Throw on any iconic rock album from the mid-1970’s to early 1980’s, and chances are, you’ll hear the distinct sound of pitch-shifting and harmonizing effects that were just beginning to revolutionize how records were being produced — from the rhythm instruments on David Bowie’s 1975 album “Young Americans”, to the arena-sized choruses of AC/DC’s “Back In Black”, to the signature double-tracked tones of Eddie Van Halen’s finger-blistering guitar work in his band’s 1978 debut album, “Van Halen”.
An important genesis of that sound would first make its waves in the basement of Sound Exchange recording studio on West 54th Street…