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74-691: (Redirected from Multi-channel ) Multichannel or multi-channel may refer to: Multichannel audio, i.e. Stereophonic sound , namely two channel audio Surround sound , more than two channel audio Ambisonics , a studio or live way of recording with many channels Offering multiple audio tracks on a broadcast channel: see Sound multiplex in broadcasting Multichannel television sound , an American standard for analogue television Having or offering multiple television channels: see Multichannel television Digital multicast television network Multichannel Multipoint Distribution Service (MMDS),

148-429: A binaural record out of it. This consisted of two separate channels cut into two separate groups of grooves running next to each other, one running from the edge of the disc to halfway through and the other starting at the halfway point and ending up towards the label. He used two lateral grooves with a 500 Hz crossover in the inner track to try and compensate for the lower fidelity and high-frequency distortion on

222-401: A decade, and broadcasters were looking for better materials from which to make phonograph records as well as a better format in which to record them to play over the narrow and thus inherently noisy radio channel. As radio had been playing the same shellac discs available to the public, it was found that, even though the playback system was now electric rather than acoustic, the surface noise on

296-465: A hill-and-dale (vertically modulated) format on his cylinders and discs since 1877, and Berliner had been recording in a side-to-side (lateral) format since shortly thereafter. Each format developed on its own trajectory until the late 1920s when electric recording on disc, utilizing a microphone, surpassed acoustic recording which required a loud performance into what amounted to a megaphone in reverse. At that time, AM radio had been around for roughly

370-439: A monophonic system since a stereo system contains two preamplifiers, two amplifiers, and two speaker systems. In addition, the user would need an FM stereo tuner, to upgrade any tape recorder to a stereo model, and to have their phonograph fitted with a stereo cartridge. In the early days, it was not clear whether consumers would think the sound was so much better as to be worth twice the price. Thomas Edison had been recording in

444-447: A more modern 24 fps system with brand-new 65 mm self-blimped production cameras ( Mitchell BFC ... "Blimped Fox Camera") and brand-new 65 mm MOS cameras (Mitchell FC ... "Fox Camera") and brand-new Super Baltar lenses in a wide variety of focal lengths, first employed on South Pacific . Essentially, although Todd-AO was also available to others, the format became Fox's premier origination and presentation apparatus, replacing

518-567: A separate listening room. Several stereophonic test recordings, using two microphones connected to two styli cutting two separate grooves on the same wax disc, were made with Leopold Stokowski and the Philadelphia Orchestra at Philadelphia's Academy of Music in March 1932. The first (made on March 12, 1932), of Scriabin's Prometheus: Poem of Fire , is the earliest known surviving intentional stereo recording. The performance

592-602: A series of telephone transmitters connected from the stage of the Paris Opera to a suite of rooms at the Paris Electrical Exhibition, where listeners could hear a live transmission of performances through receivers for each ear. Scientific American reported: Every one who has been fortunate enough to hear the telephones at the Palais de l'Industrie has remarked that, in listening with both ears at

666-520: A somewhat artificial six-track panning method. A process known somewhat derogatorily as the Columbia Spread was often used to synthesize Left Center and Right Center from a combination of Left and Center and Right and Center, respectively, or, for effects, the effect could be "panned" anywhere across the five stage speakers using a one-in/five-out pan pot. Dolby, who did not approve of this practice, which results in loss of separation, instead used

740-799: A standard for analogue television Multichannel television in Canada Multichannel television in the United States Multichannel marketing Multi-channel network , a YouTube classification of for-profit channels Multichannel News MPEG Multichannel MADI , Multichannel Audio Digital Interface McASP , Multichannel Audio Serial Port Scanning Multichannel Microwave Radiometer Joint multichannel trunking and switching system Multibus , Multichannel I/O Bus MVDDS , Multichannel Video and Data Distribution Service MMDF , Multichannel Memorandum Distribution Facility Topics referred to by

