What is the RIAA Equalization Curve?
Since the 1960’s, everything recorded to vinyl when the lathe master is cut is run through an analog process which produces frequencies that fit what the Recording Industry Association of America’s ” RIAA Equalization Curve”, introduced as a standard in 1954, which is still used today in recording to vinyl and in phono pre-amps for playing back records. To quote from the Wikipedia: RIAA equalization is a form of preemphasis on recording, and deemphasis on playback. A record is cut with the low frequencies reduced and the high frequencies boosted, and on playback the opposite occurs. The result is a flat frequency response, but with noise such as hiss and clicks arising from the surface of the medium itself much attenuated. The other main benefit of the system is that low frequencies, which would otherwise cause the cutter to make large excursions when cutting a groove, are much reduced, so grooves are smaller and more can be fitted in a given surface area, yielding longer playback time
