RIAAequalization

RIAA equalization is the standard curve used in the mastering and playback of vinyl records. It defines a matching pre-emphasis during recording and de-emphasis during playback, so that the overall system response is approximately flat. The standard was introduced by the Recording Industry Association of America in the 1950s and became the de facto global standard for vinyl. It is implemented with a specific three-segment equalization network defined by three breakpoints at roughly 50 Hz, 500 Hz, and 2120 Hz, corresponding to time constants of 3180 µs, 318 µs, and 75 µs. During recording, the signal is shaped by the RIAA curve; during playback, a matching inverse curve in the phono preamplifier applies de-emphasis to restore amplification and tonal balance. The result is a flat frequency response across playback when used with compatible equipment. Variations such as NAB and CCIR were used in other media and predate the RIAA standard. In modern practice, vinyl mastering uses the RIAA curve; most phono stages provide RIAA equalization, and digital systems implement it in software or DSP for accurate archival playback.