Vivid Audio GIYA Owner's Manual page 19

EARLY BELL LOUDSPEAkERS
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.
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.
1925 - Grebe radio receiver and 1924 Western electric 540 speaker (NmAh)
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
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.
ChAPter 6 17