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106-400: Four channel quadraphonic surround sound can be used to recreate the highly realistic effect of a three-dimensional live concert hall experience in the home. It can also be used to enhance the listener experience beyond the directional limitations of ordinary two channel stereo sound. Quadraphonic audio was the earliest consumer product in surround sound. Since it was introduced to the public in

212-429: 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

318-401: 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

424-462: A diamond shape (centre-front, centre-left, centre-rear, centre-right). Initially (first available in 1969 with th Dynaco SCA-80Q amplifier ), it was introduced as a derived (2:2:4) four channel "decoding" system based on the Hafler circuit , where the back channels played ambient sounds recovered from standard stereo sounds. As such it wasn't used initially used as an encoding method (a similar approach

530-465: 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

636-439: 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

742-447: 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

848-590: 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 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

954-610: A revival since 2000 and new four channel recordings have also been released to the public since this time. A quadraphonic system will reproduce right front, right rear, left front, and left rear audio signals in four separate speakers. The reproduction capability of the rear speakers should be of the same quality or almost the same quality as the front speakers; ideally, a quadraphonic system uses four identical speakers. The first machines used for 4-channel sound recording were analog reel-to-reel tape recorders. These were developed for use by audio engineers in professional studios during

1060-553: 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

1166-513: 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

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1272-528: A specialized demodulator to decode four fully independent sound channels. This allowed for full channel separation. Such systems could be prone to reduced record life. However, more durable vinyl formulations were quickly developed to work around this problem and nearly all discrete LPs use special vinyl. When discrete quadraphonic LPs are played on conventional stereo record players the entire music program can be heard in stereo. The third major format for four-channel vinyl LPs, known as CD-4 or Quadradisc ,

1378-419: A system. Dynaco sold this matrix circuit ( Dynaco QD-1 Quadaptor , introduced in 1971 )with a large and triple high-wattage potentiometer inside. Electronic amateurs could build the circuit much more cheaply – e.g., with a four-position switch (four steps in level of the rear sound from min. to max. level) using fixed resistors of, for example, 20, 10, 5 and 0 (short-circuit) ohms. Because, in practice, only

1484-443: 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

1590-417: A two-channel transmission medium (usually an LP record) before being decoded to four channels and presented to four speakers. To transmit four individual audio signals in a stereo-compatible manner, there must be four simultaneous linear equations to reproduce the original four audio signals at the output. These systems used matrix decoding technology to recover four channels from the two channels recorded on

1696-562: 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

1802-563: 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

1908-510: A ⋂ horseshoe topology. However, all these came too late in the game and were too expensive or difficult to procure for public purchase, to rescue matrix quad from obscurity. By the early 2000s more sophisticated "discrete" multichannel systems had mostly replaced matrix technologies, providing a higher level of performance and full channel independence. Today, software can be used to take the place of hardware decoding. Modern software algorithms are capable of more accurate decoding performance than

2014-469: 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,

2120-399: Is different than for stereo versions of the same recording. Most studio equipment is designed for stereo only, so specialized multichannel mixing consoles and playback systems must be available. For classical music, producers have typically preferred an effect where the orchestra appears in stereo in only the front channels, and the natural reverberation or "echo" of the concert hall is in all

2226-449: Is half of the full speed. The slower speed results in significantly poorer sound quality. RCA Records followed, in April 1970, with its announcement of a four-channel version of the 8-track tape , named Quad-8 or Quadraphonic 8-track tape (later shortened to just Q8 ). These eventually appeared in staggered releases (70 Tapes) split by October, November, and December 1970. The format

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2332-711: Is to say, the four channels produced at the final stage were not truly identical to those with which the process had begun. In order for the effect to work as intended a recording engineer needed to be specially trained for working in each of these formats. Special mixing rules for matrix recording minimize the technological limitations inherent in matrix formats and mask or eliminate undesired side effects. The first of these were basic systems with relatively poor performance developed by Electro-Voice ( EV-4/Stereo-4 ) and Dynaco ( Dynaquad (DY) ). A so-called matrix format, it utilized four sound channels which were "encoded" into two stereo album tracks. These were then "decoded" into

