Sgt. Pepper's Lonely Hearts Club Band

Sgt. Pepper’s (1967) ended “rock as a live band captured on tape” and inaugurated “rock as studio composition.” George Martin and Geoff Emerick — Emerick had taken over as chief engineer at nineteen for Revolver the year before — used the four-track at Abbey Road to do things with no precedent as popular music technique: varispeed manipulation, artificial double tracking (invented by Ken Townsend at Abbey Road for Revolver and used extensively here), reverse tape effects, calliope tape loops built from spliced sections on “Mr. Kite,” and the orchestral crescendo on “A Day in the Life” achieved by giving the musicians the lowest and highest possible notes for their instruments and asking them to improvise between them over 24 bars.

The studio became the instrument — that is the specific idea this record introduced into popular music. The line from this to Brian Eno’s explicit theorisation of the studio as a compositional tool is direct. And from Eno to Madlib treating his SP-303 as an instrument rather than a sampler is the same line extended. The chain is longer than it looks, and this is one of its early points.