The Phonatory System

The Phonatory System

Cricoarytenoid Joint

Joints of the Larynx

• Formed by the articulation between the base of each arytenoid and the superior surface of the quadrate lamina of the cricoid
• Joints are diarthodial
• Allows a wide range of motion of the arytenoids, which can glide medially, laterally as well as rock back and forth in a rocking motion

There are 2 pairs of joints in the larynx which play important roles in the production of normal voice

• Cricoarytenoid joint
• Cricothyroid joint

Cricothyroid Joint

There are several cartilages that do not play an important role in voice production

Corniculate Cartilages

• apex of arytenoids
• not present in all individuals

Cuneiform Cartilages

• small elastic rods of cartilage embedded within the aryepiglottic folds
• primary function to stiffen those folds

In about 30 percent of people with rheumatoid arthritis, there is inflammation of a joint near the windpipe called the cricoarytenoid joint. Inflammation of this joint can cause hoarseness and difficulty breathing.

*Symptoms include the following:

• Hoarseness
• Pain when swallowing
• Sensation of having something stuck in your throat
• Pain when talking or coughing
• Shortness of breath

- May be treated with a high dose of corticosteroids

• Located between each inferior horn of the thyroid and the sides of the cricoid cartilage.
• Allows the thyroid cartilage to tilt downward and upward.
• Increases the distance between the arytenoid cartilages.
• Increasing the distance effects the vocal folds.
• Makes them more tense and thin

-when stretched they vibrate more rapidly resulting in a higher pitch.

• The arytenoids are crucial for phonation because the vocal folds are attached to the vocal processes.
• Various other muscles of the larynx are attached to the muscular process also and move the arytenoids which allows the vocal folds to be positioned in different ways.
• Involved in lengthening and tensing of the folds

Arytenoid Cartilage

• The Cricothyroid joints are the main agent in the fundamental frequency (pitch) regulation of the human voice.

• Acts as a pivot between the thyroid and cricoid cartilages.

• Paired Cartilage
• Small structure on the superior surface of the cricoid
• Pyramid shaped

• 2 projections extended from their base
• Vocal Process
• Muscular Process

Valves within the Larynx

The Larynx

The Epiglottis is very important during swallowing! It folds downward over the entrance to the larynx. Acts as a bridge to direct food and liquids to the esophagus. Involuntary act, prevents aspiration.

Epiglottis

Inside the Larynx

• Broad cartilage shaped like an oak leaf
• Attach to the inner surface of the thyroid cartilage just below the thyroid surface notch

Lumen:

• A hollow tube directly inside the larynx, which has 3 valves within it.
• The valves open and close, each having their own specific tasks to perform.
• 3 Valves:
• Aryepiglottic Folds
• False Vocal Folds
• True Vocal Folds

The larynx is an organ in the neck involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume. The larynx houses the vocal folds which are essential for phonation.

1) Aryepiglottic Folds

Cricoid Cartilage

• Placement: Most superior of the folds
• Location: Along the sides of the epiglottis to apex of both arytenoid cartilage.
• Made up of: sheets of connective tissue and some muscle fiber.
• Function: to contract in a circular action in order to pull the epiglottis backward which closes the entrance of the larynx when swallowing.
• Prevents aspiration

• Named because of its shape. Latin for Signet Ring
• Narrow in the front and larger in the back
• Complete ring of cartilage, just above the first ring of the trachea

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2) False Vocal Folds

• Placement: inferior to aryepiglottic, superior & parallel to True Vocal Folds
• Made up of : Not very muscular structure—capable of limited movement
• Function:
• Open: during phonation
• Closed: during swallowing, effortful activities, and pathological conditions.
• (i.e.: lift heavy objects, child-birth )
• Laryngeal ventricle: separates False/True vocal folds.

Superior Horns

• 2 long projections at either side of the thyroid
• Extends upward and connected by ligaments to the thyroid

Inferior Horns

• 2 shorter projections
• Extends downward and articulate with the sides the cricoid cartilage

3) True Vocal Folds

Thyroid Cartilage

• Most complex of laryngeal valves.
• Consist of 5 layers:
• Thyroarytenoid muscles
• (3) layers of mucous membrane
• Surrounding the muscle
• Layer of epithelium
• Covering the mucous membrane

• The largest of the Larynx
• 2 plates of cartilage are fused in the front
• Occurs at an angle forming the Adam's Apple
• Thyroid notch is at the top surface of the laryngeal protrusion
• The posterior portion of the thyroid is open
• The vocal folds attach to the inner surface of the thyroid

True Vocal Folds

Hyoid Bone

• Epithelium: the outermost layer of the vocal folds
• Thin and flexible
• Tough layer of tissue
• Lamina Propria: is mucous membrane, deep to epithelium and the basement membrane.
• Composed of 3 layers
• Thyroarytenoid muscle:
• Main mass of the vocal folds
• Considerably thicker, denser, and stiffer than other layers.