2438-613: 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

2544-508: The SQ system was greatly improved by the introduction of SQ Full Logic decoding in 1975 using the Motorola chips MC1312, MC1314 & MC1315. Both SQ and QS had significant support from major record companies and hardware manufacturers during the 1970s. They also achieved notable sales and market penetration. Unfortunately, due to the similarities in name and technology these could easily be confused by

2650-608: 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

2756-610: The 1950s in Germany by Telefunken and also by Ampex in the United States. Such machines appeared in some European electronic-music studios by 1954. Early attempts to reproduce four channel sound for home playback began with audio laboratory engineers in the late 1960s. Producer Thomas Mowrey, initially working at the Eastman School of Music , was one of the pioneers of classical quadraphonic recording. He later made quadraphonic productions for Deutsche Grammophon and other labels in

2862-471: The 1970s in entertainment media such as broadcast radio, recorded music, television, video cameras , cinema, computer audio, and internet. The word stereophonic derives from 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:

2968-514: The 1970s this station broadcast a signal which could be tuned as two separate stations with conventional stereo receivers. San Francisco classical music station KKHI-FM broadcast the San Francisco Opera in "compatible" (that is, matrix-encoded) quadraphonic format during the 1970s, as did Chicago station WFMT 's live "Chicago Lyric Opera" broadcasts. KRMH -FM ("Good Karma Radio")(San Marcos/Austin, Texas) broadcast in "Quad Stereo" in

3074-439: The 1970s used "matrix" technologies to encode and decode four channels of audio information in a 2-channel medium, usually an LP. The poor decoding performance of early matrix formats was the main reason they disappeared once improved matrix systems arrived. The later matrix systems were based on work by Peter Scheiber . His basic formula used 90° phase-shift circuitry to enable enhanced 4–2–4 matrix systems to be developed, of which

3180-404: The 1970s, particularly among car audio enthusiasts. In the 1970s specialized hardware systems were marketed by major electronic manufacturers to the public for decoding 4-channel recordings. These decoders were often sold as separate electronic components. Decoders were also available as built in features of some audio receivers or amplifiers sold during the 1970s. Many quadraphonic recordings in

3286-404: The 1990s were first intended for movie sound, but also brought multi-channel music reproduction into popularity again. By this time new digitally based formats had been created. Many four channel recordings from the 1970s have been reissued in modern surround sound systems such as Super Audio CD , DTS , Dolby Digital , DVD-Audio and Blu-ray . Multichannel home audio reproduction has experienced

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3392-513: 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 ,

3498-410: 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

3604-551: 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

3710-633: 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

3816-458: 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

3922-461: The audible range and uses the difference channels to separate rear audio information from the main channels. Because the CD-4 system maintains four independent signals throughout the process it can accurately reconstruct the intended four channel sound field. UD-4/UMX was developed by Nippon/Columbia ( Denon ). This is a hybrid discrete/matrix system. Only 35 to 40 items are encoded in this format and it

4028-591: The channels at a time. The last release in the quadraphonic 8-track format was in 1978, although most had stopped appearing by the end of 1976. There were some experiments done with radio broadcasts (e.g., a Cliff Richard concert by the BBC , whose earliest quadraphonic broadcast was in July 1974), but they were short-lived. One of the longest-lived radio broadcasts was WQSR -FM "Quad 102½" in Sarasota, Florida . Throughout most of

4134-457: 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,

4240-495: 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

4346-520: The earlier hardware technologies. All of the multichannel audio systems in common use today are digital systems. Digital multichannel audio has been available for the home since the introduction of surround sound movies in the 1990s using Dolby Digital and DTS. The most common digital media capable of reproducing surround sound music today are Super Audio CD, DVD, and Blu-ray, all of which are capable of playing high-resolution audio with multiple channels. The audio mixing process for four channel sound

