Accidentals.

James Kaplan describes the day "So What" was recorded ...

“Miles, where are you gonna work now?” he asked. The producer was referring to Davis’s position in relation to the microphone, from which he had apparently stepped back momentarily.

“Right here,” Miles said.

“When I play it I’m gonna raise my horn a little bit,” Miles said. His customary playing stance, onstage or in the recording studio, was to point his trumpet straight at the floor as he played, a position that communicated contemplation and moodiness, though it was primarily a way of regulating his tone. “Can I move this down a little bit?” He indicated the mike.

“It’s against policy to move a microphone,” Townsend said, deadpan. The old church echoed with laughter.

Outside the 30th Street Studio, Manhattan was Manhattaning: rounded buses and big yellow cabs grinding up and down the avenues; car horns and scraps of radio music and pedestrians’ voices echoing in the deep-shadowed side streets. Outside, the everyday clamor and clash of a city afternoon in late-winter 1959; inside, the densest quiet as a passage outside of time proceeded: the recording of CO 62291, the number that would come to be titled “So What,” leading off the album soon to be known as Kind of Blue.

The first take began. There was a false start of four seconds, followed by an incomplete take of forty-nine seconds. Townsend interrupted from the booth: something was interfering with the song’s profound hush. “Hold it,” the producer said. “Sorry—listen, we gotta watch it because, ah, there’s noises all the way through this. This is so quiet to begin with, and every click—watch the snare too, we’re picking up some of the vibrations on it—”

Miles, ever on the lookout for meaningful accidentals, demurred. “Well, that goes with it,” he said. “All that goes with it.”

“All right,” Townsend allowed. “Not all the other noises, though . . .”

Another false start, seventeen seconds. An incomplete take, a minute eleven. A telephone rang in the control booth. Once quiet was restored, three more false starts, of sixteen, seven, and fifteen seconds.

Then, history.