Lamina Propria

The cartilaginous framework of the larynx is suspended from the hyoid bone.

• It is the attachment for the tongue
• The larynx is suspended from it by the hypothyroid membrane
• Consists of the body in the front and the major horns which form the U. The minor horn protudes slightly form each horn.

Laryngeal Skeleton

The laryngeal skeleton is made up of 1 bone and 9 cartilages

• Reinke’s Space/ (superficial layer)
• Most elastic fibers
• Higher degree of compliance
• Intermediate layer of Lamina Propria:
• Elastic fibers
• More densely packed
• Less compliant
• Deep Layer:
• Made of collagen fibers
• Stiffer than the other layers

Cover-Body Model

Glottis

Laryngeal Framework:

• Unpaired Cartilages
• Thyroid
• Cricoid
• Epiglottis
• Paired Cartilages
• Arytenoids
• Corniculates
• Cuneiforms

Infrahyoid Muscles Cont.

• Classifies 5 structural layers into 3 biomechanical layers.
• Based on degree of stiffness of each layer
• The Cover: consists of the epithelium and the superficial layer of the lamina propria.
• The Transitions (vocal ligament)
• Encompasses intermediate and deep layers of lamina propria
• Less compliant than cover.
• Thyroarytenoid muscle: forms the body of vocal folds
• Least compliant layer of vocal folds

• Structural and biomechanical complexity causes intricate periodic sounds waves that allows rich and resonant voice.

1- Cartilages

2- membranes and ligaments

3- Joints of the larynx

Infrahyoid Muscles

• Is the space between the true vocal folds.
• They’re divided into membranous glottis and cartilaginous glottis.
• Cartilaginous Glottis: the vocal processes form the lateral edges.
• Accounts for posterior two-fifths of the glottis
• 4-8mm: depending on sex, age, and build
• Membranous Glottis: forms anterior three fifths of the entire length of the glottis in adults.
• Bound by vocal ligaments
• Adult males: 15mm
• Adult females: 12mm

• Omohyoid
• Attachment: Scapula to inferior border of hyoid
• Function: Depresses and retracts hyoid bone
• Thyrohyoid
• Attachment: Oblique line of thyroid lamina to major horn of hyoid
• Function: Draws hyoid and thyroid closer to each other

Suprahyoid Muscles

• Sternohyoid
• Attachment: Clavicle and sternum to body of hyoid
• Function: Depresses hyoid bone and larynx
• Sternothyroid
• Attachment: First costal cartilage and sternum to oblique line of thyroid lamina
• Function: Depresses hyoid bone and larynx

Shape of the Glottis

• Depends on position of vocal folds.
• Examples:
• Quiet breathing: glottis open, vocal folds in paramedian position.
• Breathing: glottis open more widely, vocal folds in forced abduction.
• Phonation: glottis is closed, vocal folds in median position.
• Whispering: membranous glottis closed with cartilaginous glottis open.

• Digastric
• Attachment: Posterior belly: mastoid process of temporal bone to hyoid bone, Anterior belly: mandible to intermediate tendon of digastric muscle
• Function: Elevate hyoid bone
• Stylohyoid
• Attachment: Styloid process of temporal bone to body of hyoid bone
• Function: Elevates and retracts hyoid

Extrinsic Muscles

• Infrahyoids
• Have a point of attachment at the structures below the hyoid bone, including the sternum and scapula
• Suprahyoids
• Have a point of attachment at the structures above the hyoid bone, including the mandible and temporal bone

Suprahyoid Muscles Cont.

Mylohyoid

• Attachment: Body of mandible to hyoid
• Function: Elevates hyoid bone

Geniohyoid

• Attachment: Mental symphysis of mandible to body of hyoid bone
• Function: Pull hyoid bone anteriorly and superiorly

Muscles of the Larynx

Now time for Phonatory System Bingo!

