Public Release:  Voice prostheses can help patients regain their lost voice

Academy of Finland



Besides in speech synthesis, inverse filtering is needed in automatic speech recognition. In speech synthesis, a computer will transform text into synthetic speech. The old-fashioned way is to record individual words and play them one after the other, but this seldom produces natural-sounding speech.

"Most speech sounds are a result of a specific process. The air flowing between the vocal folds makes them vibrate. This vibration, if we could hear it, would produce a weird buzzing sound. However, as it moves through the vocal tract, that buzz is transformed into some familiar vowel," explains Siltanen.

Singing, says Siltanen, is a perfect example of this interplay between the vocal cord response and the vocal tract: "When we sing the vowel 'a' in different pitches, our vocal tracts remain unchanged but the frequency of the vocal cord excitation changes. On the other hand, we can also sing different vowels in the same pitch, whereby the shape of the tract changes and the excitation stays the same."



More information:

Professor Samuli Siltanen, Department of Mathematics and Statistics, University of Helsinki, tel. +358 9 191 51420 or +358 40 594 3560,

Harri Auvinen, Tuomo Raitio, Samuli Siltanen, Paavo Alku: Utilizing Markov Chain Monte Carlo (MCMC) Method for Improved Glottal Inverse Filtering, to appear in the proceedings of InterSpeech 2012 conference, Portland, Oregon, USA, 9 Sep 2012.

Tuomo Raitio, Antti Suni, Hannu Pulakka, Martti Vainio, Paavo Alku: Utilizing glottal source pulse library for generating improved excitation signal for HMM-based speech synthesis. In CD Proceedings of the International Conference on Acoustics, Speech, and Signal Processing (ICASSP'11), Prague, Czech Republic, 22 May 2011.

Academy of Finland Communications
Communications Specialist Leena Vähäkylä
Tel. +358 29 533 5139