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4452-489: The early 1970s from its studios and transmitter near Buda, Texas . WWWW-FM (W4-QUAD 106.7) (Detroit) broadcast QS encoded quadraphonic sound in 1974. KEXL -FM ("KEXL 104.5") (San Antonio, Texas) broadcast in "Quadraphonic" in the early to mid 1970s from its studios in a high-rise office building off Main Plaza. Stereo Stereophonic sound , or more commonly stereo , is a method of sound reproduction that recreates

4558-471: The early 1970s many thousands of quadraphonic recordings have been made. Quadraphonic sound was a commercial failure when first introduced due to a variety of technical issues and format incompatibilities. Four channel audio formats can be more expensive to produce than standard two-channel stereo. Playback requires additional speakers and amplifier channels. It may also require specially designed decoding equipment. The introduction of home cinema products in

4664-506: The early 1970s, but many of these were released only as stereo recordings. A small number of quadraphonic recordings were introduced to the American consumer market by Vanguard Records in June 1969 on reel-to-reel tape. The most popular medium used to market recordings to the public during the 1970s was the vinyl LP phonograph record . Quadraphonic recordings on 8-track tape were also popular in

4770-419: 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 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

4876-687: The first two-channel audio system in Paris in 1881, with 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

4982-467: The format. The competing Stereo-4 system was very similar and can be considered as compatible, as both use very similar decoding matrixes (based on the Hafler circuit ). The left and right rear speakers are connected to the two-channel stereo amplifier via a passive matrix circuit, while the front ones stay directly connected to the amplifier. A lot of stereo material, recorded with a central, non-directional microphone (kidney pattern) placed in front of

5088-557: The highest level was of any use, a more basic set-up with only the fixed 10 ohm resistor at close-to-zero cost is possible. The system requires relatively flat impedance curves for the rear speakers to work properly, which was often the case in the tube-amplifier days. Tube amplifiers had a constant impedance over a wide range, and worked best with high-efficiency speakers. Later on, when transistor amplifiers were used, speakers tended to lose that design feature. (Lower impedance meant higher power output for these amplifiers, compensating for

5194-498: 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

5300-401: 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

5406-412: 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

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5512-479: 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

5618-400: 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

5724-436: The listener. Quadraphonic audio reproduction on vinyl phonograph records was problematic. As technologies advanced rapidly during the 1970s several different solutions were proposed to reproduce four channel sound from LPs. Some of these systems were much more successful than others. The simplest systems were "derived" (2–2–4) formats. These were soon followed by much more sophisticated "matrix" (4–2–4) formats, and finally, by

5830-459: The lower efficiency of such designs.) The system worked best using a transistor-based stereo amplifier, low-efficiency front speakers, and high-efficiency, constant impedance rear speakers. The encoding was unusual in that, like the Stereo-4 system, it did not use 90° phase shifters. During 2016, recording engineer Stephen Desper in several online forum posts publicly refuted the common rumour that

5936-410: The main channels. The difference signals are encoded in ultrasonic carrier frequencies in the range of 30 kHz, which is above the audible range. CD-4 requires a specialized phono cartridge with a "Shibata" stylus to read these additional high frequencies. The combined signals are then sent to a special demodulator for four channel decoding. The demodulator converts the ultrasonic signals back into

6042-444: The most advanced "discrete" (4–4–4) formats. Derived (2–2–4) formats are simple and inexpensive electronic solutions that add or extract rear "ambience" or "reverberation" sound channels from stereo records i.e., studio reverb, audience applause, etc. There is no precise placement of individual instruments in the rear channels. With matrix formats four channels are converted (encoded) down to two channels. These are then passed through

