Dynagroove is a recording process introduced in 1963 by RCA Victor that, for the first time, used analog computers to modify the audio signal used to produce master discs for LPs.
The intent was to boost bass on quiet passages, and reduce the high-frequency tracing burdens (distortion) for the less-compliant, "ball" or spherical-tipped playback cartridges then in use.
But, because the changes were multiple (bass, treble, dynamic range) and algorithmic (thresholds, gain curves), RCA justifiably referred to the analog device as a computer.
RCA claimed that Dynagroove had the effect of adding brilliance and clarity, realistic presence, full-bodied tone and virtually eliminated surface noise and inner groove distortion.
Holt, a noted audio engineer and writer of the 1960s and 1970s, slammed Dynagroove as introducing "pre-distortion" into the mastering process, making the records sound worse if they were played on high-quality phono systems.