814-587: A system capable of recording colour video. The first recording systems designed to be mobile (and thus usable outside the studio) were the Portapak systems starting with the Sony DV-2400 in 1967. This was followed in 1981 by the Betacam system where the tape recorder was built into the camera making a camcorder. While some video cameras have built in lenses others use interchangeable lenses connected via

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888-443: A time before intentional stereophonic recording technology existed. Modern stereophonic technology was invented in the 1930s by British engineer Alan Blumlein at EMI , who patented stereo records, stereo films, and also surround sound. In early 1931, Blumlein and his wife were at a local cinema. The sound reproduction systems of the early talkies invariably only had a single set of speakers – which could lead to

962-572: A vast array of sounds, ranging from railroad sounds to thunderstorms. By 1953, Cook had a catalog of about 25 stereo records for sale to audiophiles . The first stereo recordings using magnetic tape were made in Germany in the early 1940s using Magnetophon recorders. Around 300 recordings were made of various symphonies, most of which were seized by the Red Army at the end of World War II. The recordings were of relatively high fidelity , thanks to

1036-563: A vertical fashion to minimize rumble. The overhead in this scheme limited the playing time to slightly longer than a single even at 33 + 1 ⁄ 3 RPM on a 12-inch disc. Another failed experiment in the late 1920s and early '30s involved recording the left channel on one side of the disc and recording the right channel on the other side of the disc. These were manufactured on twin film-company recording lathes which ran in perfect sync with one another, and were capable of counter-clockwise as well as conventional clockwise recording. Each master

1110-570: A way as to create the impression of sound heard from various directions, as in natural hearing. Because the multi-dimensional perspective is the crucial aspect, the term stereophonic also applies to systems with more than two channels or speakers such as quadraphonic and surround sound . Binaural sound systems are also stereophonic . Stereo sound has been in common use since the 1970s in entertainment media such as broadcast radio, recorded music, television, video cameras , cinema, computer audio, and internet. The word stereophonic derives from

1184-435: Is live television , where the camera feeds real time images directly to a screen for immediate observation. A few cameras still serve live television production, but most live connections are for security , military/tactical, and industrial operations where surreptitious or remote viewing is required. In the second mode the images are recorded to a storage device for archiving or further processing; for many years, videotape

1258-476: Is Cinerama was still playing only in New York City, most moviegoing audiences heard stereophonic sound for the first time with House of Wax , an early 3-D film starring Vincent Price and produced by Warner Bros. Unlike the 4-track mag release-print stereo films of the period which featured four thin strips of magnetic material running down the length of the film, inside and outside the sprocket holes,

1332-427: Is different from Wikidata All article disambiguation pages All disambiguation pages Stereophonic sound 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 (or stereo headphones ) in such

1406-442: Is the discrete cosine transform (DCT), a lossy compression technique that was first proposed in 1972. Practical digital video cameras were enabled by DCT-based video compression standards, including the H.26x and MPEG video coding standards introduced from 1988 onwards. The transition to digital television gave a boost to digital video cameras. By the early 21st century, most video cameras were digital cameras . With

1480-424: Is then reproduced over multiple loudspeakers to recreate, as closely as possible, the live sound. Secondly artificial or pan stereo, in which a single-channel ( mono ) sound is reproduced over multiple loudspeakers. By varying the relative amplitude of the signal sent to each speaker, an artificial direction (relative to the listener) can be suggested. The control which is used to vary this relative amplitude of

1554-633: The Chicago World's Fair in 1933 using a dummy with microphones instead of ears . The two signals were sent out over separate AM station bands. Utilizing selections recorded by the Philadelphia Orchestra , under the direction of Leopold Stokowski , intended for but not used in Walt Disney's Fantasia , the Carnegie Hall demonstration by Bell Laboratories on April 9 and 10, 1940, used three huge speaker systems. Synchronization

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1628-453: The Greek στερεός ( stereós , "firm, solid") + φωνή ( phōnḗ , "sound, tone, voice") and it was coined in 1927 by Western Electric , by analogy with the word stereoscopic . Stereo sound systems can be divided into two forms: the first is true or natural stereo in which a live sound is captured, with any natural reverberation present, by an array of microphones . The signal

