page_title: Movietone sound system
section_title: Later development
hierarchical_section_title: Movietone sound system / Later development
caption_attribution_description: The Fox Mo folm vietone
context_page_description: The Movietone sound system is an optical sound-on-film method of recording sound for motion pictures that guarantees synchronization between sound and picture. It achieves this by recording the sound as a variable-density optical track on the same strip of film that records the pictures. The initial version was capable of a frequency response of 8500 Hz. Although sound films today use variable-area tracks, any modern motion picture theater can play a Movietone film without modification to the projector. Movietone was one of four motion picture sound systems under development in the U.S. during the 1920s, the others being DeForest Phonofilm, Warner Brothers' Vitaphone, and RCA Photophone, though Phonofilm was primarily an early version of Movietone.
context_section_description: The Case Research Lab sound system influenced many industry standards, such as location of the optical sound 20 frames in advance of the image it accompanies.  The current SMPTE standard for 35 mm sound film is +21 frames for optical, but a 46-foot theatre reduces this to +20 frames; this was originally done partly to ensure the film runs smoothly past the sound head, but also to ensure that no Phonofilm could again be played in theaters — the Phonofilm system being incompatible with Case Research Lab specifications — and also to ease the modification of projectors already widely in use.
  Sponable worked at the Fox Film Corporation (later 20th Century Fox) Movietone studios on 54th Street and 10th Avenue in New York City until he retired in the 1960s, eventually winning an Academy Award for his technical work on the development of CinemaScope. Sponable had many contributions to film technology during his career, including the invention of the perforated motion-picture screen that allowed placing the speakers behind it to enhance the illusion of the sound emanating directly from the film action. During his years at Fox, Sponable also served for a time as an officer of the Society of Motion Picture and Television Engineers. He published a concise history of sound film in the April 1947 issue of The SMPE Journal (The SMPTE Journal after 1950).
  The history of Case Research Lab has long been unheralded for numerous reasons. Theodore Case died in 1944, after donating his home and laboratory to be preserved as a museum to the inventions of Case Research Lab. The museum's first director, who oversaw the museum for 50 years, put the laboratory's contents into storage and converted the building into an art studio. The Case Research Lab sound studio was located on the second floor of the estate's carriage house and that was rented to the local model train club until the early 1990s.
  Fox was seriously injured in a July 1929 car accident, lost his company in 1930 when his loans were called in and lost the 1936 lawsuit in the U.S. Supreme Court against the film industry for violating the Tri-Ergon patents he owned. Sponable did little to establish the record of Case Research Lab inventions, other than his April 1947 article in The Journal of the SMPE.
  Incredibly, it was also in 1947 that the Davis Loop Drive was first introduced to Western Electric licensees, including Twentieth Century-Fox (WECo RA-1231; and still made to this day by a successor company).
  Recently, Case Research Lab, the adjoining carriage house, and Case's home have been restored and research is ongoing with the collections of the lab that include all receipts, notebooks, correspondence, and much of the laboratory's original equipment, including the first recording device created to test the AEO light. In the collections are also letters from Thomas Edison, an original copy of the Tri-Ergon patents, and an internal document from Fox Films written in the 1930s. This latter document says that once it became public knowledge that Sponable perfected the variable-area system of sound-on-film at the Fox Studios, that system became the standard and replaced the inventions of Case Research Lab.
  A number of films owned by Case Research Lab and Museum and restored by George Eastman House in Rochester, New York, are in the collections of both of those institutions. The Case Research Lab and Museum has additional sound-film footage of Theodore Case, and recently discovered copies of the same films at the Eastman House, are in a much higher state of preservation. Movietone News films are in the collections of 20th-Century Fox and the University of South Carolina at Columbia, including the only known footage of Earl I. Sponable talking. Sponable can also be seen in footage of the premiere of the film The Robe.
  Phonofilms that were produced using Case Research Lab inventions are in the collections of the Library of Congress and the British Film Institute.
  Variable density (VD) recording systems developed from Movietone gradually lost market share to variable area (VA) ones develope
caption: A vintage Fox movietone motion picture camera
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