1	RESONATING YOUR VOCAL TRACT TO MATCH YOUR PITCH Ingo R Titze Executive Director, National Center for Voice and Speech The Denver Center for the Performing Arts Distinguished Professor of Speech Science and Voice Speech Pathology and Audiology and the School of Music The University of Iowa
2	Definitions of Resonance Resonance is a reinforcement of a natural behavior or phenomenon Acoustic resonance is an intensification of sound by sympathetic vibration of two or more things Vocal tract resonance is a selective reinforcement of a few source (larynx) frequencies by the vocal tract
3	Definitions of a filter A filter allows some items to pass while rejecting other items (e.g., a smoke filter, a sand filter) An acoustic filter allows some frequencies to pass while rejecting others The vocal tract can be thought of as a filter because it resonates (reinforces and transmits) some frequencies while rejecting others Hence: filter = resonator
4	The Source-Filter Theory of Vowels is Based on Resonance Linear theory – source is independent of filter (vocal tract) and filter resonates frequencies of the source Nonlinear theory – source frequencies depends on filter (vocal tract) and filter can both modify and resonate the source
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20	Brasses and woodwinds Have long tubes, which keep the resonances at low frequencies, near the source frequencies (harmonics) Have sharply tuned resonances Keep over 90% of the acoustic energy inside the tube, which helps the lips or the reed in vibration
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22	In singing, we cannot resonate all source frequencies with the vocal tract because: The vocal tract is too short, meaning that the resonances are spread too far apart We need to move the resonances around to make vowels and consonants
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25	To get the maximum boost from the vocal tract we can either: Resonate one or two harmonics of the source selectively (as in harmonic singing, counter-tenor singing, high coloratura, or whistle voice), or Resonate the entire vocal fold vibration process with a vocal tract that stores and returns energy to the glottis
26	The two choices are described by: Linear source-filter acoustics, for which the source is independent of the vocal tract Nonlinear source-filter acoustics, for which the source is interactive with the vocal tract
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36	Inertive Reactance = (inertance) x (frequency) Inertive reactance measures the amount of acoustic energy stored in the vocal tract, and It also determines the amount of energy fed back to the glottis to help the vocal folds vibrate
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39	Inertive reactance: Skews the flow pulse, Which increases the maximum flow declination rate (MFDR) Which increases the vocal intensity
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42	Semi-occluded vocal tract exercises for vocal warm-up and training mixed register Phonation into straws Bilabial fricative Lip trills tongue trills lip-tongue trills (raspberry, or razz) humming
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44	What semi-occluded vocal tract exercises accomplish They maintain a positive supraglottal pressure, which raises the intraglottal pressure, which keeps the vocal folds slightly abducted under high lung pressures They compel the vocalist to lower the threshold pressure by “squaring up” the vocal folds They lower F1 to give the vocalist the benefit of inertive reactance over the entire pitch range They allow pitch and lung pressure to be raised to high levels without excessive vocal fold collision
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51	Conclusion 1 With a wide-open mouth (megaphone shape), a male sound or a female belt sound can be produced as long as F1 is above the second harmonic With a wide-open mouth (megaphone shape), a male counter-tenor sound or a female classical lyric or coloratura sound can be produced as long as F1 is above the fundamental
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57	Conclusion 2 With a small mouth opening (inverted megaphone shape), a mixed-register male or female sound can be produced as long as F2 is higher than the second harmonic With a small mouth opening (inverted megaphone shape), a male counter-tenor sound or a female classical lyric or coloratura sound can be produced as long as F2 is higher than the fundamental
58	Overall Conclusion In singing, the source (larynx) can be highly interactive with the vocal tract Interaction is heightened if some part of the vocal tract is narrow, such as the epilarynx tube; this creates not only vocal ring, but higher overall intensity A semi-occluded vocal tract (at the mouth) is very friendly to a mixed register and hence is very useful for training classical singing
59	The End (Questions ?)