“Echoes” grew from that note into something awesome: a 23-minute psych-prog voyage from tranquility to triumph to desolation and back, with a riff like a lightning bolt striking open sea, and a pillowy lead vocal keeping you cozy and safe below deck. So they used the demo tape, and began composing around it. “We could never recreate the feeling of this note in the studio, especially the particular resonance between the piano and the Leslie,” drummer Nick Mason wrote later. It was piercing, but slightly obscured, as if it had traveled a great distance to reach your awareness. They called the results “Nothings 1-24”: Predictably, they were almost entirely unusable-except for this one note: a high B, played on a piano near the top of its range, warped by the undulations of a rotating Leslie speaker.

They spent weeks improvising with each member isolated from what the others were playing-a harebrained search for the sort of strange and spontaneous inspiration that their old leader, guitarist and songwriter Syd Barrett, conjured freely. Pink Floyd had no new songs prepared when they started recording in early 1971, but they did have access to the legendary Abbey Road Studios, and free rein from their label to mess around until they found their way.

It was a single note, flickering out like a beacon to lead a wayward ship through the night.

Today, we revisit Pink Floyd’s conflicted and brilliant album from 1971. Each Sunday, Pitchfork takes an in-depth look at a significant album from the past, and any record not in our archives is eligible.

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