RCA Photophone was the trade name given to one of four major competing technologies that emerged in the American film industry in the late 1920s for synchronizing electrically recorded audio to a motion picture image. RCA Photophone was an optical sound, "variable-area" film exposure system, in which the modulated area (width) corresponded to the waveform of the audio signal. The three other major technologies were the Warner Bros. Vitaphone sound-on-disc system, as well as two "variable-density" sound-on-film systems, Lee De Forest's Phonofilm, and Fox-Case's Movietone. When Joseph P. Kennedy and other investors merged Film Booking Offices of America (FBO) with the Keith-Albee-Orpheum theater chain and Radio Corporation of America; the resulting movie studio RKO Radio Pictures used RCA Photophone as its primary sound system. In March 1929, RKO released Syncopation, the first live-recorded film made with RCA Photophone. History and licensing In the early years following World War I, Charles A. Hoxie working at General Electric (GE) developed a photographic film recorder, initially to record transoceanic wireless telegraphy signals. However, this recorder was later adapted for recording speech and was used in 1921 to record speeches by President Calvin Coolidge and others which were broadcast over Station WGY (Schenectady). This recorder was called the Pallophotophone. In 1925, GE began a program to develop commercial sound-on-film equipment based on Hoxie's work. Unlike the Phonofilm and Movietone systems in which the audio modulated the intensity of a recording lamp which exposed the soundtrack, thus creating a variable-density track, the GE system employed a fast-acting mirror galvanometer to create a variable-area soundtrack. A number of demonstrations of this system, now known as Photophone, were given in 1926 and 1927. The first public screenings with this system were of a sound version (music plus sound effects only) of the silent film Wings which was exhibited as a road-show in around a dozen specially equipped theatres during 1927. In April 1928, RCA Photophone Inc. was created as a subsidiary of RCA (itself then a GE subsidiary) to commercially exploit the Photophone system. David Sarnoff was president and a member of the board of directors. The RCA system continued to use the galvanometer until the 1970s, when it became technically obsolete. The Western Electric system continued to use the light valve, and, under successor ownership, is still used to this day. For nearly half a century, motion picture sound systems were licensed, with two major licensors