RIAA equalization is a specification for the recording and playback of phonograph records, established by the Recording Industry Association of America (RIAA). The purposes of the equalization are to permit greater recording times, improve sound quality, and to reduce the groove damage that would otherwise arise during playback.
The RIAA equalization curve was intended to operate as a de facto global industry standard for records since 1954. However, it is almost impossible to say when the change actually took place.
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.
Read more about RIAA Equalization: The RIAA Curve, The Enhanced RIAA Curve, IEC RIAA Curve, TELDEC/DIN Curve, References