Before then, especially from 1940, each record company applied its own equalization; there were over 100 combinations of turnover and rolloff frequencies in use, the main ones being Columbia-78, Decca-U.S., European (various), Victor-78 (various), Associated, BBC, NAB, Orthacoustic, World, Columbia LP, FFRR-78 and microgroove, and AES.
Inden da, især fra 1940, anvendte hvert pladeselskab sin egen udligning; der var over 100 kombinationer af frekvenskombinationer i brug, hvor de vigtigste er Columbia-78, Decca-US, Europæisk (diverse), Victor-78 (diverse), Associated, BBC, NAB, Orthacoustic, Verden, Columbia LP, FFRR-78 og Microgroove, og AES.