The Transient Theory of Human Voice Production with Dr Julian Chen
Sunday 16th April 2023, 5:00 PM - 7:00 PM (London Time)
This event is free-to-attend as part of our World Voice Day celebrations.
In 1957, French physiologist Philippe Fabre invented the electroglottograph, which can accurately determine the closing and opening instants of the glottis in vivo. In 1984, Donald Miller and Harm Schutte further placed two pressure sensors immediately above and below the glottis, measured the air pressures across the glottis.
This experimental evidence enabled a scientific understanding of human voice production.
And so a refined version of the transient theory of human voice production, the timbron theory, initially proposed by Leonhard Euler in 1727, is established. In this lecture, experimental output and the timbron theory of human voice production are presented in an easy to understand graphical format.
Content:
According to that theory, the time between two adjacent glottal closing instants accurately defines the pitch period, and the sound waveform in each pitch period contains full information on the timbre. A method of extracting glottal closing instants from sound waves and a graphical display, the pitch-synchronous spectrogram, are presented.
Among the samples of human voice, the sound recordings of Luciano Pavarotti are analyzed. Some characteristics of the master singer are shown, and hints of how to improve the quality and volume of voice are presented.
Finally, the theory and parametrization method for human voice developed in early 20th century, the source-filter theory and linear prediction coefficients (LPC), are outlined.
Comparing with the more accurate timbron theory and pitch-synchronous parametrization method, the deficiencies of the source-filter theory and the LPC method are discussed.
Dr Julian Chen
Julian Chen received a PhD in Physics from Columbia University in 1985, then joined IBM Research Division as a Research Staff Member...
World Voice Day
World Voice Day takes place on 16th April annually. It is acknowledged across the globe, with the main goal being to increase awareness of voice and voice issues.
Sorry, this is an archived short course...
We have plenty of upcoming short courses coming soon. See details of some of them below or look at the full list of short courses.


Thursday 9th October 2025
2:00 PM - 4:00 PM
(London Time)
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As singers approach their senior years, they can benefit greatly from a voice teacher who understands the normal changes involved as they navigate vocal aging. This course will focus on the realities of aging voices for senior singers and what can be done to address vocal production and peripheral issues that can affect the activity of singing.


Friday 10th October 2025
3:00 PM - 5:00 PM
Monday 13th October 2025
3:00 PM - 5:00 PM
(London Time)
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Gökçe Kutsal
This course is designed to break down the fundamentals of acoustics for both spoken and sung voice in a beginner-friendly, accessible way — so you can easily understand and apply these concepts to your teaching or research.


Monday 13th October 2025
5:00 PM - 7:00 PM
(London Time)
Water Resistance Therapy and Semioccluded Devices for Voice Training

Dr Marco Guzmán
Several voice devices to perform water resistance therapy (WRT) and some oscillatory positive expiratory pressure devices (OPEP) (e.g. Acapella Choice, Shaker Medic Plus, New Shaker) are now commonly used for both voice training and voice therapy. Are these devices truly good for voice training? Are these devices the treatment by themselves? and how much evidence currently supports the use of these devices?