Phonation Flashcards
Larynx
The Voice-box
Complex organ in the anterior neck
Cartilage, muscle, fat, connective tissue, bone
Works in concert with lungs & oral/nasal cavities to produce voice
Functions of Respiratory System
Respiration (breathing)
Provision of airway
Protection of airway
Deglutation (swallowing)
Closure of larynx
Cessation of breathing
Phonation (voice)
Vibrating airstream and elements
Laryngeal Muscles
Intrinsic (inside larynx)
Abduction (opening)
Adduction (closing)
Tension
Extrinsic (outside larynx)
Position of larynx in neck
Infrahyoid (below)
Suprahyoid (above)
Resonator
Above vocal folds
Supraglottic vocal tract
Oscillator
Vocal folds
Elastic, pliability properties
Power Source
Below vocal folds
Infraglottic vocal tract
Phonation
Rapid (vibratory) opening/closing of vocal folds
Interrupts stream of air
Series of air puffs
Rippling displacement of vocal fold cover
(Mucosal wave)
Produces a vocal tone
Myoelastic aerodynamic theory
Bernoulli Effect
When a gas flows through a constricted passage, the velocity increases
Inward pressure is > the outward pressure
Walls are drawn into each other
Controls the closing of VF
Myoelastic Aerodynamic Theory
Drives the vibratory cycle of the vocal folds
The myoelastic theory states that when the vocal cords are brought together and breath pressure is applied to them, the cords remain closed until the pressure beneath them—the subglottic pressure—is sufficient to push them apart, allowing air to escape and reducing the pressure enough for the muscle tension recoil to pull the folds back together again. Pressure builds up once again until the cords are pushed apart, and the whole cycle keeps repeating itself. The rate at which the cords open and close—the number of cycles per second—determines the pitch of the phonation.
Voicing
Each vibration of the VF allows a brief puff of air to escape producing an audible sound at the frequency of the opening.
Vocal Sound Production Process
Diaphragm action pushes air from the lungs through the vocal folds, producing a periodic train of air pulses.
This pulse train is shaped by the resonances of the vocal tract.
The basic resonances, called vocal formants, can be changed by the action of the articulators to produce distinguishable voice sounds, like the vowel sounds.
VF Vibratory Process
Subglottic air pressure builds up to separate the folds
The sudden drop in pressure pulls the cords together
Air rushes through the glottis at increased velocity
As the top of the folds are opening, the bottom of the folds is closing
This creates a wavelike motion (mucosal wave)
Fundamental Frequency
The number of times the vocal folds are blown apart and come together per second
Directly related to the length, mass and tension of the vocal folds
The repetition rate of a complex periodic wave
When speaking or singing there is always an underlying note to each sound
Pitch is defined as the average rate of vocal fold vibration and is measured in cycles per second or Hertz
For pitch to rise, the VF must vibrate more quickly. They get thinner by being stretched longer.
Pitch
Equal to Frequency: Number of cycles per second, Measured in hertz (Hz)
Fundamental frequency (F0)
Male: 100-150 Hz
Female: 180-250 Hz
(“middle C” on piano scale = 256Hz; octave higher = 512Hz)
Generally increases as vocal folds are thinned and stretched and pressure increases
Intensity of the Voice
Intensity (loudness) is the size of the sound wave
Increasing subglottal air pressure increases vocal intensity
Increased vocal intensity results from greater resistance by the vocal folds to the increased airflow
The folds don’t open any further than usual, but they stay closed longer, creating more distinct “puffs of air”
The VF are pressed together more firmly
Articulation affects the potential pressure difference