CX is a

noise reduction Noise reduction is the process of removing noise from a signal. Noise reduction techniques exist for audio and images. Noise reduction algorithms may distort the signal to some degree. Noise rejection is the ability of a circuit to isolate an un ...

system for recorded

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analo ...

audio. It was developed by

CBS Laboratories CBS Laboratories or CBS Labs (later known as the CBS Technology Center or CTC) was the technology research and development organization of the CBS television network. Innovations developed at the labs included many groundbreaking broadcast, indust ...

(a division of CBS) in the late 1970s as a low-cost competitor to other noise reduction (NR) systems such as

dbx disc dbx is a family of noise reduction systems developed by the company of the same name. The most common implementations are dbx Type I and dbx Type II for analog tape recording and, less commonly, vinyl LPs. A separate implementation, known as db ...

and

High-Com II The High Com (also as HIGH COM, both written with a thin space) noise reduction system was developed by Telefunken, Germany, in the 1970s as a high quality high compression analogue compander for audio recordings. High Com ...

, and was officially introduced in 1981. The name ''CX'' was derived from "Compatible eXpansion", a feature of the technique. __TOC__

Use on vinyl LP records

CX was originally designed by CBS as a noise-reduction technology for vinyl LP records, similar to the earlier dbx disc (based on dbx II) and

systems, but, like the later UC system, it aimed at the lower-cost consumer mass market rather than high-end audiophile niche markets only. CX-encoded records required a special CX expander connected to a stereo system, in order to fully reproduce the CX encoded sound on the LP. However, in contrast to dbx disc and High-Com II, CX-encoded records, like UC-encoded records, could also be played without a decoder with a resulting (claimed acceptable) amount of

dynamic range compression Dynamic range compression (DRC) or simply compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or ''compressing'' an audio signal's dynamic range. Compression is ...

. CX being a 2:1:2 compander system, a noise reduction of 20 dB(A) was achieved for a resulting maximum dynamic range of typically 80 to 85 dB(A) (other sources claiming up to 95 dB(A) or even 107 dB). The theory of operation is described in . The project was led by CBS Records group vice president Bob Jamieson and carried out by a team led by Daniel W. Gravereaux and Louis A. Abbagnaro. The label predicted that CX encoding would become standard on all new LP releases but this did not happen. CBS struggled to gain support for the system from other record companies. The process was controversial among CBS executives and unpopular with some artists. Classical guitarist

Liona Boyd Liona Maria Carolynne Boyd, (born 11 July 1949) is a classical guitarist often referred to as the First Lady of the Guitar. Music career Early years Boyd was born in London and grew up in Toronto. Her father grew up in Bilbao, Spain, and her ...

demanded that the CX encoded version of one of her albums be withdrawn because of perceived shortcomings, even though Jamieson claimed that CBS had the technical means to overcome such objections. Based on an UREI reference design published by CBS, many third-party builders of CX decoders used a dual

operational transconductance amplifier The operational transconductance amplifier (OTA) is an amplifier whose differential input voltage produces an output current. Thus, it is a voltage controlled current source (VCCS). There is usually an additional input for a current to control ...

''13700D'' made by JRC (today NJR), coupled with a pair of quadruple

JFET The junction-gate field-effect transistor (JFET) is one of the simplest types of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically controlled switches or resistors, or to build amplifier ...

operational amplifier An operational amplifier (often op amp or opamp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential (relative to ...

chips TL084 in their designs. Among them were

Telefunken Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the ''Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ('General electricity company'). The name "Telefunken" app ...

with their RN 100 CX, RS 120 CX and RS 220 CX. The documented playback time constants of the decoders were slightly changed by CBS in 1981/1982. In 1982, the CX integrated circuit U2141B was developed by AEG-Telefunken, Germany, by

Ernst F. Schröder The High Com (also as HIGH COM, both written with a thin space) noise reduction system was developed by Telefunken, Germany, in the 1970s as a high quality high compression analogue compander for audio recordings. High ...

, Dietrich Höppner and Kurt Hintzmann, the same team who previously designed the

High Com The High Com (also as HIGH COM, both written with a thin space) noise reduction system was developed by Telefunken, Germany, in the 1970s as a high quality high compression analogue compander for audio recordings. High Com ...

noise reduction system, a broadband compander with up to 20 dB of noise reduction.

