Sound-on-film
Encyclopedia
Sound film
A sound film is a motion picture with synchronized sound, or sound technologically coupled to image, as opposed to a silent film. The first known public exhibition of projected sound films took place in Paris in 1900, but decades would pass before sound motion pictures were made commercially...
processes where the sound accompanying picture is physically recorded onto photographic film, usually, but not always, the same strip of film carrying the picture. Sound-on-film processes can either record an analog
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
sound track or digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
sound track, and may record the signal either optically
Optics
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...
or magnetically
Magnetism
Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...
. Earlier technologies were sound-on-disc
Sound-on-disc
The term Sound-on-disc refers to a class of sound film processes using a phonograph or other disc to record or playback sound in sync with a motion picture...
, meaning the film's soundtrack would be on a separate phonograph record.
Although Al Jolson's
Al Jolson
Al Jolson was an American singer, comedian and actor. In his heyday, he was dubbed "The World's Greatest Entertainer"....
The Jazz Singer
The Jazz Singer (1927 film)
The Jazz Singer is a 1927 American musical film. The first feature-length motion picture with synchronized dialogue sequences, its release heralded the commercial ascendance of the "talkies" and the decline of the silent film era. Produced by Warner Bros. with its Vitaphone sound-on-disc system,...
was far from being the first film with a synchronised soundtrack, it was the first feature length film with lip-sync dialogue. It achieved significant commercial success and thus provided the impetus for the rapid switch to sound film production in Hollywood.
Analog sound-on-film recording
The most prevalent modern method of recording sound on a film print is by stereo variable-area (SVA) recording, encoding a two-channel audio signal as a pair of lines running parallel with the film's direction of travel through the projector. The lines change area (grow broader or narrower) depending on the magnitude of the signal. The projector shines a light or LEDLight-emitting diode
A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting...
, called an exciter, through a perpendicular slit onto the film. The image on the small slice of exposed track modulates the intensity of the light, which is collected by a photosensitive element, a photodiode
Photodiode
A photodiode is a type of photodetector capable of converting light into either current or voltage, depending upon the mode of operation.The common, traditional solar cell used to generateelectric solar power is a large area photodiode....
or CCD
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
.
Commonly, the audio signal recorded onto an SVA track is encoded through a phase matrix
Matrix decoder
Matrix decoder is an audio technology where a finite number of discrete audio channels are decoded into a larger number of channels on play back...
, which allowed the two-channel format to record a center and surround channel, and companding noise reduction
Companding
In telecommunication, signal processing, and thermodynamics, companding is a method of mitigating the detrimental effects of a channel with limited dynamic range...
, which allows a constant signal-to-noise ratio
Signal-to-noise ratio
Signal-to-noise ratio is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined as the ratio of signal power to the noise power. A ratio higher than 1:1 indicates more signal than noise...
to be delivered over a wide dynamic range.
Earlier processes, used on 70mm film
70 mm film
70mm film is a wide high-resolution film gauge, with higher resolution than standard 35mm motion picture film format. As used in camera, the film is wide. For projection, the original 65mm film is printed on film. The additional 5mm are for magnetic strips holding four of the six tracks of sound...
prints and special presentations of 35mm film
35 mm film
35 mm film is the film gauge most commonly used for chemical still photography and motion pictures. The name of the gauge refers to the width of the photographic film, which consists of strips 35 millimeters in width...
prints, recorded sound magnetically on ferric oxide
Iron(III) oxide
Iron oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron oxide , which is rare, and iron oxide , which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the main...
tracks bonded to the film print, outside the sprocket holes.
Sound-on-film formats
Almost all modern motion picture sound formats are sound-on-film formats, including:Optical analog formats
- Fox/Western ElectricWestern ElectricWestern Electric Company was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. It was the scene of a number of technological innovations and also some seminal developments in industrial management...
(Westrex) MovietoneMovietone sound systemThe Movietone sound system is a 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...