6148-561: 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 ,

6254-480: 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

6360-597: 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

6466-413: The orchestra, possessed suitable phase difference stereo signals. When taken from this passive speaker matrix for the rear channels, they produced a quasi-quadraphonic effect at low cost (the patent specifies the use of one fixed 10 ohm resistor and three variable 20 ohm resistors in a star arrangement). Especially for classical music, a fine impression of concert-hall ambiance is achieved with such

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6572-401: The original four sound channels. But with poor decode performance, these systems failed to match the accuracy or channel independence of later matrix formats. The original systems (DY and EV-4) suffered from low front left-right separation (around 12 dB) and a poor rear left-right separation of 2 dB. The decoders were designed more to give an effect rather than accurate decoding, which

6678-464: The original four sound channels. The QS system debuted in the United States in March 1971 and was improved by their Vario-Matrix system in 1973. The second, SQ , was developed and marketed by Columbia Records and Sony and entered the US market in April 1971. The SQ format was also used by companies such as EMI in Great Britain, who pressed several SQ album releases. The sound separation of

6784-425: 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

6890-468: The positions of the recorded objects. Since each microphone records each wavefront at a slightly different time, 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

6996-540: 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

7102-415: The public. Discrete reproduction describes a quadraphonic system in which all four channels are fully independent of each other. As its name suggests, with discrete formats the original four audio channels are passed through a four-channel transmission medium and presented to a four-channel reproduction system and fed to four speakers. This is defined as a 4–4–4 system. Discrete phonograph systems use

7208-516: The rear channels that are of equal importance to the front channels. It can expand on the listener's sense of direction and spaciousness in a way similar to what happened when recording engineers introduced stereo recording. In some four channel recordings sounds move in full rotation around the listener. Mixing engineers can also aim for a hybrid effect between styles. While quadraphonic effects have sometimes been considered artificial, musical enjoyment can be dramatically enhanced by more fully involving

7314-411: The record. Matrix systems can have a significant level of channel independence but not full channel separation. Matrix quadraphonic recordings can be played in two channels on conventional stereo record players. There are varying levels of stereo and mono compatibility in these systems. The term compatible indicates that: This 4:2:4 process could not be accomplished without some information loss. That

7420-421: 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

7526-423: 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

7632-458: The relative positions of objects and events recorded. During two-channel stereo recording, two microphones are placed in strategically chosen locations relative to 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

7738-583: 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,

7844-688: 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

7950-635: 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

8056-479: 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 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

8162-430: 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

8268-454: 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

8374-469: 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:

8480-512: The speakers. Some live concert recordings of popular music have also been mixed this way. Classical recordings rarely place primary or solo instruments in the rear channels, though it is done occasionally. A few classical recordings have been made from a perspective in which the listener seems to be seated in the middle of the orchestra. One example is the 1973 Columbia Masterworks recording of Béla Bartók 's Concerto for Orchestra , conducted by Pierre Boulez . The original four channel recording

8586-407: The tape running in the same direction. Pre-recorded four channel reel-to-reel tapes were recorded at 7 1 ⁄ 2 inches per second (IPS), which is the fastest speed used for consumer grade reel-to-reel machines. By comparison stereo pre-recorded reel-to-reel tapes have 2 different programs with each running the opposite direction. Many stereo tapes were recorded at only 3 3 ⁄ 4 IPS, which

8692-425: 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

8798-413: The two main leaders were Columbia 's SQ and Sansui 's QS systems. The three most popular quadraphonic LP formats in the 1970s were SQ (Stereo Quadraphonic) , QS (Regular Matrix) and CD-4 (Compatible Discrete 4) / Quadradisc . The Japanese governing body and audio hardware manufacturers defined standards for quadraphonic sound. RM ( Regular Matrix ) was used a synonym for QS, QM ( Quadraphonic Matrix

