The cartoon was not the first cartoon to feature a soundtrack connected to the action. Fleischer Studios, headed by brothers Dave and Max Fleischer, had already released a number of sound cartoons using the DeForest system in the mid-1920s. However, these cartoons did not keep the sound synchronized throughout the film. For "Willie", Disney had the sound recorded with a click track that kept the musicians on the beat. This precise timing is apparent during the "Turkey in the Straw" sequence when Mickey's actions exactly match the accompanying instruments. Animation historians have long debated who had served as the composer for the film's original music. This role has been variously attributed to Wilfred Jackson, Carl Stalling and Bert Lewis, but identification remains uncertain. Walt Disney himself was voice actor for both Mickey and Minnie and would remain the source of Mickey's voice through 1946 for theatrical cartoons. Jimmy MacDonald took over the role in 1946, but Walt provided Mickey's voice again from 1955 to 1959 for "The Mickey Mouse Club" television series on ABC.