Semi-Occluded Vocal Tract Exercises with Dr. Ingo Titze

Semi-occluded vocal tract exercises have a long history. They include lip trills, tongue trills, straw or tube phonation, bilabial fricatives, nasals, and relatively closed vowels like /o/ and /u/.  For many years it has been known that phonation with a nearly closed mouth facilitates vocal fold vibration, but the science behind this facilitation has been a mystery. Feedback between the source and the filter has been successful in elucidating several phenomena regarding phonation with a semi-occluded vocal tract. First, a steady oral pressure helps to posture the vocal folds in an optimum position. Second, the increased inertance of the supraglottal vocal tract lowers the phonation threshold pressure, thereby making it easier for the vocal folds to self-oscillate. Third, vocal fold collision is reduced and a mixed registration is facilitated. Fourth, the small oscillation allows fundamental frequency to be taken very high in pitch glides to stretch the vocal ligament. Fifth, increase in lung pressure, which normally tends to produce a greater closed quotient, automatically spreads the vocal folds apart to maintain register balance. This presentation provides basic science explanations and data underlying these phenomena.

About the Presenter

Ingo R. Titze is a University of Iowa Foundation Distinguished Professor in the Department of Communication Sciences and Disorders and the School of Music. He also directs the National Center for Voice and Speech at the University of Utah. Although formally educated as a physicist (Ph.D.) and engineer (M.S.E.E.), Dr. Titze has applied his scientific knowledge to a lifelong love of clinical voice and vocal music.  Specifically, his research interests include biomechanics of human tissues, acoustic phonetics, speech science, voice disorders, professional voice production, and the computer simulation of voice. Dr. Titze has published over 350 articles in scientific and educational journals, authored books entitled Principles of Voice Production, The Myoelastic-Aerodynamic Theory of Phonation, Vocology:The Science and Practice of Voice Habilitation, and most recently, Fascinations with the Human Voice. Dr. Titze has administered and taught in the Summer Vocology Institute for 16 years. He currently serves as president of the Pan American Vocology Association.