8904-496: 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

9010-464: 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

9116-523: 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

9222-616: 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

9328-420: 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.,

9434-485: Was almost identical in appearance to stereo 8-tracks, except for a small sensing notch in the upper left corner of the cartridge. This signaled a quadraphonic 8-track player to combine the odd tracks as audio channels for program 1, and the even tracks as channels for program 2. The format was not backward-compatible with stereo or mono players; although quadraphonic players would play stereo 8-tracks, playing quadraphonic tapes on stereo players resulted in hearing only one-half

9540-456: 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

9646-417: 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

9752-653: 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

9858-601: 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 . Dynaquad Dynaquad , or DY , was a matrix decoder 4-channel quadraphonic sound system developed by Dynaco in 1969. The system originally had four speakers that were arranged in

9964-637: Was devised by the Japanese JVC Corporation along with its US counterpart RCA Records . This quadraphonic format was first marketed in the United States in May 1972. A fully discrete system, it eschewed matrix technologies in favor of a method similar to the encoding of stereo FM broadcasts. With stereo records, the system uses 2 main left and right audio channels, and this is what allows CD-4 to maintain compatibility with conventional stereo playback. CD-4 also adds 2 additional "difference" audio channels to

10070-456: Was intended by the producer or recording engineer. Improved systems based on Peter Scheiber 's work on utilizing 90-degree phase-shift circuitry came later, namely the QS and SQ systems. The first of these, known as QS , was developed by Sansui Electric . A so-called matrix format, it utilized four sound channels, which were "encoded" into two stereo album tracks. These were then "decoded" into

10176-454: Was mainly due to limitations in both systems. Since both systems were very closely related mathematically, users only needed one decoder of either system to playback albums of both systems. The differences between the early and late matrix systems were so vast, it made decoding DY/EV-4 with either SQ or QS decoders with accuracy impossible; the results often being a "smeared" or poorly defined sound stage, which could be vastly different from what

10282-807: Was marketed only in the UK, Europe, and Japan. The short-lived system suffered from incompatibility with regular stereo playback due to phase differences between the left and right channels. UD-4 was less critical in its setup than CD-4 because the carriers did not have to handle frequencies as high as those found in the CD-4 system. Quadraphonic systems based on tape were also introduced, based on new equipment capable of playing four discrete channels. These recordings are all discrete 4–4–4 recordings released in reel-to-reel and 8-track cartridge formats. Specially designed four channel machines were required to play these recordings. They are not compatible with stereo players. In these systems all four available tracks were recorded on

10388-527: 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

10494-549: 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

10600-493: 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

10706-485: Was released on matrix LP and 8-track tape, and reissued on the Super Audio CD format by Dutton Vocalion in 2018. Notes supplied with the recording indicate the direction from which each group of instruments can be heard. Pop, rock and jazz music producers have tended to employ a mixing style with a relatively high degree of musical separation between the four channels. This type of recording may place musical sounds in

10812-431: 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

10918-682: Was used for Stereo-4 and Dynaquad ) and QX ( QuadXtra , based on D.H. Cooper "Dual-Triphonic") for UD4 . With Scheiber and Martin Willcocks, Jim Fosgate developed the Tate II 101 SQ decoder, which produced a very accurate sound field by using gain riding and the Haas effect to mask decoding artifacts. It used custom, hand-assembled and ‑calibrated circuitry with components sorted to 1%, for exact performance. Sansui's QSD-series decoders and QRX-series receivers were very good, even synthesizing left-right stereo into

11024-597: 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

11130-428: 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

11236-566: Was used on the Electrovoice Stereo-4 system). A simpler form of Dynaquad was adopted, allowing an easy adaptation of existing home setups. The two forward speakers remain in their normal positions, with the user only needing to add two similarly positioned back speakers, forming a square (front-left, front-right, back-left, back-right). Four channel record pioneers Vanguard Records started to use it as an encoding/decoding matrix (4:2:4 format) in 1971. There were few albums released in

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