1702-625: The Théâtrophone , and in England from 1895 to 1925 as the Electrophone . Both were services available by coin-operated receivers at hotels and cafés, or by subscription to private homes. There have been cases in which two recording lathes (for the sake of producing two simultaneous masters) were fed from two separate microphones; when both masters survive, modern engineers have been able to synchronize them to produce stereo recordings from

1776-520: The 3-D production of The Charge at Feather River , and Island in the Sky . Unfortunately, as of 2012, the stereo magnetic tracks to both these films are considered lost forever. In addition, a large percentage of 3-D films carried variations on three-track magnetic sound: It Came from Outer Space ; I, the Jury ; The Stranger Wore a Gun ; Inferno ; Kiss Me, Kate ; and many others. Inspired by Cinerama ,

1850-410: The 70 mm prints would be mixed for stereo, while the 35 mm reduction prints would be remixed for mono. Some films shot in 35 mm, such as Camelot , featured four-track stereophonic sound and were then blown up to 70 mm so that they could be shown on a giant screen with six-track stereophonic sound. Unfortunately however, many of these presentations were only pseudo stereo, utilizing

1924-562: The CinemaScope 55 mm system. Current DVDs of the two CinemaScope feature titles were transferred from the original 55 mm negatives, often including the separate 35 mm films as extras for comparison. Beginning in 1957, films recorded in stereo (except for those shown in Cinerama or Todd-AO) carried an alternate mono track for theatres not ready or willing to re-equip for stereo. From then until about 1975, when Dolby Stereo

1998-660: The King of Siam , The Day the Earth Stood Still and Sun Valley Serenade which, along with Orchestra Wives , feature the only stereophonic recordings of the Glenn Miller Orchestra as it was during its heyday of the Swing Era . Walt Disney began experimenting with multichannel sound in the early 1930s as noted above. The first commercial motion picture to be exhibited with stereophonic sound

2072-412: The advent of digital video capture, the distinction between professional video cameras and movie cameras has disappeared as the intermittent mechanism has become the same. Nowadays, mid-range cameras exclusively used for television and other work (except movies) are termed professional video cameras. Early video could not be directly recorded. The first somewhat successful attempt to directly record video

2146-458: The artistic adjustment of overall volume and the relative volume of each track in relation to the others. Stokowski, who was always interested in sound reproduction technology personally participated in the enhancement of the sound at the demonstration. The speakers produced sound levels of up to 100 decibels, and the demonstration held the audience "spellbound, and at times not a little terrified", according to one report. Sergei Rachmaninoff , who

2220-457: The disc would mask the music after just a few plays. The development of acetate, bakelite, and vinyl, and the production of radio broadcast transcriptions helped to solve this. Once these considerably quieter compounds were developed, it was discovered that the rubber-idler-wheel-driven turntables of the period had a great deal of low-frequency rumble – but only in the lateral plane. So, even though with all other factors being equal,

2294-503: The discovery of AC bias . A 1944 recording of Anton Bruckner 's Symphony No. 8 directed by Herbert von Karajan and the Orchester der Berliner Staatsoper and a 1944 or 1945 recording of Walter Gieseking playing Beethoven 's Piano Concerto No. 5 (with anti-aircraft fire audible in the background) are the only recordings still known to exist. In the US, stereo magnetic tape recording

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2368-498: The inner track. Each groove needed its own monophonic needle and cartridge on its own branch of the tonearm, and each needle was connected to a separate amplifier and speaker. This setup was intended to demonstrate Cook's cutter heads at a New York audio fair. It was not intended to promote the binaural process; but soon afterward, the demand for such recordings and the equipment to play them grew, and Cook's company, Cook Records, began to produce such records commercially. Cook recorded

