"The first example of a real speech synthesizer appears in 1950 at Haskins Laboratories, with the PATTERN PLAYBACK. This machine can be considered as a sonagraph machine working in reverse. The sonagraph transforms recorded speech into a '3-dimensional' plot, the two first dimensions being time and frequency, the third one being intensity, represented on a gray scale. Conversely, by drawing schematic evolutions of formant frequencies on a glass plate, and by scanning this spectrogram along the time axis (using a set of frequency modulated light beams, and a light collector that is fed into a loudspeaker), one can actually hear the sound corresponding to the spectrogram."
Stella (1985, p. 425).
Listen to the pattern playback (AIFF).
The Pattern Playback still resides in the basement of Haskins Laboratories, in New Haven, Connecticut. You can make arrangements to visit it, but it is rarely turned on. However, additional sound examples and further background are provided on the Haskins Laboratories pattern playback webpage.