Hitachi () is a Japanese multinational corporation, multinational Conglomerate (company), conglomerate corporation headquartered in Chiyoda, Tokyo, Japan. It is the parent company of the Hitachi Group (''Hitachi Gurūpu'') and had formed part of the Ni ...

also offered dedicated CX chips named HA12043 (for ''CX 14'') and HA12044 (for ''CX 20'') in 1983. Approximately 70 CX encoded LP titles were released by CBS up to 1983 in the United States. Gasparo also released a number of CX encoded records. In Europe, many CX discs were manufactured in the Netherlands with the catalog number prefix "CBSCX". The albums in this series also came in standard, non-CX encoded versions. A total of about 150 CX encoded titles exist. The implementation of a software decoder for CX is under consideration.

Use on LaserDisc and CED VideoDisc

While the implementation of CX with LPs was quite unsuccessful and short-lived, CX would later see success as the noise reduction used for the stereo analog audio tracks on the LaserDisc (LD) format. It was also used for the audio tracks on discs of the

RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent pool, patent trust owned by General Electric (GE), Westinghouse Electric Corporation, Westin ...

SelectaVision SelectaVision was a trademark name used on four classes of device by RCA: * The Holotape, a prototype video medium * Magnetic tape * VHS videocassette recorders, and * Capacitance Electronic Disc videodisc players and the discs themselves. C ...

CED Videodisc system. All LaserDisc (and stereophonic CED) players manufactured since 1981, when the CX equipped LD-1100 was introduced, had CX noise reduction capability as a standard feature. Pioneer also released a stand-alone CX adapter R-1000 for use with their VP-1000, Magnavox's VH-8000/8005 and the industrial players that were all released before CX was adopted. The first CX encoded LaserDisc was

Olivia Newton-John Dame Olivia Newton-John (26 September 1948 – 8 August 2022) was a British-Australian singer, actress and activist. She was a four-time Grammy Award winner whose music career included 15 top-ten singles, including 5 number-one singles on the ...

's '' Olivia Physical'' released by

MCA Videodisc Universal Pictures Home Entertainment (formerly Universal Studios Home Entertainment, Universal Studios Home Video, MCA/Universal Home Video, MCA Home Video, MCA Videodisc and MCA Videocassette, Inc.) is the home video distribution division of Am ...

. CX decoders made for LPs could not be used with LDs because the CX companding specifications for LaserDisc were changed, from 20 dB of noise reduction to 14 dB, along with moving the 'threshold' where compression/expansion changes from 2:1 to 1:1 from −40 dB to −28 dB - other minor changes to the decoding time constants were made as well. In addition, some of the LaserDisc's FM audio encoding specifications were modified too, allowing more headroom and better high frequency response at high levels. These changes were made because, at the time of CX's adoption on LaserDisc (1981), the vast majority of program sources used for mastering, such as 35 mm optical and magnetic film soundtracks, as well as the 2-inch IVC-9000 and the 1-inch C-Type video tape formats used for LaserDisc mastering, had signal-to-noise ratios low enough that ''undecoded'' playback would accentuate their noise to unacceptable levels. By reducing the total amount of noise reduction and modifying other aspects of the CX system to better match LD's FM audio shortcomings, undecoded playback sound quality was maintained and vastly improved decoded sound was achieved at the same time. The possibility of audible

pumping Pumping may refer to: * The operation of a pump, for moving a liquid from one location to another **The use of a breast pump for extraction of milk * Pumping (audio), a creative misuse of dynamic range compression * Pumping (computer systems), ...

breathing Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. All aerobic creatures need oxygen for cell ...

artifacts during CX decoded playback were reduced as well. While CX greatly improved the audio quality of LaserDisc's FM audio tracks, its primary reason for adoption was to decrease the amount of interference between the right channel's FM audio carrier and the video carrier's first chroma sideband. Without CX, strict filtering during mastering and playback as well as keeping color saturation below 75% on the master were required to keep any interference below −35 dB, which ensured that no beats or other artifacts were visible in the demodulated image. Although CX improved the picture quality, it was not normally used on discs with mono audio.

Pioneer Video Pioneer commonly refers to a settler who migrates to previously uninhabited or sparsely inhabited land. In the United States pioneer commonly refers to an American pioneer, a person in American history who migrated west to join in settling and de ...

