The UC compander system (with "UC" derived from Universal Compatible or Universal Compander) is a

noise reduction system 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 u ...

for

vinyl record A phonograph record (also known as a gramophone record, especially in British English) or a vinyl record (for later varieties only) is an analog signal, analog sound Recording medium, storage medium in the form of a flat disc with an inscribed, ...

s, aiming at highest playback compatibility even without corresponding UC expander.

Overview

The UC

compander In telecommunications and signal processing, companding (occasionally called compansion) is a method of mitigating the detrimental effects of a channel with limited dynamic range. The name is a portmanteau of the words compressing and expandi ...

system was developed in the 1980s by (ZWT) of (RFT) in the former

German Democratic Republic East Germany, officially known as the German Democratic Republic (GDR), was a country in Central Europe from Foundation of East Germany, its formation on 7 October 1949 until German reunification, its reunification with West Germany (FRG) on ...

(GDR). The system was based on the observation that the dynamic range of typical audio source material almost always needs to be reduced in the vinyl mastering process and that very similar system parameters are commonly applied in the process either by the sound engineer or through the hardware. The idea was to develop a

system loosely emulating this process and to formally standardize on its characteristics. By emulating the typical characteristics of this compression, UC compressed records would not produce acoustical artifacts which would not have been present in similar form on the produced disk anyway, and that thereby they would remain virtually unrecognizable, so that consumption would remain acoustically pleasing and compatible even if records were later played back without UC expander. Initial experiments with a compression factor of 2:1:2 were found to still cause too many artifacts to maintain this compatibility, which led the UC developers to implement a broadband compander utilizing an adaptive compression factor between 1.33:1:1.33 (or 1.67:1:1.67) (at 0 dB) and 1:1 (at −20 dB). In contrast to earlier vinyl disk noise reduction systems such as dbx disc, High-Com II or CX 20, the system deliberately limited the reduced disk noise by about 10 to 12 dB(A) only, an amount similar to what could be achieved by other compander systems where only the receiving side of the medium was exposed to users and therefore the system had to remain playback compatible with a large installed base of devices without corresponding decoder (such as Dolby FM or High Com FM in radio broadcasting). In fact, the results were found so good that, especially for records produced with

Direct Metal Mastering Direct metal mastering (DMM) is an analog audio disc mastering technique jointly developed by two German companies, Telefunken-Decca ( Teldec) and Georg Neumann GmbH, toward the end of the 20th century after having seen the same technology us ...

(DMM) (but not exclusively), the system was ''undocumentedly'' introduced into the market by the East-German through record labels such as

Amiga Amiga is a family of personal computers produced by Commodore International, Commodore from 1985 until the company's bankruptcy in 1994, with production by others afterward. The original model is one of a number of mid-1980s computers with 16-b ...

, and

Nova A nova ( novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new") that slowly fades over weeks or months. All observed novae involve white ...

since 1983/1984, with UC-encoded records only identifiable by a shy extra "U" engraving in the disk's silent inner groove area. Up to 1990, over 500 UC-encoded titles were produced. The economical necessities in the former GDR, however, made it impossible to introduce a suitable UC decoder at the same time. Prototypes of a HMK-D100-based

tape recorder An audio tape recorder, also known as a tape deck, tape player or tape machine or simply a tape recorder, is a sound recording and reproduction device that records and plays back sounds usually using magnetic tape for storage. In its present ...

with digital counter and UC expander seem to have existed in 1987. Finally, a UC expander was built into the Ziphona HMK-PA2223, a tangential arm direct drive turntable manufactured by in limited

zero batch Pre-production is the process of planning some of the elements involved in a film, television show, play, video game, or other performance, as distinct from production and post-production. Pre-production ends when the planning ends and the con ...

quantities only around 1989. The expander was based on a RFT/ HFO A274 the East-German equivalent to the voltage-controlled electronic

potentiometer A potentiometer is a three- terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. The measuring instrum ...

IC /

Philips Koninklijke Philips N.V. (), simply branded Philips, is a Dutch multinational health technology company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarter ...

TCA740 The

German reunification German reunification () was the process of re-establishing Germany as a single sovereign state, which began on 9 November 1989 and culminated on 3 October 1990 with the dissolution of the East Germany, German Democratic Republic and the int ...

and the advances in digital home audio equipment put an end to the further introduction of the system in 1990. Given the revival of vinyl records, the re-introduction of UC and the development of corresponding compander hardware based on modern semiconductors has been considered several times around 1994/1995 and 2009/2010. A software decoder for UC has been implemented.

Overview

See also

Notes

References

Further reading