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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 nasal and oral cavities. Larynx . Vocal folds (not really cords) Glottis Vocal folds act on air stream—
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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 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.