What is GPVP General Processes of Voice Production (GPVP)

Three Processes

 Respiration
 Phonation
 Resonation

 The Pulmonary System

 Upper airway
 Laryngeal structures
 Lower airway (trachea, bronchial tubes, bronchioles & alveolar sacs)
 Thoracic cavity - thoracic vertebrae, ribcage, connecting muscles
Diaphragm muscle

 Respiratory Components of Voicing
 Airflow is essential for voice since:

·  Air is the medium for propagation of sounds

·   Air forced through constrictions along the respiratory tract generate sounds

 Two aspects of air important for generation of voice

·   Flow - volume of air passing through tube or duct per second

·   Pressure- force distributed over a surface

 Generation of Pressures/Flows
  Two ways of measuring pressure

·       Absolute pressure

·       Relative pressure

 Lung pressure

·       equivalent to alveolar pressure which is the pressure of air within the lung tissue

·       At resting level lung pressure equals atmospheric pressure

 Generation of Pressure & Flows

·       Flow begins when pressure within lungs is either above or below atmospheric pressure

·       Air flows from region of higher relative pressure (positive) to region of lower relative pressure (negative)

·       Inspiration - lung volume increases, lung pressure drops, air rushes in

·       Expiration - lung volume decreases, lung pressure increases, air flows out

 Muscles of Respiration

·       Inspiratory muscles - diaphragm, external intercostals & if necessary the shoulder and neck muscles

·       Expiratory muscles - 4 abdominal muscles and internal intercostals

·       Passive breathing - active contraction of inspiratory muscles followed by passive forces (elastic recoil of lung tissue, gravity, untorquing of ribs) that reduce lung volumes

·       To extend expiration - active contraction of muscles of expiration after passive forces dissipate

 Function of Larynx during Respiration

·        Larynx - specifically vocal folds function as a valve to regulate airflow

·      Vocal folds offer slight resitance to airflow

·      Glottis closes slightly for high lung pressures and opens wider for low lung pressures which helps keep pulmonary airflow more constant

·      This regulation autonomically controlled by nervous system

Lung Volume

Total Lung volume
Vital capacity - total amount of air that can beexpired after a maximum inhalation
Residual volume - air that remains in lungs after maximum exhalation

 Vital capcity

·       Tidal volume - amount of air breathed in and out during normal respiratory cycle -typically 10 - 15% of vital capacity

·       Inspiratory reserve - maximum air inhaled after tidal volume

·       Expiratory reserve - maximum air exhaled after tidal volume

 Variations in Respiration for Speech

·       Adducted vocal folds provide increased resistance to airflow

·       May need to activate abdominal muscles to get greater lung pressure

·       Also need to extend the expiratory phase

·       For longer phrases, will use more of active forces after passive forces are depleted

 Voice Disorders & Respiration

·       Goal is for respiratory patterns to be facilatory for vocalization

·       Best vocal quality associated with mid air-pressure and mid lung-volume levels

·       Teach shorter phrasing patterns to avoid low pressure and flow situations

·       Use increased abdominal contraction to increase power rather than tightening the laryngeal valve

 Process of Phonation

·      Production of voice is dependent on the interplay between muscular forces and aerodynamic events

·      Myoelastic-aerodynamic theory of vocal fold vibration

·      Contraction of intrinsic muscles determine the compliance, length, elasticity and mass of the vocal folds; also approximate vocal folds to phonatory position

·      Aerodynamic forces from build up of air pressure below the vocal folds force the adducted vocal folds open; Bernoulli effect aids muscular forces in closing vocal folds

 Mucosal Wave

·       Also important component of vocal fold vibration/voice production

·       Explained by Body-Cover model of vocal fold vibration

o   Different vibratory properties of vocal fold layers

o   Vertical phase difference

·       Loss of mucosal wave results in changes in voice quality, increases in PTP

·       Conditions that change density relationships between cover and body result in decreases in mucosal wave
 

 Modification of Fundamental Frequency

·       Determined by the vibratory rate (number of open/close cycles per second)

·       Perceived as the pitch of the voice

·       Rate of vibration related to thickness, length and elasticity of vocal folds

·       Increases in f0 also associated with increases in subglottal pressures, medial compression and glottal airflow rates
 

Vocal Registers

·       Defined by Hollien as range of consecutive f0s that can be produced with a perceptually distinct voice quality

·       Differ also with regard to laryngeal events such as vocal fold status, vibratory pattern, driving pressure and mean phonatory airflow

·       Three distinct speaking voice registers (singers identify more)

o   Pulse - lowest range of frequencies; glottal fry

o   Modal - most used register; more continuous tone than pulse

o   Loft - falsetto - upper frequencies; thin, maximally elongated folds

Modification of Vocal Intensity

·       Related to changes in subglottal and transglottal air pressure

·       Perceived as loudness changes

·       Average intensity during speech - 75 - 80 dB; dynamic range - 40 - 65dB

·       Modified by

o   Subglottal adjustments

o   Laryngeal adjustments

o   Supralaryngeal adjustments
 

Variations of Voice Quality

·       Way in which the laryngeal tone is initiated affects perceived voice quality

·       3 basic vocal or phonatory attacks

o   Simultaneous - exhalation and vocal fold approximation occur at same time

o   Hard glottal attack - vocal folds adducted tightly as exhalation begins

o   Breathy or aspirate attack - initiation of exhalation before adduction

·       Asynchronous movement of vocal folds affects quality

·       Supraglottal resonance variations - constriction, vertical & horizontal tone focus

 Resonance Components of Voice

·       Vibrating sound source excites air-filled chambers and walls of the chambers

·       Serves to selectively amplify vibrations

·       Most quality and loudness characteristics of human voice are a product of the resonating cavities

·       Resonance cavities can be altered in size, configuration & tightness
 

Structures of Resonance

·       Pharynx - 2 layers of muscles

o   Pharyngeal constrictors - outer layer

o   Stylopharyngeus, salpingopharyngeus & palatopharyngeus

·       Oral Cavity

·       Nasal Cavity

·       Velum

o   Levator palatini

o   Tensor palatini

o   Uvulus

o   Palatoglossus

o   Palatopharyngeus

 Modifications of Resonance

·       Coupling/uncoupling of nasal cavity

o   Velum elevates

o   Lateral walls of pharynx move medially

·       Tongue position changes size/shape of oral cavity

·       Ratio of oral to pharyngeal cavity

·       Membranes of pharynx and tightness of pharyngeal constrictors

 Effects of Aging on the Respiratory Mechanism

·       Decreases in vital capacity

·       Loss of elasticity in thoracic skeleton

·       Muscular weakness

·       Anecdotal reports of reduction in loudness in the elderly - not demonstrated objectively

 Effects of Aging on Laryngeal Mechanism

·       Cartilages calcify and ossify

·       Changes in cricoarytenoid joints limiting approximation of vocal folds

·       Changes/breakdowns in layers of the lamina propria

·       Laryngeal bowing - presbylaryngeus

 Functional Effects of Aging on the Voice

·       In 5th decade male fundamental increases, while female f0 decreases

·       Decline in pitch control

·       Reduction in pitch range

·       Perception of vocal roughness, aperiodicity and breathiness