, are variable-density formats of sound filmSound filmA sound film is a motion picture with synchronized sound, or sound technologically coupled to image, as opposed to a silent film. The first known public exhibition of projected sound films took place in Paris in 1900, but decades would pass before sound motion pictures were made commercially...
. (No longer used, but still playable on modern projectors.) - RCA PhotophoneRCA PhotophoneRCA Photophone was the trade name given to one of four major competing technologies that emerged in the American film industry in the late 1920s for synchronizing electrically recorded audio to a motion picture image. RCA Photophone was a sound-on-film, "variable-area" film exposure system, in...
, a variable-area format now universally used for optical analog soundtracks - since the late 1970s, usually with a Dolby encoding matrix.
Obsolete formats
- FantasoundFantasoundFantasound was a stereophonic sound reproduction system developed by the engineers of Walt Disney studios for its 1940 animated film Fantasia, the first commercial film to be released in stereo. Fantasound led to the development of what is known today as surround sound.-Origins:Walt Disney's...
, where sound and picture were recorded on separate strips of film, introduced for initial release of DisneyWalt DisneyWalter Elias "Walt" Disney was an American film producer, director, screenwriter, voice actor, animator, entrepreneur, entertainer, international icon, and philanthropist, well-known for his influence in the field of entertainment during the 20th century. Along with his brother Roy O...
's FantasiaFantasia (film)Fantasia is a 1940 American animated film produced by Walt Disney and released by Walt Disney Productions. The third feature in the Walt Disney Animated Classics series, the film consists of eight animated segments set to pieces of classical music conducted by Leopold Stokowski, seven of which are...
(1940) - PhonofilmPhonofilmIn 1919, Lee De Forest, inventor of the audion tube, filed his first patent 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...
, patented by Lee De ForestLee De ForestLee De Forest was an American inventor with over 180 patents to his credit. De Forest invented the Audion, a vacuum tube that takes relatively weak electrical signals and amplifies them. De Forest is one of the fathers of the "electronic age", as the Audion helped to usher in the widespread use...
in 1919, defunct by 1929 - Cinema Digital SoundCinema Digital SoundCinema Digital Sound is a multi-channel surround sound format used for theatrical films in the early 1990s. The system was developed by Eastman Kodak and Optical Radiation Corporation. CDS was quickly superseded by Digital Theatre System and Dolby Digital formats.CDS format replaced the analogue...
, an optical format which was the first commercial digital sound format, used between 1990 and 1992
Further reading
- MovietoneMovietone sound systemThe Movietone sound system is a 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...
- Sound filmSound filmA sound film is a motion picture with synchronized sound, or sound technologically coupled to image, as opposed to a silent film. The first known public exhibition of projected sound films took place in Paris in 1900, but decades would pass before sound motion pictures were made commercially...
- VitaphoneVitaphoneVitaphone was a sound film process used on feature films and nearly 1,000 short subjects produced by Warner Bros. and its sister studio First National from 1926 to 1930. Vitaphone was the last, but most successful, of the sound-on-disc processes...
- RCA PhotophoneRCA PhotophoneRCA Photophone was the trade name given to one of four major competing technologies that emerged in the American film industry in the late 1920s for synchronizing electrically recorded audio to a motion picture image. RCA Photophone was a sound-on-film, "variable-area" film exposure system, in...
- PhonofilmPhonofilmIn 1919, Lee De Forest, inventor of the audion tube, filed his first patent 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...
- PhotokinemaPhotokinemaPhoto-Kinema was a sound-on-disc system for motion pictures invented by Orlando Kellum.-1921 introduction:The system was first used for a small number of short films, mostly made in 1921...
- sound-on-discSound-on-discThe term Sound-on-disc refers to a class of sound film processes using a phonograph or other disc to record or playback sound in sync with a motion picture...
- List of film formats
- Joseph Tykociński-Tykociner
- List of film sound systems
- Multichannel Film Sound (MKPE)