What are Phono EQ Curves?

Phono equalization (EQ) curves are correction standards that adjust the frequency characteristics of sound signals during recording and playback. The Recording Industry Association of America (RIAA) established the RIAA equalization curve as a standard for recording and playing phonograph records. The curve is used to improve sound quality, extend recording times, and reduce groove damage. 

The RIAA curve uses a recording process that reduces low frequencies by 20 decibels (dB) and increases high frequencies by 20 dB. This process creates smaller grooves for low frequencies, which makes them easier for the phonograph's cartridge to play back. It also allows for more songs per side of a record. Playback devices use the inverse of the recording curve to restore the audio to its intended sound. This process involves increasing high frequencies by 20 dB and decreasing bass levels by the same amount, for a total equalization of 40 dB. The EQ is then reversed to present the music flat again.