, the main manufacturer of LDs at the time, required the studios to request CX and, since most did not know that CX improved the video quality of the finished discs or the audio of mono titles, CX was rarely requested. Due to this lack of knowledge about CX at the studios, there were many stereo titles released without CX encoding and, in fact, CX didn't become standard on all LaserDisc titles until the late 1980s. A look at Pioneer's catalogs as late as 1987 shows that the majority of titles did not have CX encoded analog sound - most were not digital either. For the CED VideoDisc, since stereo was not added to the format until its second year on the market, RCA made CX a mandatory part of CED's stereo system - a disc could not be released in stereo without CX encoding - and the companding specifications were unchanged from those of the LP system due to the CED system's much higher noise levels than the LaserDisc format. Although RCA improved the plastic/carbon formulation used to make discs, which lowered disc noise levels by 3 dB, and modified the mastering system, the CED format still required the full 20 dB of noise reduction that was achieved with the unmodified LP system. The names given by CBS to the two different versions of CX were CX-20 and CX-14.

Use in FM radio broadcasting

CX was used in FMX, a commercially unsuccessful noise reduction system developed in the 1980s for FM broadcasting in the United States. FMX was intended to improve fringe area reception of

FM stereo FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is cap ...

by adding a CX-encoded version of the L−R (left-minus-right, or difference) signal modulated in quadrature with the conventional stereo subcarrier. About 50 stations utilized the system, but few FMX-equipped receivers were manufactured, and after FMX was accused in 1989 of actually degrading reception rather than improving it, support dried up and the system was abandoned.

CX enabled equipment

These devices are known to support CX: * Backes & Müller CX Decoder * CBS CX Expander Model E-1016 *

CBS Technology Center CBS Laboratories or CBS Labs (later known as the CBS Technology Center or CTC) was the technology research and development organization of the CBS television network. Innovations developed at the labs included many groundbreaking broadcast, industr ...

CX Compandor Model 9101 * cm labs cm678 CX decoder *

Elektor :''Elektor (ἠλέκτωρ) is also an ancient Greek name or epithet of the Sun, see Helios.'' ''Elektor'', also known as ''Elektor Magazine'', is a monthly magazine about all aspects of electronics, originally published in the Netherlands as ' ...

CX decoders ( DIY projects based on the LM13700D/NE5517N and HA12044) * Kort Elektronik Dynamik Expander + CX Decoder SR * phase linear / aie CX Decoder Model 220 * Pioneer CX Decoder R-1000 (external CX 14 expander for LDs) * Popular Electronics / Phoenix Systems CX decoder by John Roberts (DIY project based on the CA3280) * Radio-Electronics CX decoder by Joel Cohen (DIY project based on the LM13700) *

Soundcraftsmen Soundcraftsmen was a manufacturer of high-end audio stereo components located in Santa Ana, California, United States. The company was founded in 1961 by Ralph Yeomans, a concessionaire in Fedco (a discount membership store chain in southern Cali ...

Preamplifier Model CX4000 * Soundcraftsmen Differential/Comparator Preamp-Equalizer Model CX4100 * Soundcraftsmen Differential/Comparator Preamp/Equalizer Model CX4200 *

RN 100 CX (external phono preamp with CX decoder based on LM13700) * Telefunken RS 120 CX (belt-drive record player with built-in preamp and CX decoder based on the NJM13700D) * Telefunken RS 220 CX (direct drive record player with built-in preamp and CX decoder) * Thorens PCX 975 by Heribert Heise (external phone preamp with CX decoder, claiming a dynamic range of up to 107 dB) * UREI CX Mastering Encoder/Decoder Model 1181 (switchable compander for CX 14 and CX 20 with half-speed mastering option based on Allison Research EGC-101, claiming a dynamic range of up to 95 dB(A)) * CX decoder by Markus Holtwiesche (DIY project based on the HA12044)

CX encoded vinyl records

The following vinyl records are known to have been produced in CX encoded editions: *

The Clash The Clash were an English rock music, rock band formed in London in 1976 who were key players in the original wave of British punk rock. Billed as "The Only Band That Matters", they also contributed to the and new wave music, new wave moveme ...

- ''

Sandinista! ''Sandinista!'' is the fourth studio album by the English punk rock band the Clash. It was released on 12 December 1980 as a triple album containing 36 tracks, with 6 songs on each side. It crosses various genres including funk, reggae, jazz, g ...

