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Contents Chapter 8

Speech synthesis demo

Speech sounds can be minimally specified in terms of a small set of parameters (variables), each of which can be described in terms of how they sound (their auditory characteristics), how they are made (physiological characteristics), or their physical (acoustic) characteristics.

This speech was synthesized in 1971 by Peter Ladefoged on a synthesizer at UCLA. The values of the parameters were a modified version of a set provided by John Holmes.

1 Pitch of voice Rate of vibration of the vocal folds Fundamental frequency
2 Overtone pitch (1) First resonance of the vocal tract Formant 1 frequency
3 Loudness of overtone (1) Formant 1 amplitude
4 Overtone pitch (2) Second resonance of the vocal tract Formant 2 frequency
5 Loudness of overtone (2) Formant 2 amplitude
6 Overtone pitch (3) Third resonance of the vocal tract Formant 3 frequency
7 Loudness of overtone (3) Formant 3 amplitude
8 Pitch of noise Fricative and stop bursts Center of noise frequency
9 Loudness of noise Amplitude of noise

The 8 links below demonstrate how speech can be built up using these parameters and additional (fixed) higher formants.

Formant 1 alone (parameters 2 and 3 above)

Formant 2 alone (parameters 4 and 5 above)

Formant 3 alone (parameters 6 and 7 above)

Formants 1, 2 and 3 (parameters 2 - 7 above)

Formants 1, 2 and 3 plus additional overtones (parameters 2 - 7 above plus fixed overtones)

Fricative and burst noises alone (parameters 8 and 9)

Everything except the fundamental frequency (parameters 2-9)

Everything including the fundamental frequency (parameters 1-9)