CX (audio)

CX is a noise reduction system for recorded analog audio. It was developed by CBS Laboratories (a division of CBS) in the late 1970s as a competitor to other noise reduction (NR) systems such as Dolby and dbx, and was officially introduced in 1981. The name CX was derived from "Compatible eXpansion," a feature of the technique. The CX integrated circuit U2141B was developed by AEG-Telefunken, Germany, in 1982, by the same team who also designed the High Com noise reduction system, a broadband compander with typically up to 20 dB of noise reduction (and more).

CX was originally designed by CBS as a noise-reduction technology for vinyl LP records, similar to the earlier dbx system for dbx discs. CX required a special decoder connected to a stereo system, in order to fully reproduce the CX encoded sound on the LP. However, CX-encoded records could also be played without a decoder, with a resulting (claimed acceptable) amount of dynamic range compression. Relatively few hardware decoder boxes were sold.

The project was led by CBS Records group vice president Bob Jamieson and carried out by a team led by Dan Graveraux. 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 Classical guitarist Liona Boyd demanded that the CX encoded version of one of her albums be withdrawn because of perceived shortcomings, even though Jamieson claimed that CBS had the technical means to overcome such objections.

Approximately 70 CX encoded LP titles were released by CBS in 1982 in the United States. 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.

...
Wikipedia