2442-401: The introduction of digital cinema , Dolby Surround 7.1 and Dolby Atmos in 2010 and 2012 respectively. The progress of stereophonic sound was paced by the technical difficulties of recording and reproducing two or more channels in synchronization with one another and by the economic and marketing issues of introducing new audio media and equipment. A stereo system cost up to twice as much as

2516-412: The latter of which used up to four separate magnetic soundtracks. VistaVision took a simplified, low-cost approach to stereophonic sound; its Perspecta system featured only a monaural track, but through subaudible tones, it could change the direction of the sound to come from the left, right or both directions at once. Because of the standard 35 mm-size film, CinemaScope and its stereophonic sound

2590-485: The left center and right center channels for LFE (low-frequency enhancement) utilizing the bass units of the otherwise redundant intermediate front speakers, and later the unused HF capacity of these channels to provide for stereo surround in place of the mono surround. Dolby Stereo was succeeded by Dolby Digital 5.1 in the cinema, which retained the Dolby Stereo 70 mm 5.1 channel layout, and more recently with

2664-400: The left channel was recorded laterally and the right channel was recorded vertically, still utilizing a standard 3-mil 78-RPM groove, over three times larger than the modern LP stylus of the late 20th Century. In this system all the low-frequency rumble was in the left channel and all the high-frequency distortion was in the right channel. Over a quarter of a century later, it was decided to tilt

2738-659: The mechanical Nipkow disk and used in experimental broadcasts through the 1910s–1930s. All-electronic designs based on the video camera tube , such as Vladimir Zworykin 's Iconoscope and Philo Farnsworth 's image dissector , supplanted the Nipkow system by the 1930s. These remained in wide use until the 1980s, when cameras based on solid-state image sensors such as the charge-coupled device (CCD) and later CMOS active-pixel sensor (CMOS sensor) eliminated common problems with tube technologies such as image burn-in and streaking and made digital video workflow practical, since

2812-561: The movie industry moved quickly to create simpler and cheaper widescreen systems, the first of which, Todd-AO , was developed by Broadway promoter Michael Todd with financial backing from Rodgers and Hammerstein, to use a single 70 mm film running at 30 frames per second with 6 magnetic soundtracks, for their screen presentation of Oklahoma! . Major Hollywood studios immediately rushed to create their own unique formats, such as MGM 's Camera 65 , Paramount Pictures ' VistaVision and Twentieth Century-Fox Film Corporation 's CinemaScope ,

2886-480: The movies in 1927, the speed of radio program transcriptions was reduced to match, once again to inhibit playback of the discs on normal home consumer equipment. Even though the stylus size remained the same as consumer records at either 3 mils (76 μm) or 2.7 mils (69 μm), the disc size was increased from 12 inches (30 cm) to the same 16 inches (41 cm) as those used in early talking pictures in order to create further incompatibility. Now, not only could

2960-617: The orchestra's conductor, was present in Constitution Hall to control the sound mix. Five years later, the same system would be expanded onto multichannel film recording and used from the concert hall in Philadelphia to the recording labs at Bell Labs in New Jersey in order to record Walt Disney 's Fantasia (1940) in what Disney called Fantasound . Later that same year, Bell Labs also demonstrated binaural sound, at

3034-425: The other three. The film was not initially a financial success, however, after two months of road-show exhibition in selected cities, its soundtrack was remixed into mono sound for general release. It was not until its 1956 re-release that stereo sound was restored to the film. A Cinerama demonstration film by Lowell Thomas and Mike Todd titled This is Cinerama was released on September 30, 1952. The format

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3108-592: The output of the sensor is digital so it does not need conversion from analog. The basis for solid-state image sensors is metal–oxide–semiconductor (MOS) technology, which originates from the invention of the MOSFET (MOS field-effect transistor) at Bell Labs in 1959. This led to the development of semiconductor image sensors, including the CCD and later the CMOS active-pixel sensor . The first semiconductor image sensor

