Dynagroove

This is scanned from a 1963 compilation of Hank Snow songs. The record was terrible and destined for the circular file. then I saw the magic words in the print on the back:

"To solve these old and obstinate problems in disc recording, highly ingenious computers—"electronic brains"— have been introduced to audio for the first time. These remarkable new electronic devices and processes grew out of an intense research program which produced notable advances in virtually every step of the recording science."

Despite the description they were not recorded to hard drives, they were recorded to tape. What dynagroove did was to modify the audio signal to better conform to a groove the stylus would later have to play back. It was a basic limiter/compressor. A quick listen to hank confirmed that for me the amplitude was pretty constant and the bass and treble clearly being manipulated. Audiophile magazines of the day panned Dynagroove and the process was discontinued in the 1970s.