In the early years following World War I, Charles A. Hoxie working at General Electric (GE) developed a photographic film recorder, initially to record transoceanic wireless telegraphy signals. However, this recorder was later adapted for recording speech and was used in 1921 to record speeches by President Calvin Coolidge and others which were broadcast over Station WGY (Schenectady). This recorder was called the Pallophotophone.
In 1925, GE began a program to develop commercial sound-on-film equipment based on Hoxie's work. Unlike the Phonofilm and Movietone systems in which the audio modulated the intensity of a recording lamp which exposed the soundtrack, thus creating a variable-density track, the GE system employed a fast-acting mirror galvanometer to create a variable-area soundtrack. A number of demonstrations of this system, now known as Photophone, were given in 1926 and 1927. The first public screenings with this system were of a sound version (music plus sound effects only) of the silent film Wings which was exhibited as a road-show in around a dozen specially equipped theatres during 1927.[1]
Magazine ad insert introducing RCA Photophone, 1928
In April 1928, RCA Photophone Inc. was created as a subsidiary of RCA (itself then a GE subsidiary) to commercially exploit the Photophone system. David Sarnoff was president and a member of the board of directors. The RCA system continued to use the galvanometer until the 1970s, when it became technically obsolete. The Western Electric system continued to use the light valve, and, under successor ownership, is still used to this day.
For nearly half a century, motion picture sound systems were licensed, with two major licensors in North America, RCA and Western Electric (Northern Electric, in Canada), which licensed their principal sound element (original track negative) recording systems on a non-exclusive basis. In general, motion picture producers elected to license one or the other. In a few cases, where mergers had occurred, a producer might be licensed for both. For many years, it was customary to "brand" a film with its sound system, variously as "RCA Sound Recording", "Western Electric Recording", or similar brands, often including the corporate logo of the licensor (Meatball for RCA; The Voice of Action for Western Electric; Li Westrex for the post-1956 divestiture of Western Electric under Litton Industries' ownership). Such branding ceased in about 1976, particularly after nearly all optical sound recording (for release prints) had been converted to Westrex's stereo variable-area system from RCA's and Westrex's mono systems, although there were a few examples of such branding thereafter (mainly Westrex.)
Many years later, the Photophone trademark would be reused by the Western Electric/Westrex stereo variable-area system, after both the Western Electric and Westrex trademarks became unavailable due to corporate asset sales by the disintegrating Bell System, but the Western Electric/Westrex stereo variable-area system continued to be marketed by a successor, and it is still serviced and supported to this day, although it is no longer branded as Photophone.
Comparison of (mono) variable-area and variable-density
Although variable-density sound system recording is usually associated with Western Electric and variable-area sound system recording is usually associated with RCA, these relationships are not cast into stone.
Both variable-area systems and variable-density systems were marketed by both RCA and Western Electric, the Western Electric light valve being capable of producing either variable-density or variable-area depending on which ribbon axis was parallel to the film motion, and the RCA galvanometer was capable of producing either variable-area or variable-density depending upon the particulars of the optical system.[2]
Roughly equal measured and perceived quality was available from both systems and from both manufacturers. Neither recording system nor manufacturer was clearly superior to the other, except where specific customer end-to-end processes made one system/manufacturer more consistently superior to the other system/manufacturer.
Variable-density was preferred for Technicolor sound prints as this process utilized a silver gray-scale "key" record, thereby creating a CMYK color image, and the soundtrack was also a silver gray-scale record, which greatly facilitated variable-density (and made variable-area rather difficult). The "key" record was deleted from most Technicolor prints after 1944, thereby creating a CMY color image, but Technicolor's strong preference for variable-density continued long thereafter.
Variable-density was finally abandoned as customer preferences for "dual-bilateral" variable-area soundtracks emerged in the late 1950s. This required changes to some laboratory processing and quality controls, but the real reason for variable-density's demise was yet to come.
Stereo variable-area
In the early-1970s, there was renewed interest in improving the quality of optical film soundtracks.
As a consequence by the early 1970s several individuals and organizations were considering improvements to the dated technical standards used for optical sound on 35mm film. In particular both Dolby Laboratories[3] and Kodak[4] were investigating the use of Dolby noise reduction on optical soundtracks.
In the mid-1970s, Westrex Corp. (a wholly owned subsidiary of Litton Industries since 1956, and the successor to Western Electric's cinema sound business unit) re-introduced the ca. 1938 "four ribbon" light valve, and the ca. 1947 RA-1231 sound recorder.[5]
When originally introduced in 1947, the RA-1231 could be configured as a mono 35mm variable-density or variable-area recorder, or a mono 16mm variable-density or variable-area recorder, at the customer's option. However its basic electro-optical arrangement could also be used to create a time-aligned, two-channel variable-area version,[6] and this then became the industry standard device for recording stereo variable-area optical soundtracks.
