Mickey Mouse
Audiences at the time of "Steamboat Willie"'s release were reportedly impressed by the use of sound for comedic purposes. Sound films or "talkies" were still considered innovative. The first feature-length movie with dialogue sequences, "The Jazz Singer" starring Al Jolson, was released on October 6, 1927. Within a year of its success, most United States movie theaters had installed sound film equipment. Walt Disney apparently intended to take advantage of this new trend and, arguably, managed to succeed. Most other cartoon studios were still producing silent products and so were unable to effectively act as competition to Disney. As a result, Mickey would soon become the most prominent animated character of the time. Walt Disney soon worked on adding sound to both "Plane Crazy" and "The Gallopin' Gaucho" (which had originally been silent releases) and their new release added to Mickey's success and popularity. A fourth Mickey short, "The Barn Dance", was also put into production; however, Mickey does not actually speak until "The Karnival Kid" in 1929 when his first spoken words were "Hot dogs, Hot dogs!" After "Steamboat Willie" was released, Mickey became a close competitor to Felix the Cat, and his popularity would grow as he was continuously featured in sound cartoons. By 1929, Felix would lose popularity among theater audiences, and Pat Sullivan decided to produce all future Felix cartoons in sound as a result. Unfortunately, audiences did not respond well to Felix's transition to sound and by 1930, Felix had faded from the screen.
Foley (filmmaking)
What is now called Foley originated as sound effects added to live broadcasts of radio drama from radio studios around the world in the early 1920s. Phonograph recordings of the era were not of sufficient quality or flexibility to faithfully reproduce most sound effects on cue, so a sound effects person had to create all sounds for radio plays live. Jack Donovan Foley started working with Universal Studios in 1914 during the silent movie era. When Warner studios released "The Jazz Singer", its first film to include sound, Universal knew it needed to stay competitive and called for any employees who had radio experience to come forward. Foley became part of the sound crew that turned Universal's then-upcoming "silent" musical "Show Boat" into a musical. Because microphones of the time could not pick up more than dialogue, other sounds had to be added in after the film was shot. Foley and his small crew projected the film on a screen while recording a single track of audio that captured their live sound effects. Their timing had to be perfect, so that footsteps and closing doors synchronized with the actors' motions in the film. Jack Foley created sounds for films until his death in 1967. His basic methods are still used today.