'' - Epic Records - 1980 * O.M.D. - ''

Orchestral Manoeuvres in the Dark Orchestral Manoeuvres in the Dark (OMD) are an English electronic band formed in Wirral, Merseyside, in 1978. The group consists of co-founders Andy McCluskey (vocals, bass guitar) and Paul Humphreys (keyboards, vocals), along with Martin ...

'' - Dindisc,

Virgin Records Virgin Records is a record label owned by Universal Music Group. It originally founded as a British independent record label in 1972 by entrepreneurs Richard Branson, Simon Draper, Nik Powell, and musician Tom Newman. It grew to be a worldw ...

, Epic Records FE37411 - 1981 *

- ''

Combat Rock ''Combat Rock'' is the fifth studio album by the English rock band the Clash. It was released on 14 May 1982 through CBS Records. In the United Kingdom, the album charted at number 2, spending 23 weeks in the UK charts and peaked at number 7 i ...

'' - Epic Records - 1982 *

Aaron Copland Aaron Copland (, ; November 14, 1900December 2, 1990) was an American composer, composition teacher, writer, and later a conductor of his own and other American music. Copland was referred to by his peers and critics as "the Dean of American Com ...

- ''Copland Conducts Copland'' - Columbia Records 33586 * Lacy J. Dalton - ''16th Avenue'' - Columbia Records 37975 *

Bob Dylan Bob Dylan (legally Robert Dylan, born Robert Allen Zimmerman, May 24, 1941) is an American singer-songwriter. Often regarded as one of the greatest songwriters of all time, Dylan has been a major figure in popular culture during a career sp ...

- '' Blood on the Tracks'' -

Columbia Records Columbia Records is an American record label owned by Sony Music, Sony Music Entertainment, a subsidiary of Sony Corporation of America, the North American division of Japanese Conglomerate (company), conglomerate Sony. It was founded on Janua ...

- (1982 re-issue) *

Terumasa Hino is a Japanese jazz trumpeter. He is considered one of Japan's finest jazz musicians. His instruments include the trumpet, cornet, and flügelhorn. Early life He was born in Tokyo, Japan, and his father was a trumpeter and tap dancer. Hino star ...

- ''Double Rainbow'' - Columbia CX 37420 *

Julio Iglesias Julio José Iglesias de la Cueva (; born 23 September 1943) is a Spanish singer, songwriter and former professional footballer. Iglesias is recognized as the most commercially successful Spanish singer in the world and one of the top record ...

- '' Momentos'' - CBS CX 25002 *

Billy Joel William Martin Joel (born May 9, 1949) is an American singer, pianist and songwriter. Commonly nicknamed the " Piano Man" after his album and signature song of the same name, he has led a commercially successful career as a solo artist since th ...

- ''

52nd Street 52nd Street is a -long one-way street traveling west to east across Midtown Manhattan, New York City. A short section of it was known as the city's center of jazz performance from the 1930s to the 1950s. Jazz center Following the repeal of P ...

'' - CBS CX 83181 *

- '' Glass Houses'' - Columbia Records 36384 *

- '' The Nylon Curtain'' - CBS CX 85959 * Charly McClain - ''Too Good To Hurry'' - Epic Records 38064 - 1982 *

Carole King Carole King Klein (born Carol Joan Klein; February 9, 1942) is an American singer, songwriter, and musician who has been active since 1958, initially as one of the staff songwriters at 1650 Broadway and later as a solo artist. Regarded as one o ...

- Tapestry - Epic/Ode Records PE 34946 *

Frank Marino Francesco Antonio Marino (born November 20, 1954) is a Canadian guitarist and singer, best known as the leader of Canadian hard rock band Mahogany Rush. Often compared to Jimi Hendrix, he is described as one of the most underrated guitarists ...

- ''

Juggernaut A juggernaut (), in current English usage, is a literal or metaphorical force regarded as merciless, destructive, and unstoppable. This English usage originated in the mid-nineteenth century and was adapted from the Sanskrit word Jagannath. ...

'' - Columbia CXAL 38023 *

Jimmy Cliff James Chambers OM (born 30 July 1944), known professionally as Jimmy Cliff, is a Jamaican ska, rocksteady, reggae and soul musician, multi-instrumentalist, singer, and actor. He is the only living reggae musician to hold the Order of Merit, t ...

- ''Special'' - CBS CX 85878 (1982) *

Johnny Mathis John Royce Mathis (born September 30, 1935) is an American singer of popular music. Starting his career with singles of standard music, he became highly popular as an album artist, with several dozen of his albums achieving gold or platinum s ...

