Development of sound technology in Hollywood in the 1920s

When sound film was introduced in the late 1920s, a constant speed was required for the sound head; 24 frames per second were chosen because it was the slowest speed which meant is was the cheapest which allowed for sufficient sound quality.

In 1922, Tri-Ergon announced the development of a glow lamp light modulator for variable density recording of sound. The Tri Ergon process had a patterned flywheel mechanism on a sprocket which prevented variations in film speed.  This flywheel helped prevent distortion of the audio.

The Vitaphone was a sound-on-disc system using multiple 33 1/3 rpm discs.  The Vitaphone system was first embraced by Warner Brothers.  In August 1926, Warner Brothers introduced the first Vitaphone film Don Juan.   Don Juan was the first mainstream film that replaced the traditional use of a live orchestra or organ for the soundtrack. However, in Don Juan there was no dialogue in the film.

The first movie with dialogue was ‘The Jazz Singer’ although originally conceived as a singing picture with no dialogue; Al Jolson ad-libbed some dialogue on the set.  In 1928, Lights of New York was released by Warner Brothers as the first all-dialogue film.

Later in 1928, Disney's ‘Steamboat Willie’ premiered.  It was the first film to completely create a soundtrack in post production including sound effects, music, and dialogue.