Synthesis of disordered voices

The context of this project is the clinical assessment of voice. Auditory and acoustic assessment of voice (and by extension speech) is to laryngology and speech therapy what electrocardiography is to cardiology and electroencephalography to neurology. That is, it reports the function of the laryngeal oscillator and the adequacy of the produced vocal timbre by relying on methods of investigation that are not intrusive and do not obstruct the patient’s production of speech. Synthetic speech contributes to that purpose as a computational tool to facilitate tests and training, and also to explore and understand the genesis of abnormal vocal qualities.

Vocal tract

A disordered voice is a voice that is perceived as abnormal with regard to pitch, loudness or timbre, and is often the consequence of a laryngeal pathology or some physiological dysfunction. In this project, we develop a synthesizer of speech sounds which is capable of simulating the timbre of normal and disordered voices with an acceptable level of naturalness. We follow a physics-based strategy using models of the vocal fold vibration, glottal airflow and acoustic wave propagation in the vocal tract.

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  • The most recent version of the synthesizer is described in our poster in the 9th International Conference in Voice Physiology and Biomechanics (2014), avaliable on the same link above.

  • See also: J. C. Lucero, J. Schoentgen & M Behlau. “Physics-based synthesis of disordered voices”, Interspeech 2013 (Lyon, France, 2013). PDF.

  • The naturalness of the synthetic voices has been assessed in: M. Englert, G. Madazio, I. Gielow, J. C. Lucero & M. Behlau. “Perceptual error identification of human and synthesized voices”, Journal of Voice, in press. Info

  • For other publications, follow this link.

  • Results presented at meetings of the Brazilian Society of Phonoaudiology received a Prize for Excellence in 2013 and 2015.


Dr. Jean Schoentgen, Université Libre de Bruxelles, Belgium.
Dr. Mara Behlau, Center for Voice Studies and Federal University of São Paulo.
Dr. Glaucya Madazio, Center for Voice Studies, São Paulo.


Marina T. Englert, Master's course, Federal University of São Paulo.


Henrique Rodrigues Costa, undergraduate research student, 2015, University of Brasília.
Elias Amadeus, bachelor in Computer Science, 2015, University of Brasilia.