Theodore Case Sound Test: Gus Visser and his Singing Duck (1925), also known as Gus Visser and His Singing Duck, is an early sound film, directed by Theodore Case while perfecting his variable density sound-on-film process. Case began working on his sound film process at the Case Research Lab in Auburn, New York in 1921. There are as many as three separate takes of Mr. Visser's act that exist. The film was shown in June 1925 at the Exposition of Progress in Auburn.
From 1921 to 1924, Case provided Lee De Forest with inventions of the Case Research Lab for use as improvements in De Forest's Phonofilm system, but had a falling out with De Forest after failing to be credited for those inventions, such as the AEO Light, that made De Forest's system workable. From 1916 to 1927, Earl I. Sponable worked for Case. After Case sold his system in July 1926 to William Fox-- who renamed the Case system Fox Movietone -- Sponable went to work for Fox Movietone.