Pattern Playback: Sentences - Never kill a snake.
“Never kill a snake” spectrogram (3 versions)
This sample sound file (from August 1958 — see spectrogram, above) contains three versions of “Never kill a snake.”
(a) by transmission
(b) by reflection (a hand copy with fine structure preserved)
(c) by reflection (a hand copy which has been simplified and schematized).
By Transmission
The Pattern Playback can convert spectrograms into sound. In one form of operation (transmission), a negative is made from a sound spectrogram so that regions occupied by sound are now transparent. Modulated light passed through these regions is picked up by the light collector and amplified.
By Reflection
To hand-copy a spectrogram, a clear sheet of plastic is placed over the spectrogram. Those regions that contain sound in the original are copied over with white paint. The light collector on the Pattern Playback now picks up only those frequencies that are reflected by the white paint.
Negative of a spectrogram of the sentence fragment “Never kill a snake” (top) and a schematic copy for input to the Pattern Playback (bottom). (Note: Thanks to Steve Witham for aligning the annotation at the bottom of this figure with the spectrogram negative and schematic copy shown above.)