Classical Hollywood cinema
The beginning of the sound era itself is ambiguously defined. To some, it began with "The Jazz Singer", which was released in 1927 and increased box-office profits for films, as sound was introduced to feature films. To others, the era began in 1929, when the silent age had definitively ended. Most Hollywood pictures from the late 1920s to 1960s adhered closely to a genre—Western, slapstick comedy, musical, animated cartoon, and biopic (biographical picture)—and the same creative teams often worked on films made by the same studio. For instance, Cedric Gibbons and Herbert Stothart always worked on MGM films; Alfred Newman worked at Twentieth Century Fox for twenty years; Cecil B. DeMille's films were almost all made at Paramount Pictures; and director Henry King's films were mostly made for Twentieth Century Fox. Similarly, actors were mostly contract players. Film historians and critics note that it took about a decade for films to adapt to sound and return to the level of artistic quality of the silents, which it did in the late 1930s.
Stereophonic sound
Bell Laboratories gave a demonstration of three-channel stereophonic sound on April 27, 1933, with a live transmission of the Philadelphia Orchestra from Philadelphia to Constitution Hall in Washington, D.C. over multiple Class A telephone lines. Leopold Stokowski, normally the orchestra's conductor, was present in Constitution Hall to control the sound mix. Five years later, the same system would be expanded onto multi-channel film recording and used from the concert hall in Philadelphia to the recording labs at Bell Labs in New Jersey in order to record Walt Disney's "Fantasia" (1940) in what Disney called Fantasound.
Later that same year, Bell Labs also demonstrated binaural sound, at the Chicago World's Fair in 1933 using a dummy with microphones instead of ears, . The two signals were sent out over separate AM station bands.