Intrinsic Muscles

• Cricothyroid

Pars Recta

• Attachment: Anterior cricoid to inferior border of thyroid
• Function: Elongate and tense vocal folds

Pars Oblique

• Attachment: Anterior cricoid to anterior surface of inferior horn of thyroid
• Function: Elongates and tense vocal folds

Divided into two groups:

• Extrinsic (Also known as the strap muscles)
• Have one point of attachment to the larynx, either at the hyoid bone or another laryngeal cartilage, and another point of attachment outside of the larynx
• Intrinsic
• Both points of attachment are within the larynx

Intrinsic Muscles Cont.

Posterior Cricoaryntenoid

• Attachment: Posterior cricoid to muscular process of arytenoid
• Function: Abduct vocal folds

Thyroarytenoid

• Muscularis
• Attachment: Anterior commissure to muscular process
• Function: Body of vocal folds; shorten and relax folds
• Vocalis
• Attachment: Anterior commissure to vocal process
• Function: Body of vocal folds; tense folds

Intrinsic Muscles Cont.

Lateral Cricoaryntenoid

• Attachments: Lateral cricoid to muscular process of arytenoid
• Function: Adduct vocal folds

Interarytenoid

• Transverse
• Attachments: Lateral margin of one arytenoid to lateral margin of other arytenoid posteriorly
• Function: Adduct vocal folds
• Oblique
• Attachments: Base of one arytenoid to apex of other arytenoid posteriorly
• Function: Adduct vocal folds

Voice Amplitude/Intensity

Average Amplitude Level

Maximum Potential Frequency Range

Mucosal Wave

Phases of a Cycle of Vibration

• MPFR- Complete range of frequencies we can generate. Different from Fₒ variability because it reflects the range of Fₒ a person uses in connected speech.
• MPFR ranges from the lowest tone a person can sustain to the highest (including falsetto).
• Lowest frequency adult males can produce is 80 Hz and highest is around 700 Hz. Adult females can produce as low as 135 Hz and high can be over 1000 Hz. (Insert video)
• MPFR is useful because it reflects physiological limits of a speaker’s voice and physical condition of vocal mechanism.

• Amplitude and intensity are interchangeable terms when it comes to vocal loudness.
• Average amplitude refers to overall level of amplitude during speech tasks.

• Wave-like motion that is evident on the vocal folds, caused by timing differences.
• The vocal folds open from bottom to top and close from bottom to top.
• As the superior margins begin to approximate, the inferior edges are already beginning to separate due to an increase of subglottal pressure- VERTICAL PHASE DIFFERENCE

• DUTY CYCLE- opening, open, closing, closed
• One cycle of vocal fold vibration constitutes as one opening and closing of the glottis

Phonatory System

The Process of VF Vibration

Amplitude Variability

Frequency Variability

• The vocal folds begin to recoil back to the midline due to their natural elasticity.
• As the vocal folds begin to close, they form a narrow channel and the air pressure becomes negative (Pneg) which additionally helps to adduct the vocal folds.
• BERNOULLI’S PRINCIPLE- A gas such as air, passing through a narrow channel, increases in velocity and decreases in pressure.

• Amplitude will vary depending on the speaker’s mood, the conveyed message, stress/accenting, and social context.
• Amplitude variability is an important indicator of emphasis and emotion, so inability to vary in loudness can seriously impact someone’s communication effectiveness.

Mucosal Wave

• Fₒ levels change constantly due to intonation, different accenting and stress on syllables, and grammar.
• More extensive Fₒ changes occur if the speaker is excited.
• Fₒ changes correspond to frequency variability.
• Too much/too little variability can indicate a functional, organic, or neurogenic voice problem.

The Process of VF Vibration

Dynamic Range

• The vocal folds open from their posterior attachment at the vocal processes to the anterior portion of the anterior commissure.
• HOWEVER, they close in an anterior to posterior direction.
• This is called LONGITUDINAL PHASE DIFFERENCE

• The subglottal pressure (PS) increases and eventually forces the vocal folds apart.
• As the glottis opens due to the positive pressure, the mass of air flowing through it meets the air above it, creating COMPRESSION and increased positive pressure.
• As the air continues to travel through the SLVT, the distance between the glottis and body of air increases, resulting in a NEGATIVE SUPRAGLOTTAL air pressure

• Dynamic range is similar to MPFR in that it relates to physiological range of vocal amplitude.
• Amplitudes above and below 60-80 dB range are not usually used for conversational speech. However, ability to raise/lower voice for certain situations is important based on social context.

