RIAAhelisüsteemi

RIAAhelisüsteemi refers to the equalization curve standardized by the Recording Industry Association of America. This standard dictates how the frequency response of vinyl records is altered during both cutting (recording) and playback. The primary goal of the RIAA equalization is to improve the audio quality of vinyl records and make them more practical for mass production.

During the recording process, bass frequencies are attenuated (reduced in volume) and treble frequencies are boosted. This serves two main purposes. Attenuating the bass prevents the cutting stylus from jumping out of its groove and also reduces the amount of physical space required for bass frequencies on the record. Boosting the treble helps to overcome the inherent surface noise of vinyl, such as pops and crackles, making the quieter passages of music more audible.

During playback, a corresponding inverse equalization curve is applied by the phono preamplifier. This preamplifier boosts the bass frequencies that were attenuated during recording and attenuates the treble frequencies that were boosted. The net effect is a flat frequency response across the audible spectrum, as intended by the original recording, while simultaneously minimizing the impact of surface noise. The RIAA equalization curve was adopted in 1953 and has become the de facto standard for vinyl records worldwide.