six approaches toward a tone that was always sounding.
the last one gets close enough that the air starts to beat. close is a sound.
composing offline…
horizontal line = the door tone (A4, 440 Hz), patient, always there ·
climbing columns = the approaches, each topping out closer ·
the long thick band at the end = 437 Hz against 440: a 3 Hz beat, the sound of almost.