3182-540: The process, Carousel and The King and I , were released in 35 mm CinemaScope reduction prints. To compensate, the premiere engagement of Carousel used a six-track magnetic full-coat in an interlock, and a 1961 re-release of The King and I , featured the film printed down to 70 mm with a six-channel soundtrack. Eventually, 50 complete sets of combination 55/35 mm projectors and penthouse reproducers were completed and delivered by Century and Ampex, respectively, and 55 mm release print sound equipment

3256-421: The recording head 45 degrees off to the right side so that both the low-frequency rumble and high-frequency distortion were shared equally by both channels, producing the 45/45 system we know today. In 1952, Emory Cook (1913–2002), who already had become famous by designing new feedback disk-cutter heads to improve sound from tape to vinyl, took the two-channel high-fidelity system described above and developed

3330-423: The records not be played on home equipment due to incompatible recording format and speed, they would not even fit on the player, which suited the copyright holders. An experimental format in the 1920s split the signal into two parts, bass and treble, and recording the treble on its own track near the edge of the disc in a lateral format minimizing high-frequency distortion, and recording the bass on its own track in

3404-583: The same left, center, right and surround sound of the original CinemaScope system of 1953 by using a single standard-width optical track. This important development, marketed as Dolby Stereo , finally brought stereo sound to so-called flat (non- anamorphic ) widescreen films, most commonly projected at aspect ratios of 1.75:1 or 1.85:1. Producers often took advantage of the six magnetic soundtracks available for 70 mm film release prints, and productions shot in either 65 mm or to save money, in 35 mm and then blown up to 70 mm. In these instances,

3478-421: The same term [REDACTED] This disambiguation page lists articles associated with the title Multichannel . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Multichannel&oldid=1141369827 " Category : Disambiguation pages Hidden categories: Short description

3552-692: The same year, twenty-five years before that method became the standard for stereo phonograph discs. These discs used the two walls of the groove at right angles in order to carry the two channels. In 1934, Blumlein recorded Mozart 's Jupiter Symphony conducted by Sir Thomas Beecham at Abbey Road Studios in London using his vertical-lateral technique. Much of the development work on this system for cinematic use did not reach completion until 1935. In Blumlein's short test films (most notably, "Trains at Hayes Station", which lasts 5 minutes 11 seconds, and, "The Walking & Talking Film"), his original intent of having

3626-635: The screen, two surround channels in the rear of the theater, plus a sync track to interlock the four machines, which were specially outfitted with aircraft servo-motors made by Ampex . The advent of multitrack magnetic tape and film recording of this nature made high-fidelity synchronized multichannel recording more technically straightforward, though costly. By the early 1950s, all of the major studios were recording on 35 mm magnetic film for mixing purposes, and many of these so-called individual angles still survive, allowing for soundtracks to be remixed into stereo or even surround. In April 1953, while This

3700-486: The signal is known as a pan-pot (panoramic potentiometer). By combining multiple pan-potted mono signals together, a complete, yet entirely artificial, sound field can be created. In technical usage, true stereo means sound recording and sound reproduction that uses stereographic projection to encode the relative positions of objects and events recorded. During two-channel stereo recording, two microphones are placed in strategically chosen locations relative to

3774-430: The somewhat disconcerting effect of the actor being on one side of the screen whilst his voice appeared to come from the other. Blumlein declared to his wife that he had found a way to make the sound follow the actor across the screen. The genesis of these ideas is uncertain, but he explained them to Isaac Shoenberg in the late summer of 1931. His earliest notes on the subject are dated 25 September 1931, and his patent had

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3848-517: The sound follow the actor was fully realized. In the United States, Harvey Fletcher of Bell Laboratories was also investigating techniques for stereophonic recording and reproduction. One of the techniques investigated was the wall of sound , which used an enormous array of microphones hung in a line across the front of an orchestra. Up to 80 microphones were used, and each fed a corresponding loudspeaker, placed in an identical position, in

3922-405: The sound source, with both recording simultaneously. The two recorded channels will be similar, but each will have distinct time-of-arrival and sound-pressure-level information. During playback, the listener's brain uses those subtle differences in timing and sound level to triangulate the positions of the recorded objects. Since each microphone records each wavefront at a slightly different time,