Variable-density's fate was then sealed as these stereo optical sound prints (as contrasted with stereo magnetic sound prints or mono optical sound prints) became a marketing imperative.
When encoded utilizing Dolby Laboratories' technology (itself originally being in part licensed from Sansui), the discrete L and R channels of Westrex's stereo variable-area system were renamed "Left Total" and "Right Total", and when decoded utilizing Dolby's Cinema Processor these produced the L, C, R and S sound image first commonly used by Fox's CinemaScope magnetic stereo system in 1953.
Stereo optical sound prints are compatible with films with any aspect ratio and with normal print film stocks with KS-type film perforations, whereas stereo magnetic sound prints require film stocks with the narrower CS-type film perforations. Film with CS-type perforations can only be run on a projector fitted with special narrow-toothed sprockets or permanent damage will be done to the film. An alternative is LaVezzi's VKF ("Very Kind to Film") sprockets, which perform optimally on KS- as well as CS-perforated prints. Stereo variable-area, therefore, provided for the first time stereo film prints of any aspect ratio (1.37:1/Academy through 2.35:1/CinemaScope, inclusive) which could be run without damage on any normal 35mm cinema projector.
Nearly all original track negatives (OTNs) are now produced as stereo variable-area, and the former Western Electric (Westrex) system has been renamed Photophone and has become the de facto standard for analogue optical soundtracks, world-wide.
The fully implemented case of stereo variable-area (i.e., 4-2-4 encoding/decoding) produces a stereo 3.1 track.
The partially degenerate case of stereo variable-area (i.e., no 4-2-4 encoding/decoding, but discrete left total/left and right total/right) produces a stereo 2.0 track.
The fully degenerate case of stereo variable-area (i.e., no 4-2-4 encoding/decoding, and left total/left equal to right total/right) produces a conventional "dual-bilateral" mono 1.0 track.
RCA Photophone system abandoned – Westrex (stereo) variable-area system renamed Photophone
Once the ability to record stereo tracks became a commercial imperative for sound-transfer facilities, the RCA system was abandoned, as it was incapable of producing time-aligned stereo sound negatives. Whereas the Western Electric/Westrex recorders with the ca. 1938 4-ribbon light valve (RA-1231, e.g., but not RA-1231A) were inherently capable of producing time-aligned sound negatives.
The Westrex system was renamed Photophone after the Western Electric and Westrex registered trademarks were sold by AT&T and Litton Industries, respectively, to others, for uses other than cinema sound systems.
Renaming the Westrex system to Photophone was facilitated by the demise of RCA's cinema sound business unit, by the hand of General Electric, RCA's acquirer, and by its failure to protect the Photophone trademark.
The Westrex system, briefly renamed Photophone, is still in use, with more than 100 systems currently in active service, world-wide. Some users, including Disney and Warner Bros., have multiple systems. The RCA system is essentially defunct.
The Westrex system also has the capability of producing a DTS time-code track along with its native stereo variable-area tracks, or DTS time-code alone for use with 70mm and "special venue" prints.
Photophone brand abandoned
The re-use of the Photophone brand was relatively short-lived. After the closure of the immediate successor to Litton, the RA-1231 recorder and its supporting electronics were taken over by yet another successor.
Dolby Digital, originally synonymous with Dolby AC-3, is the name for a family of audio compression technologies developed by Dolby Laboratories. Called Dolby Stereo Digital until 1995, it is lossy compression. The first use of Dolby Digital was to provide digital sound in cinemas from 35 mm film prints. It has since also been used for TV broadcast, radio broadcast via satellite, digital video streaming, DVDs, Blu-ray discs and game consoles.
Dolby Pro Logic is a surround sound processing technology developed by Dolby Laboratories, designed to decode soundtracks encoded with Dolby Surround. The terms Dolby Stereo and LtRt are also used to describe soundtracks that are encoded using this technique.
Fantasound was a sound reproduction system developed by engineers of Walt Disney studios and RCA for Walt Disney's animated film Fantasia, the first commercial film released in stereo.
Dolby Laboratories, Inc. is a company specializing in audio noise reduction, audio encoding/compression, spatial audio, and HDR imaging. Dolby licenses its technologies to consumer electronics manufacturers.
Vitaphone is a sound film system used for feature films and nearly 1,000 short subjects made by Warner Bros. and its sister studio First National from 1926 to 1931. Vitaphone is the last major analog sound-on-disc system and the only one that was widely used and commercially successful. The soundtrack is not printed on the film, but issued separately on phonograph records. The discs, recorded at 33+1⁄3 rpm and typically 16 inches (41 cm) in diameter, are played on a turntable physically coupled to the projector motor while the film is projected. Its frequency response is 4300 Hz. Many early talkies, such as The Jazz Singer (1927), used the Vitaphone system. The name "Vitaphone" derived from the Latin and Greek words, respectively, for "living" and "sound".
