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Phonofilm is an optical sound-on-film system developed by inventors Lee de Forest and Theodore Case in the early 1920s.

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trademark
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discoverer or inventor
Theodore Willard Case
Commons category
Phonofilm

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~42 min read

Encyclopedic overview

13 sections
Contents
  • Development
  • Debut
  • Hollywood chooses other sound systems
  • Downfall
  • Phonofilm in the UK
  • Phonofilm in Australia
  • Phonofilm in Spain
  • Phonofilm in Latin America
  • Legacy of Phonofilm
  • List of films produced in Phonofilm
  • See also
  • References
  • External links

Phonofilm is an optical sound-on-film system developed by inventors Lee de Forest and Theodore Case in the early 1920s.

In 1919 and 1920, de Forest, inventor of the audion tube, filed his first patents on a sound-on-film process, DeForest Phonofilm, which recorded sound directly onto film as parallel lines. These parallel lines photographically recorded electrical waveforms from a microphone, which were translated back into sound waves when the movie was projected.

Excerpted from Wikipedia’s “Phonofilm” article, available under the CC BY-SA 4.0 licence.

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