Voice Production

Frquency & Intensity Variables

Average Fundamental Frequency

Phonation Threshold Pressure

• Self-sustaining oscillator
• The vocal folds act as a sound generator by vibrating the air coming through the larynx from the lungs, and setting up a sound wave in the vocal tract.
• The lateral cricoarytenoid (LCA) & interarytenoid (IA) muscles ADDUCT the glottis and exert a force called MEDIAL COMPRESSION.

Acoustic Measures of Phonatory Variables

• Minimum amount of subglottal pressure needed to set the vocal folds into vibration
• REVIEW- The Ps has to be higher than that above so that air will flow through the glottis.
• For normal conversation, PTP ranges from about 3cm H2O at a low F0 to around 6cm H2O at a higher F0 .
• Higher pressures are needed for louder speech- around 50 cm H2O.

• Fₒ is the rate at which vocal folds vibrate.
• Fₒ depends on the vocal fold length, tissue, density, and tension. The greater the length, density, and tension, the slower the vibration.
• Vocal Fₒ is determined by the tension of the vocal fold cover, not by the actual length of the vocal folds.

Myoelastic Aerodynamic Theory of Phonation

VRP

• Comprises the larynx
• Laryngeal function is controlled and regulated by the nervous system.
• Air is converted into sound through an incredibly complex process
• Involves air pressures and flows generated by the respiratory system and muscular and elastic properties of the vocal folds.

Glottal Spectrum

Noise Measurements

• Spectrum of the human voice; does not represent the sound of a voice one hears; examined before its resonated and articulated
• Corresponds to the source function of the source-filter theory
• Shows that the F0 is the lowest frequency and has the highest amplitude

• Graph that plots a person’s maximum phonational range against his or her dynamic range.
• Dynamic range is vertical axis measured in dB SPL.
• Fₒ is the horizontal axis measured in Hz.

• NHR can be converted to HNR data with this formula reported by Smits, Ceuppens, and DeBodt (2005):
• HNR = 20 X log (1/NHR)
• Average HNR values for normally speaking adults/children- Table 5.10 on page 188

“The vibration of the vocal folds generates a nearly periodic, complex sound wave with a fundamental frequency (Fₒ) and harmonics.” (pg. 179)

Glottal Spectrum

VRP

• As the harmonic frequencies increase, their amplitudes decrease at a rate of 12dB per octave. ie) -12dB between 100 and 200 Hz, -12dB from 200-400 Hz…
• Because of this decrease of acoustic energy as frequency increases, there is more acoustic energy in lower frequencies of the voice and less in higher frequencies.
• Acoustic energy of the human voice has been shown to significant up to ~4000-5000 Hz.

Noise Measurements

Cause of Cycle Vibrations

Harmonic Spacing

• Variations in lung pressure can also cause perturbations in vocal fold amplitude and frequency, because Ps fluctuates during the build up and release of the pressure thru the glottis.
• The articulators influence VF vibration
• When the tongue moves forward, it pulls the hyoid bone forward and upward, which raises the larynx. This causes a change in stiffness of the VF, thereby perturbating the F0.

• Provides ratio of the proportion of harmonic sounds (periodic) to noise sounds (aperiodic).
• Noise measures: Harmonics-to-noise ratio (HNR), Noise-to-harmonics ratio (NHR), and normalized noise energy (NNE).
• HNR and NHR are most common.
• Higher HNR values = more harmonic components over noise.
• Higher NHR values = more noise over harmonic components.

Perturbation Measures

• Refers to the distance between the harmonic frequencies in a complex sound
• Harmonics are whole number multiples of F0, so they change with each change in frequency.
• The higher a person’s F0, the wider the harmonic spacing is, causing a thin voice without a rich, resonant quality
• Prepubertal children have a fundamental frequency of 300 Hz. Women- 200 Hz. Men- 100 Hz

Cause of Cycle Vibrations

Nearly Periodic Nature of the Human Voice

Perturbation Measures

• Frequency and amplitude perturbation (jitter and shimmer)- measured in terms of cycle-to-cycle differences in period and amplitude of each cycle of vocal fold vibration.
• Computer program allows measurement of jitter and shimmer:
• Multidimensional Voice Program (MDVP) by Kay Pentax
• TF32 (suprersedes CSpeech)
• Dr. Speech (Tiger Electronics)
• Praat

• The vocal folds do not vibrate in a completely even, periodic manner; there are always FLUCTUATIONS IN AMPLITUDE and FREQUENCY.
• Timing variability between cycles of vibration is called FREQUENCY PERTURBATION, or jitter.
• Similarly, the loudness level fluctuates; this is called AMPLITUDE PERTURBATION, or shimmer.

