advertisement
WikiVisually
Infinite photos and videos for every Wiki article · Find something interesting to watch in seconds
Largest Palaces History by Country Celebrities Great Artists Great Cities Presidents Wars and Battles Famous Castles Supercars Rare Coins Orders and Medals Richest US Counties World Banknotes Largest Empires Sports Recovered Treasures Kings of France Ancient Marvels Animals Crown Jewels Countries of the World Best Campuses Great Museums Tallest Buildings Wonders of Nature British Monarchs
more top lists
History
Optical sound
Videos
Page
Optical sound is a means of storing sound recordings on transparent film. Originally developed for military purposes, the technology first saw widespread use in the 1920s as a sound-on-film format for motion pictures. Optical sound eventually superseded all other sound film technologies until the advent of digital sound became the standard in cinema projection booths. Optical sound has also been used for multitrack recording and for creating effects in some musical synthesizers.
Edge of a 35 mm film print showing four types of soundtrack. The stereo optical sound strip is located on the right, with waveforms for left and right
Edge of a 35 mm film print showing four types of soundtrack. The stereo optical sound strip is located on the right, with waveforms for left and right channels. To the far left is the SDDS digital track (blue area to the left of the sprocket holes), then the Dolby Digital (grey area between the sprocket holes labelled with the Dolby "Double-D" logo in the middle), and to the right of the analog optical sound is the DTS time code (the dashed line to the far right.)
A transparent program disc imprinted with concentric optical sound tracks, used for the Optigan musical organ
A transparent program disc imprinted with concentric optical sound tracks, used for the Optigan musical organ
Example of a variable-area sound track on the right side of the frames on this strip of 16mm film. The width of the white area is proportional to the
Example of a variable-area sound track on the right side of the frames on this strip of 16mm film. The width of the white area is proportional to the amplitude of the audio signal at each instant.
Newspaper ad for a 1925 presentation of De Forest Phonofilms shorts, touting their technological distinction: no phonograph.
Newspaper ad for a 1925 presentation of De Forest Phonofilms shorts, touting their technological distinction: no phonograph.
Sound-on-film
Videos
Page
Sound-on-film is a class of sound film processes where the sound accompanying a picture is recorded on photographic film, usually, but not always, the same strip of film carrying the picture. Sound-on-film processes can either record an analog sound track or digital sound track, and may record the signal either optically or magnetically. Earlier technologies were sound-on-disc, meaning the film's soundtrack would be on a separate phonograph record.
Edge of a 35mm film print showing the soundtracks. The outermost strip (left of picture) contains the SDDS track as an image of a digital signal; the
Edge of a 35mm film print showing the soundtracks. The outermost strip (left of picture) contains the SDDS track as an image of a digital signal; the next contains the perforations used to drive the film through the projector, with the Dolby Digital track (grey areas) with the Dolby Double-D logo, between them. The two tracks of the analog soundtrack on the next strip are bilateral variable-area, where amplitude is represented as a waveform. These are generally encoded using