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

vinyl record A phonograph record (also known as a gramophone record, especially in British English), or simply a record, is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts near ...

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

Overview

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

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(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 compander 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 acoustical 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 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 ...

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

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, and

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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 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. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters is ...

TCA740 The

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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