• Caused from neurologic, biomechanic, and aerodynamic factors.
• The larynx is susceptible to small fluctuations in neural, vascular, respiratory, and lymphatic transport systems, detected by vibratory patterns of the vocal folds.
• The vocal folds may not be symmetrical and may differ in tissue density and tension. One may have more mucous on it, causing a slightly increased density.
• Aerodynamic events can cause changes in VF cycles of vibration
• The air forced thru the glottis can become unstable and turbulent, resulting in rapid pressure fluctuations in the vocal output.

Perturbation Measures

• Too little jitter and shimmer in voice result in perception of unnaturalness.
• 1% or less jitter is normal in human voice. Jitter values above normal indicate vocal fold vibration is not as periodic as it should be, and something is probably interfering with the vocal folds.
• Shimmer has not been explored as extensively, but it is known that shimmer values should be < 0.5 dB. (That’s considered normal.)

Registers

Speech Production

Defining Vocal Quality

Defining Vocal Quality

Vocal quality is...

• Is used in both singing and speech production contexts to denote specific portions of the total F range.
• Singing Context: usually refers to vocal’s range, resonance area (head voice, chest voice), vocal quality, and region of vocal break.
• Chest register: indicates a midrange of pitches
• Falsetto: higher range of pitches
• Head register: mix between chest and falsetto

• For example, a phonetician may use vocal quality to distinguish phonemes…
• While a singer may refer to vocal quality using different registers
• Quality can be described by different voice types such as breathy, hoarse, and harsh

What is vocal quality?

• There is no official or accepted definition for vocal quality
• This is because the concept of vocal quality has been used in different context by different professionals

A multidimensional entity linked to many aspects of voice production such as

• Voice production
• Amplitude
• Resonance Characteristics
• Rate of speech

Middle C

The quality of a person's voice is...

The LARNGEAL TONE has:

• a fundamental frequency
• and harmonics

The F0 corresponds to the perceived pitch of voice

• Defined in relation to voice physiology, acoustic, and aerodynamic parameters of voice production and perceptual vocal characteristics

• Voice production, divided into 3 registers
• Pulse register
• Modal register
• Falsetto register

• Middle C on the piano and the violin have the same F0
• We can easily distinguish that two different instruments are being played because each has a unique tone
• This relates to the acoustic quality of the instrument and the spectrum of the resulting sound

Determined by

• How well the vocal folds vibrate
• The shape and configuration of the vocal tract

• Including length, degree of arching of hard palate, and size of the oral cavity in relation to the size of pharynx

Why are voices distingushiable?

Voices sound different

• Even when pitch is perceived as the same
• Because the harmonic content differs

• For example: Imagine someone playing the note middle C on a piano. Then they play middle C on a Violin.

We can distinguish male and female voices because:

• Females have a slightly different vocal tract configuration than men
• When males and females produce a sound with the same F0…
• It is still easy to distinguish a male voice from a female voice by its quality

The way vocal folds vibrate plays an important role in shaping voice quality

Hoarseness

• When the vocal folds adduct too tightly with too much medial compression they become hyperadducted
• Muscular tension is upset when the vocal fold are hyperaddcuted
• The resulting voice is perceived as TENSE and PRESSED

• Determined by the amount of spectral noise resulting from the flow of turbulent air through the glottis
• Related to how periodically the VFs are vibrating
• When VFs are irritated/swollen they vibrated in a less periodic fashion
• Inflammation interferes with the mucosal wave causing lower frequencies between 100 and 2600 Hz

Hyperadducted Vocal Folds

Registers

Can be caused by:

• Vocally damaging behaviors
• Neurological diseases

Rough/Hoarse Voice

• Roughness refers to raspy sound in the voice with a perception of low pitch
• Hoarseness refers to a combination of breathy and rough qualities of the voice
• Common symptom for laryngeal disorders
• Laryngitis to life threatening cancerous tumors

• Pulse: Refers to a range of very low F0
• Described as a creaky, popping sort of sound
• Also referred as: vocal fry , glottal fry, or creaky voice

• Modal: Most commonly use
• normal conversation

• Falsetto: Refers to very high range of F0
• Also referred to loft register

Use of Registers:

Examples of Vocal Abuse

Breathy voice is a symptom for:

• Abusive laughter/singing
• Alcohol intake
• Coughing
• Inadequate breath support
• Smoking cigarettes
• Excessive throat clearing
• Inappropriately high pitch

• Singing:
• Is important to make transitions as smooth as possible.
• Important in certain genres:
• i.e.: yodeling/country/ folk/gospel
• Speaking:
• Model register is most common in speech
• USE: necessary for linguistic, esthetic, or physiological reasons.
• Used at end of phrases and sentences
• Common switch to pulse
• If falsetto or pulse is used as primary register it is classified as a voice problem which

• Organic and functional voice disorders (vocal fold paralysis)
• Increased breathiness is also associated with aging
• However, breathy voice is not always abnormal

Vocal

Quality

Vocal Fold Vibration

Vocal Registers

Breathy Voice Cont.