3996-469: The sound system developed for House of Wax , dubbed WarnerPhonic, was a combination of a 35 mm fully coated magnetic film that contained the audio tracks for left, center and right speakers, interlocked with the two dual-strip Polaroid system projectors, one of which carried a mono optical surround track and one that carried a mono backup track use in the event anything should go wrong. Only two other films featured this unique hybrid WarnerPhonic sound:

4070-425: The title "Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproducing Systems". The application was dated 14 December 1931, and was accepted on 14 June 1933 as UK patent number 394,325 . The patent covered many ideas in stereo, some of which are used today and some not. Some 70 claims include: Blumlein began binaural experiments as early as 1933, and the first stereo discs were cut later

4144-500: The two telephones, the sound takes a special character of relief and localization which a single receiver cannot produce... This phenomenon is very curious, it approximates to the theory of binauricular audition, and has never been applied, we believe, before to produce this remarkable illusion to which may almost be given the name of auditive perspective. This two-channel telephonic process was commercialized in France from 1890 to 1932 as

4218-464: The vertical plane of recording on disc had the higher fidelity, it was decided to record vertically to produce higher-fidelity recordings on these new materials, for two reasons, the increase in fidelity by avoiding the lateral rumble and to create incompatibility with home phonographs which, with their lateral-only playback systems, would only produce silence from a vertically modulated disc. After 33 + 1 ⁄ 3 RPM recording had been perfected for

4292-462: The wavefronts are out of phase ; as a result, constructive and destructive interference can occur if both tracks are played back on the same speaker. This phenomenon is known as phase cancellation . Coincident-pair microphone arrangements produce stereo recordings with minimal phase difference between channels. Clément Ader demonstrated the first two-channel audio system in Paris in 1881, with

4366-535: Was Walt Disney's Fantasia , released in November 1940, for which a specialized sound process ( Fantasound ) was developed. As in the Carnegie Hall demonstrations six months earlier, Fantasound used a separate film containing four optical soundtracks. Three of the tracks were used to carry left, center and right audio, while the fourth track carried three tones which individually controlled the volume level of

4440-616: Was a widescreen process featuring three separate 35 mm motion picture films plus a separate sound film running in synchronization with one another at 26 fps, adding one picture panel each to the viewer's left and right at 45-degree angles, in addition to the usual front and center panel, creating a truly immersive panoramic visual experience, comparable in some ways to today's curved screen IMAX OMNI . The Cinerama audio soundtrack technology, developed by Hazard E. Reeves , utilized seven discrete sound tracks on full-coat magnetic 35 mm film. The system featured five main channels behind

4514-420: Was achieved by making the recordings in the form of three motion picture soundtracks recorded on a single piece of film with a fourth track being used to regulate volume expansion. This was necessary due to the limitations of dynamic range on optical motion picture film of the period, however, the volume compression and expansion were not fully automatic, but were designed to allow manual studio enhancement ; i.e.,

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4588-456: Was also reserved for dramas with a strong reliance on sound effects or music, such as The Graduate . The Westrex Stereo Variable-Area system was developed in 1977 for Star Wars , and was no more expensive to manufacture in stereo than it was for mono. The format employs the same Western Electric/Westrex/Nuoptix RA-1231 recorder, and coupled with QS quadraphonic matrixing technology licensed to Dolby Labs from Sansui, this system can produce

4662-417: Was capable of being retrofitted into existing theaters. CinemaScope 55 was created by the same company in order to use a larger form of the system (55 mm instead of 35 mm) to allow for greater image clarity onscreen, and was supposed to have had 6-track stereo instead of four. However, because the film needed a new, specially designed projector, the system proved impractical, and the two films made in

4736-677: Was delivered by Western Electric. Several samples of 55 mm sound prints can be found in the Sponable Collection at the Film and Television Archives at Columbia University . The subsequently abandoned 55/35 mm Century projector eventually became the Century JJ 70/35MM projector. After this disappointing experience with their proprietary CinemaScope 55 mm system, Fox purchased the Todd-AO system and re-engineered it into

