could take the form of a cone, with an
exponentially flaring "morning glory" trumpet form. This is the first patent for the
loudspeaker horn that would be used on most phonographs players in the acoustic
era. His German patent was granted July 30, 1878 and his British patent No. 4685
was granted Feb. 1, 1878.
1898 - Oliver Lodge filed for British patent No. 9712 on
Apr. 27, 1898, for an improved loudspeaker with
nonmagnetic spacers to keep the air gap between the
inner and outer poles of a moving coil transducer. This
was the same year he applied for a patent on his famous
radio tuner. A model of his loudspeaker is in the British
Science Museum in South Kensington, and a photo was
published in Wireless World Dec. 21, 1927. This
improvement was later claimed by Pridham and Jensen in
the Magnavox application for patent No. 1,448,279 filed
Apr. 28, 1920, and granted Mar. 13, 1923.
Oliver Lodge
from Das Fotoarchiv
1901 - John Stroh first described the conical paper diaphragm that terminated at the
rim of the speaker in a section that was flat except for corrugations, filed for the
British patent No. 3393 on Feb. 16, 1901, granted Dec. 14, 1901.
1908 - Anton Pollak improved the moving-coil loudspeaker with a voice-coil centering
spider, filed for U.S. patent No. 939,625 on Aug. 7, 1908, granted Nov. 9, 1909.
1911 - Edwin S. Pridham and Peter L. Jensen in Napa, California, invented a
moving-coil loudspeaker they called the "Magnavox" that was used by Woodrow
Wilson in San Diego in 1919.
1915 - Harold Arnold began program at Bell Labs to
improve phonographic sound recording. The first priority
was the electronic amplifier using the new vacuum tube,
second was the microphone, and third was the
loudspeaker that would improve the "balanced armature"
units developed for public address. After WWI, J. P.
Maxfield led this project that produced E. C. Wente's
moving coil speaker by 1925, the Orthophonic
phonographic player by 1925, and Vitaphone talking
motion pictures by 1926.
early Bell loudspeakers
1918 - Henry Egerton on 1918/01/08 filed patent for balanced-armature loudspeaker,
used in the Bell Labs No. 540AW speakers developed by N. H. Ricker Oct. 6, 1922,
that became the 540 commercial speaker by 1924; was based on the balanced
armature telephone patent of Thomas Watson granted Oct. 24, 1882, similar to
devices also developed by Siemens and Frank Capps.