Vivid Audio GIYA Owner's Manual page 20

VITAPHONE 555-W, FROm AT&T ARCHIVES
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.
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 . these "directional
baffle" horns had an opening 3 ft. by 4 ft. and were different from small-throat horns.
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