4810-537: Was demonstrated on standard 1/4-inch tape for the first time in 1952, using two sets of recording and playback heads, upside-down and offset from one another. A year later, Remington Records began recording a number of its sessions in stereo, including performances by Thor Johnson and the Cincinnati Symphony Orchestra . Video camera Video cameras are used primarily in two modes. The first, characteristic of much early broadcasting,

4884-406: Was in 1927 with John Logie Baird ’s disc based Phonovision . The discs were unplayable with the technology of the time although later advances allowed the video to be recovered in the 1980s. The first experiments with using tape to record a video signal took place in 1951. The first commercially released system was Quadruplex videotape produced by Ampex in 1956. Two years later Ampex introduced

4958-532: Was on hand to try out the new technology, recording onto a special proprietary nine-track sound system at the Academy of Music in Philadelphia, during the making of the movie One Hundred Men and a Girl for Universal Pictures in 1937, after which the tracks were mixed down to one for the final soundtrack. A year later, MGM started using three tracks instead of one to record the musical selections of movie soundtracks, and very quickly upgraded to four. One track

5032-559: Was part of an all-Russian program including Mussorgsky 's Pictures at an Exhibition in the Ravel orchestration, excerpts of which were also recorded in stereo. Bell Laboratories gave a demonstration of three-channel stereophonic sound on April 27, 1933, with a live transmission of the Philadelphia Orchestra from Philadelphia to Constitution Hall in Washington, D.C. over multiple Class A telephone lines. Leopold Stokowski, normally

5106-493: Was present at the demonstration, commented that it was "marvellous" but "somehow unmusical because of the loudness." "Take that Pictures at an Exhibition ", he said. "I didn't know what it was until they got well into the piece. Too much 'enhancing', too much Stokowski." In 1937, Bell Laboratories in New York City gave a demonstration of two-channel stereophonic motion pictures, developed by Bell Labs and Electrical Research Products, Inc. Once again, conductor Leopold Stokowski

5180-431: Was run separately through the plating process, lined up to match, and subsequently mounted in a press. The dual-sided stereo disc was then played vertically, first in a system that featured two tonearms on the same post facing one another. The system had trouble keeping the two tonearms in their respective synchronous revolutions. Five years later, Bell Labs was experimenting with a two-channel lateral-vertical system, where

5254-525: Was the charge-coupled device, invented at Bell Labs in 1969, based on MOS capacitor technology. The NMOS active-pixel sensor was later invented at Olympus in 1985, which led to the development of the CMOS active-pixel sensor at NASA 's Jet Propulsion Laboratory in 1993. Practical digital video cameras were also enabled by advances in video compression , due to the impractically high memory and bandwidth requirements of uncompressed video . The most important compression algorithm in this regard

5328-405: Was the primary format used for this purpose, but was gradually supplanted by optical disc , hard disk , and then flash memory . Recorded video is used in television production, and more often surveillance and monitoring tasks in which unattended recording of a situation is required for later analysis. Modern video cameras have numerous designs and use: The earliest video cameras were based on

5402-597: Was used for dialogue, two for music, and one for sound effects. The very first two-track recording MGM made (although released in mono) was "It Never Rains But What It Pours" by Judy Garland , recorded on June 21, 1938, for the movie Love Finds Andy Hardy . In the early 1940s, composer-conductor Alfred Newman directed the construction of a sound stage equipped for multichannel recording for 20th Century Fox studios. Several soundtracks from this era still exist in their multichannel elements, some of which have been released on DVD, including How Green Was My Valley , Anna and

5476-428: Was used for the first time in films, most motion pictures – even some from which stereophonic soundtrack albums were made, such as Zeffirelli 's Romeo and Juliet  – were still released in monaural sound, stereo being reserved almost exclusively for expensive musicals such as West Side Story , My Fair Lady and Camelot , or epics such as Ben-Hur and Cleopatra . Stereo

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