In 1991, record producer Johnny Sandlin stood in front of the Georgia Theatre in downtown Athens, Georgia. He was asked by an interviewer about rising Athens rock act Widespread Panic, with whom Sandlin was working on the band’s self-titled album.

“There’s a trend of getting back to real music now, played by real people,” Sandlin said. “The [1980s] seemed to be so computerized, where technology took over the music. And now, it’s getting back in the hands of the musicians and the players — the way it should be, the...