Vivid Audio V1w - Manual (Page 10)

1921 - The Phonetron based on patent No. 1,847,935 filed
Apr. 23, 1921, by C. L. Farrand, was the first coil-driven
direct-radiator loudspeaker to be sold in the U.S. and was
well-received, competing with the horns used by table
radios
1925 Grebe radio
receiver and 1924
Western Electric 540
speaker (NMAH)
1923 - The Thorophone was a gooseneck loudspeaker
with a voice-coil driver
1925 - The research paper of Chester W. Rice and
Edward W. Kellogg at General Electric was important in
establishing the basic principle of the direct-radiator
loudspeaker with a small coil-driven mass-controlled
diaphragm in a baffle with a broad midfrequency range of
uniform response. Edward Wente at Bell Labs had
independently discovered this same principle, filed patent
No. 1,812,389 Apr. 1, 1925, granted June 30, 1931. The
Rice-Kellogg paper also published an amplifier design that
was important in boosting the power transmitted to
loudspeakers. In 1926, RCA used this design in the
Radiola line of a.c. powered radios.
1925 - Victor Orthophonic acoustic phonograph player had a folded exponential horn
that was later used as model for the Klipsch speaker of the hi-fi era. Within a year,
the Orthophonic faced competition from all-electric phonographs with an
electromechanical pickup, vacuum-tube amplifier, and moving-coil loudspeaker, such
as the Brunswick Panatrope sold by the Brunswick-Balke-
Collender Company.
1926 - Vitaphone sound system for motion pictures used a
new speaker developed at Bell Labs. Wente and Thuras
designed the Western Electric 555-W speaker driver that
was coupled with a horn having a 1-in. throat and a 40-sq.
ft. mouth; it was capable of 100-5000 hz freq. range with
an efficiency of 25% (compared to 1% today) needed due
to low amp power of 10 watts. The power amps were 205-
D. Older loudspeakers were balanced armature type, but
the newer 555-W speakers of the Vitaphone were moving
coil type.
1928 - Herman J. Fanger filed patent No. 1,895,071 on
Sep. 25, 1928, granted Jan. 24, 1933, that described what
came to be known as the coaxial speaker, composed of a
small high frequency horn with its own diaphragm nested
inside or in front of a large cone loudspeaker, based on
the variable-area principle that made the center cone light and stiff for high
frequencies and the outer cone flexible and highly damped for lower frequencies.
Vitaphone 555-W, from
AT&T Archives
1929 - E. W. Kellogg filed patent No. 1,983,377 on September 17, 1929, granted
December 4, 1934, that described an electrostatic speaker composed of many small
sections able to radiate sound with out magnets or cones or baffles. This patent, as
well as the 1932 British patents of Hans Vogt, influenced Peter Walker to build the
Quad ESL flat panel speaker in 1957.
1929 - J. D. Seabert of Westinghouse developed a horn-type loudspeaker that
directed the sounds of human speech toward the audience better than cone
speakers that were intended for the over-all sound including music to fill the entire
theatre. These "directional baffle" horns had an opening 3 ft. by 4 ft. and were
different from small-throat horns.
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