We tried to record the acoustic signature of a door that has never existed.
// objective
Capture the sound of a closing door in a hallway that contains no doors.
// method
A condenser microphone was placed facing nothing in particular. We waited. Coffee was consumed. We waited a little longer.
// observation
At exactly 03:33, the waveform produced a shape resembling footsteps. There are no feet in this facility. The peak frequency was 9 Hz.
// result
Inconclusive. The microphone has been retired and now refuses to record silence.