- ''First 25 Years: Silver Anniversary Album'' - Columbia Records - (1981) *

Marty Robbins Martin David Robinson (September 26, 1925 – December 8, 1982), known professionally as Marty Robbins, was an American singer, songwriter, actor, multi-instrumentalist, and NASCAR racing driver. Robbins was one of the most popular and suc ...

- '' Come Back To Me'' - Columbia Records FC37995 - 1982 *

Men at Work Men at Work are an Australian rock band formed in Melbourne in 1978 and best known for breakthrough hits such as "Down Under", " Who Can It Be Now?", " Be Good Johnny", "Overkill", and " It's a Mistake". Its founding member and frontman is Col ...

- ''

Cargo Cargo consists of bulk goods conveyed by water, air, or land. In economics, freight is cargo that is transported at a freight rate for commercial gain. ''Cargo'' was originally a shipload but now covers all types of freight, including tran ...

'' - Columbia Records 38660 *

Randy Meisner Randall Herman Meisner (born March 8, 1946) is a retired American musician, singer, songwriter and founding member of the Eagles. Throughout his professional musical career, Meisner's main role was that of bassist and backing high-harmony vocal ...

- ''

'' - Epic Records - 1982 *

Pink Floyd Pink Floyd are an English rock band formed in London in 1965. Gaining an early following as one of the first British psychedelic groups, they were distinguished by their extended compositions, sonic experimentation, philosophical lyrics an ...

- ''

The Wall ''The Wall'' is the eleventh studio album by the English progressive rock band Pink Floyd, released on 30 November 1979 by Harvest/EMI and Columbia/ CBS Records. It is a rock opera that explores Pink, a jaded rock star whose eventual self-i ...

'' - Columbia Records 36183 * Freddie Salem & The Wildcats - ''Cat Dance'' - Epic Records 38018 - 1982 * Santana - '' Zebop!'' - Columbia CX PC 37158 - 1981 *

Saxon The Saxons ( la, Saxones, german: Sachsen, ang, Seaxan, osx, Sahson, nds, Sassen, nl, Saksen) were a group of Germanic * * * * peoples whose name was given in the early Middle Ages to a large country ( Old Saxony, la, Saxonia) near the No ...

- '' Strong Arm of the Law'' -

Carrere Carrere or Carrère may refer to: As a name * Georges Carrère (1897–1986), French classical violinist * Edward Carrere (1906–1984), Mexican art director * Emmanuel Carrère (1957–), French author, screenwriter, and director * Fernando Car ...

CXBL 537679 *

- '' Denim and Leather'' - Carrere CXAL 537685 *

Simon & Garfunkel Simon & Garfunkel were an American folk rock duo consisting of the singer-songwriter Paul Simon and the singer Art Garfunkel. They were one of the best-selling music groups of the 1960s, and their biggest hits—including the electric remix of ...

- '' Simon and Garfunkel's Greatest Hits'' - Columbia Records 31350 * The Sinceros - '' Pet Rock'' - 1981 * T.V. Smith's Explorers - ''The Last Words of the Great Explorer'' - Epic BL 37432 - 1981 *

Translator Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transla ...

- '' Heartbeats And Triggers'' - 415 Records/Columbia Records - 1982 * Deniece Williams - ''I'm So Proud'' -

- 1983 *

Ozzy Osbourne John Michael "Ozzy" Osbourne (born 3 December 1948) is an English singer, songwriter, and television personality. He rose to prominence during the 1970s as the lead vocalist of the heavy metal band Black Sabbath, during which period he adop ...

- '' Blizzard of Ozz'' - CBS Associated Records – Z 36812 - 1981

References

External links

* {{cite web , title=CX Encoder/Compander thread , language=de , date=2008-02-20 , url=http://www.analog-forum.de/wbboard/index.php?thread/41154-der-cx-expander-thread/ , access-date=2017-11-05 , url-status=live , archive-url=https://web.archive.org/web/20171105205113/http://www.analog-forum.de/wbboard/index.php?thread%2F41154-der-cx-expander-thread%2F , archive-date=2017-11-05 LaserDisc Sound recording Vinyl disc noise reduction systems

Use on vinyl LP records

Use on LaserDisc and CED VideoDisc

Use in FM radio broadcasting

CX enabled equipment

CX encoded vinyl records

See also

References

Further reading

External links