Phonatory Mechanisms Flashcards
Phonation
Also called Voicing - occurs very quickly
Phonation is the sound that is produced at the level of the larynx
The vocal folds (vf) are responsible for producing phonation or voicing
Valving
The vocal folds produce voicing by valving the air stream that flows through the larynx from the lungs
Valving is the abduction (open) and adduction (close) of the vocal folds
When the vocal folds valve the air stream, air will flow through the glottis in bursts
During speech, the vocal folds are ?
In an adducted or partially adducted state
The vocal folds do not have to be completely adducted in order to produce voicing
Voicing requires
both muscular and aerodynamic forces
Phonation Phases
1) PREPHONATORY phase
- vocal fold approximation
- medial compression
2) ATTACK Phase
- bernoulli effect
- initiation of phonation
- types of vocal attacks
prephonatory phase
- vocal folds move from an abducted to an adducted or partially adducted state
- duration of this phase varies with the phrase length
- vocal folds do not have to complete adduct in the Prephonatory Phase
Muscular force in the prephonatory phase
muscular force is used to adduct the vocal folds
Lateral cricoarytenoid + interarytenoids (transverse + oblique) are the PRIMARY muscles of ADDUCTION
Vocal Fold Approximation
The movement of the folds toward the midline
As the folds approximate, they do not always make complete contact
However, they will make partial contact
Approximation requires the use of ADDUCTOR MUSCLES
Approximation requires the use of what muscles
ADDUCTOR MUSCLES
Midline
An imaginary line in the center of the vocal folds. As the vocal folds adduct, they move towards midline
Medial Compression
The extent to which the vocal folds are approximated
The vocal folds are pressed together at midline; however, they do not have to completely adduct along their length
Medial compression of the folds is achieved by the ADDUCTOR muscles
Medial Compression achieved by which muscles ?
ADDUCTOR MUSCLES
Attack Phase
Begins with the vocal folds adducted or partially adducted
Occurs throughout the vibratory cycle
As with the prephonatory phase, the duration of the Attack Phase will also vary with phrase length
Bernoulli Effect or Bernoulli Principle
Aerodynamic law that explains how the vocal folds actually vibrate
Bernoulli Effect Explained
If the volumed of the air flow is constant, then the velocity of this air flow will increase when it reaches a point of constriction
At the point of constriction, the pressure of the flow will decrease
AKA
Vocal folds provide a source of constriction in the vocal tract. Without them, air would pass through unobstructed
The constriction produced by the vocal folds will cause the air flowing through the folds to increase in velocity
Think of the trachea as a tube. The larynx is situated superiorly to the trachea. The vocal folds are housed within the larynx. The folds serve as a point of constriction as they valve the air stream that is emitted by the lungs.
Initiation of Phonation
1) To begin phonation, you use the adductor muscles to draw the folds toward the midline
2) As the folds move towards midline, subglottal pressure increases
3) Subglottal pressure is the pressure of the air below the level of the folds. It’s generated by the lungs
4) As the folds approach midline, air flowing through the glottal chink will increase in velocity. The glottal chink is simply an opening in the vocal folds
5) The increase in velocity of air flowing through the glottis will create a negative pressure along the medial edges of the vocal folds
[Bernoulli effect begins here]
6) This negative pressure causes the folds to be drawn together [B effect continues]
7) With the folds completely adducted, the subglottal pressure increases
8) When this pressure reaches a critical level, the folds will be blown apart and voicing will begin
Voicing will continue until…
A. You run out of air, or
B. You finish talking, and then
C. Use what muscles to open the vocal folds?
posterior cricoarytenoid muscle
A cycle of VF Vibration
Vf vibration is expressed in (Hz) or Frequency
Frequency or Hz is the number of cycles per second that the folds vibrate. This number will vary by gender, age, + disease
Typical values for vocal fold vibration:
Adult Male: 150-190 Hz
Adult Female: 180-220 Hz
Child: 225-450 Hz (Infant to about age 12)
Types of Vocal Attacks (3)
Vocal attacks are defined as the way in which respiration and the laryngeal systems are coordinated
1) SIMULTANEOUS ATTACK
2) BREATHY VOCAL ATTACK
3) GLOTTAL ATTACK
Vocal attacks are FUNCTIONAL not
pathological
However, when they are misused or used habitually, they may produce undesirable changes to the voice
Simultaneous Attack
reflects the proper coordination between respiration and phonation
The air is released as the folds meet at midline
This is the way voicing should be produced as it creates the LEAST STRESS on the folds
The most efficient way to produce voice
Breathy Vocal Attack
Significant air flow escapes through the vocal folds BEFORE they are adducted.