Ray Milton Dolby Hon OBE, HonFREng was an American engineer and inventor of the noise reduction system known as Dolby NR. He helped develop the video tape recorder while at Ampex and was the founder of Dolby Laboratories.
A movie projector is an opto-mechanical device for displaying motion picture film by projecting it onto a screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras. Modern movie projectors are specially built video projectors.
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.
Sensurround is the brand name for a process developed by Cerwin-Vega in conjunction with Universal Studios to enhance the audio experience during film screenings, specifically for the 1974 film Earthquake. The process was intended for subsequent use and was adopted for four more films, Midway (1976), Rollercoaster (1977), the theatrical version of Saga of a Star World (1978), the Battlestar Galactica pilot, as well as the compilation film Mission Galactica: The Cylon Attack (1979). Sensurround worked by adding extended-range bass for sound effects. The low-frequency sounds were more felt than heard, providing a vivid complement to onscreen depictions of earth tremors, bomber formations, and amusement park rides. The overall trend toward "multiplex" cinema structures presented challenges that made Sensurround impractical as a permanent feature of cinema.
Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration of two loudspeakers in such a way as to create the impression of sound heard from various directions, as in natural hearing.
Dolby Stereo is a sound format made by Dolby Laboratories. It is a unified brand for two completely different basic systems: the Dolby SVA 1976 system used with optical sound tracks on 35mm film, and Dolby Stereo 70mm noise reduction on 6-channel magnetic soundtracks on 70mm prints.
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 modern sound films use variable-area tracks instead, modern motion picture theaters 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 principally an early version of Movietone.
Sound recording and reproduction is the electrical, mechanical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, singing, instrumental music, or sound effects. The two main classes of sound recording technology are analog recording and digital recording.
Instant Replay is the seventh studio album by the Monkees. Issued 11 months after the cancellation of the group's NBC television series, it is also the first album released after Peter Tork left the group and the only album of the original nine studio albums that does not include any songs featured in the TV show.
The history of sound recording - which has progressed in waves, driven by the invention and commercial introduction of new technologies — can be roughly divided into four main periods:
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.
Auricon cameras were 16 mm film Single System sound-on-film motion picture cameras manufactured in the 1940s through the early 1980s. Auricon cameras are notable because they record sound directly onto an optical or magnetic track on the same film as the image is photographed on, thus eliminating the need for a separate audio recorder. The camera preceded ENG video cameras as the main AV tool of television news gathering due to its portability–and relatively quick production turn-around–where processed negative film image could be broadcast by electronically creating a positive image. Additionally, the Auricon found studio use as a 'kinescope' camera of live video off of a TV screen, but only on early pre-NTSC line-locked monochrome systems.
Center channel refers to an audio channel common to many surround sound formats. It is the channel that is mostly, or fully, dedicated to the reproduction of the dialogue of an audiovisual program. The speaker(s) connected to the center channel are placed in the center of and behind the perforated projection screen, to give the effect that sounds from the center channel are coming from the screen. In many home surround sound units, the center channel is positioned above or below the video screen.
The pallophotophone was a photographic sound recording and playback system developed by General Electric researcher Charles A. Hoxie circa 1922. The RCA Photophone sound-on-film system for motion pictures was later derived from it.
Vitasound was an experimental sound system developed by Warner Brothers in 1939. It was intended to provide a wider sound source and greater dynamic range for music and effects than standard soundtracks of the period. But unlike the near-contemporary Fantasound system used for the roadshow release of Walt Disney's 'Fantasia' it was not a stereophonic system.
References
Citations
↑ History of Sound Motion Pictures, E.W. Kellog, Journal of the SMPTE Vol 64 June 1955
↑ Indeed, the RCA-licensed Maurer recorder could produce either variable-area or variable-density by simply shifting a portion of the optical system at the recordist's discretion.
↑ The Production of Wide-Range, Low-Distortion Optical Soundtracks Utilizing the Dolby Noise Reduction System. Ioan Allen. JSMPTE Vol.84 Sept 1975
↑ Stereophonic Photographic Soundtracks. Ronald E. Uhlig. JSMPTE Vol.82 April 1973
↑ J. Frayne and H. Wolfe, Sound Recording (New York: Wiley & Sons, 1949). Discusses, in the abstract, the components of that which later became today's Photophone (né Western Electric/Westrex) stereo variable-area system, but the component descriptions are spread throughout this essential and definitive text
↑ Two, three or four time-aligned tracks were theoretically possible, and one implementation did, indeed, offer four time-aligned discrete tracks. The four-track experiment was not repeated. All subsequent implementations were two discrete, time-aligned tracks.
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