Speech and Audio Signal Processing: Processing and Perception of Speech and Music, Second Edition

CHAPTER 2

SYNTHETIC AUDIO: A BRIEF HISTORY

2.1 VON KEMPELEN

Many years ago, von Kempelen demonstrated that the speech-production system of the human being could be modeled. He showed this by building a mechanical contrivance that “talked.” The paper by Dudley and Tarnoczy [2] relates the history of von Kempelen's speaking machine. This device was built about 1780, at a time when the notion of building automata was quite popular. Von Kempelen also wrote a book [7] that dealt with the origin of speech, the human speech-production system, and his speaking machine. Thus, for over a century, an existence proof was established that one could indeed build a machine that spoke. (Von Kempelen's work brings to mind that of another great innovator, Babbage, who also labored for many years with mechanical contrivances to try to build a computing machine.)

Figure 2.1 shows the speaking machine built by Wheatstone that was based on von Kempelen's work. The resonator of leather was manipulated by the operator to try to copy the acoustic configuration of the vocal tract during the sonorant sounds (vowels, semivowels, glides, and nasals); the bellows provided the air stream; the vibrating reed produced the periodic pressure wave; and the various small whistles and levers shown controlled most of the consonants. (Much later, Riesz [6] built a mechanical speaking machine that was more precisely ...