Breathiness can range from very mild to very pronounced or noticeable
A breathy vocal attack was a trademark for Marilyn Monroe
Glottal Attack
Adduction of the vocal folds occurs before air flow begins
Here, the folds are brought abruptly together to produce sound
Perceptually, this creates a harsh, tense sound that is created by “slamming” the folds together
It is also referred to as a HARD GLOTTAL ATTACK
Vibratory Cycle Characteristics (3 ways to view)
1) Changes in the glottal area
2) the mode of vocal fold vibration
3) the mechanics of vibration
During voicing, what happens to the glottal area?
It changes in size/shape
Values given here are for voicing at conversational pitch + intensity, during one cycle of vibration:
- Vocal Folds Open: 50%
- Closing Phase: 37%
- Vocal Folds Closed: 13%
These values change as you change pitch (frequency) or loudness (intensity)
Mode of vocal fold vibration
Refers to a way of doing something. Here, mode refers to how the vocal folds open and close
Mode of Vocal Fold Vibration - Abduction
The folds will open:
- length wise: posterior to anterior
- Medially: inferiorly to superiorly
Mode of vocal fold vibration - adduction
The folds will close:
- length wise: anterior to posterior
- medially, superiorly to inferiorly this correct or supposed to be opposite
Mechanics of Vocal Fold Vibration
The folds will vibrate mostly along their entire length
However, not everyone will adduct the folds completely during voicing
To raise pitch
increase vocal fold length + increase vocal fold tension by contraction of CRICOTHYROID and THYROVOCALIS
Pitch
the psychological correlate of frequency (vocal fold vibration measurement - hz/frequency)
Frequency, or pitch, is defined as the vibration of the vocal folds expressed as the number of cycles per second
As pitch increases, frequency increases
As pitch decreases, frequency also decreases
As pitch changes, appearance of the vocal folds also changes
To lower pitch
Decrease vocal fold length + decrease vocal fold tension, due to contraction of THYROMUSCULARIS
Pitch change is achieved by
changing the length, tension, and mass of the folds
These changes require muscular effort from cricothyroid and thyrovocalis
How are extrinsic laryngeal muscles used in pitch?
They can be used to produce extremely high (suprahyoid) or extremely low (infrahyoid) pitches. This is common, in a majority of cases, for professionally trained singers only
Cricothyroid and pitch
Cricothyroid will INCREASE pitch by STRETCHING the folds. It is the PRIMARY muscle used to regulate pitch ****
When cricothyroid contracts, the thyroid cartilage will tilt anteriorly
This action will:
increase tension
increase length
decrease the mass of the folds
= raised pitch
Thyromuscularis and pitch
Thyyromuscularis, a glottal relaxer, will LOWER pitch by RELAXING the folds if the arytenoids + thyroid cartilage are allowed to move TOWARD each other
Thyrovocalis
Tenser of folds
Role is minor
Makes fine-tuned adjustments in tension made by cricothyroid
Pitch Raising means
Increased tension
Increased length
decreased mass
Pitch lowering means
Decreased tension
Decreased length
Increased mass
Intensity
Loudness is a psychological correlate of intensity
Increased loudness is achieved by
1) Increasing subglottal pressure
2) Increasing medial compression of the folds
When medial compression increases, it takes more subglottal pressure to blow the folds apart
As intensity increases
1) The vocal folds are tightly adducted
2) The vocal folds return to an adducted position more quickly
3) The vocal folds remain adducted for a longer period of time
