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.
Sound film
A few innovative commercial directors immediately saw the ways in which sound could be employed as an integral part of cinematic storytelling, beyond the obvious function of recording speech. In "Blackmail", Hitchcock manipulated the reproduction of a character's monologue so the word "knife" would leap out from a blurry stream of sound, reflecting the subjective impression of the protagonist, who is desperate to conceal her involvement in a fatal stabbing. In his first film, the Paramount "Applause" (1929), Rouben Mamoulian created the illusion of acoustic depth by varying the volume of ambient sound in proportion to the distance of shots. At a certain point, Mamoulian wanted the audience to hear one character singing at the same time as another prays; according to the director, "They said we couldn't record the two things—the song and the prayer—on one mike and one channel. So I said to the sound man, 'Why not use two mikes and two channels and combine the two tracks in printing?'" Such methods would eventually become standard procedure in popular filmmaking.