Presentation on theme: "The Human Voice Chapters 15 and 17. Main Vocal Organs Lungs Reservoir and energy source Larynx Vocal folds Cavities: pharynx, nasal, oral Air exits through."— Presentation transcript:
Main Vocal Organs Lungs Reservoir and energy source Larynx Vocal folds Cavities: pharynx, nasal, oral Air exits through nasal and oral cavities
Larynx Vocal folds (not really cords) Glottis Vocal folds act on air stream— Completely closed (stopping air and sound) Completely open (no sound—breathing) Slightly open (“h” sound) Rapid opening and closing, modulating the air stream)
Vocal Fold Vibration Rapid vibrations produce a buzzing sound Analogous to lips on a brass instrument Rate of vibration determined primarily by mass and tension (less so by air pressure and velocity) Adult males typically have longer folds with greate mass than females. Feedback from acoustic impedance has little effect.
Typical Vibration Frequencies 110 Hz in male 220 Hz in female 300 Hz in child Wide variations from one individual to another.
Vocal Tract Tube from vocal folds to lips, with side tract to nasal cavity. Length approx. 17 cm, slightly changeable by raising or lowering the pharynx, and by shaping the lips. Nasal cavity is approx. 12 cm, not changeable.
Vocal Tract (2) Oral Cavity: most flexible Size and shape variable by adjusting positions of palate, tongue, lips, and teeth. Mouth opening small compared to wavelength. Only important in regards to resonance freq.’s Mouth radiates more efficiently at higher f’s.
Voice Spectrum The waveform can be considered either to be a narrow triangle wave, or a pulse wave. Both produce a buzzing sound, with all harmonics of the fundamental frequency. Spectrum is product of three components: Speech sound = source x filter x radiation eff.
Resonances—Formants Frequency mainly determined by vocal folds. Peaks in sound spectra for different vowels Formants Independent of pitch
Resonance Frequencies for Vowels Fixed formant frequencies for each vowel. Spoken: Table 15.3, p. 346 Sung: Table 17.1, p. 378
Formant Tuning by Sopranos Changing the size of the mouth opening (lips and jaw) can change the tuning of formants. Necessary when fundamental pitch is above a formant. Also used to tune formants to match harmonics of fundamental pitch. Wider openings move formants higher in frequency. Vocal distortion not objectionable, except at very high pitch ranges.