• When the VFs do not adduct tightly they are hypoadducted
• Balance between muscular and aerodynamic forces is upset, causing:
• Not enough muscle force
• The VFs do not provide proper resistance to the flow of air
• Air escapes between the VFs without being converted into acoustic energy

• Voice signal has more high-frequency energy that a non breathy signal
• Breathiness is an inefficient form of phonation
• The dynamic range is limited because less subglottal pressure builds up
• A person with a breathy voice uses 3-4x the normal amount of air per second during phonation

Hypoadducted Vocal Folds

Distinguishing Registers:

• This loss of air creates turbulence
• The turbulence passes through the VFs
• And adds a noisy, breathy quality to the vocal tone

Breathy Voice

• When the VFs do not adduct completely
• Results in a continuous flow of air during entire vibratory cycle
• Vocal tone that sounds aspirated with audible air escape during phonation
• VFs are close enough to be vibrated but the sound of air being continuously released accompanies the sound wave
• Turbulent airflow pattern results I na less periodic acoustic signal

Physiological and Acoustic Characteristics: Falsetto

Hypoadduction is caused by...

• Each is produced by a different manner of vocal fold vibration
• Particular patterns of vibration is usually confined to certain F0 range.
• They are distinct regions of vocal quality that can be maintained over some ranges of F0 and intensity

• Inappropriate vocal usage
• Neurological problems such as
• vocal fold paralysis

Abnormal Vocal Quality

• A generic term for any voice that sounds deviant in terms of quality, pitch, or loudness is DYSPHONIA
• Most accepted terms to describe different voice qualities are breathiness, roughness, and hoarseness

Velopharyngeal Valving

• To Produce:
• Cricothyroid muscle: exerts a great deal of longitudinal tension.
• Vocal Folds: appear very long, stiff, thin and sharp along the edges
• Cover of folds are lax
• Never quite closing
• Slightly breathy component
• Glottis: tight and narrow
• Vocal ligament: tensed
• High vibration: flutelike tone

• Contributes to voice quality
• Inadequate velopharyngeal closure results in…
• Hypernasality: excessive nasal resonance

6 Parameters of normal vocal quality

• Maximum frequency range
• Speaking F0
• Maximum phonation time
• Minimum-maximum intensity at various F0 levels
• Periodicity of vibration
• Noise generated by turbulent airflow

• Conditions that prevent the flow or air through the nasal cavities result in:
• Insufficient nasal resonance on nasal sounds
• This creates HYPONASALITY

Sound Shift

Objective description of voice

Subjective

Terminology

• Subjective terms are used to describe voice disorders
• pleasant, strident, rough, raspy, shrill, clear, unpleasant, harsh, hoarse, tinny, and strained
• The abundance of terminology is a problem in clinical management of voice disorders.

Researchers and clinicians have tried to specify the acoustic and physiological bases that form the foundation of NORMAL VOICE

Normal voice is defined when:

Defining Normal Vocal Quality

Physiological and Acoustic Characteristics: Pulse

• What one individual perceives as rough may be perceived by another as hoarse or strident
• Professionals using these terms have no standard frame for voice quality
• Subjective terms do not indicate underlying patterns of vocal fold vibrations that are contributing to the resulting quality

• Occurs in conversation when voice reaches it upper limits
• Manner of vocal fold vibration changes
• I.e. : Modal->Pulse, Modal ->Falsetto
• Change in vibration= change in voice quality
• Is abrupt; noticeable to speaker and listener

• Quality is clear
• Pitch and loudness are appropriate for age, sex, and situation
• Voice is produced without effort, pain, fatigue, or strain
• Voice is satisfactory to speaker in terms of fulfilling his or her occupational, social, and emotional vocal needs

• It is important to note that normal voices differ on depending factors such as:
• sex, age, build, culture, region, personality, degree of voice use, and health of the speaker

Physiological and Acoustic Characteristics: Modal

• To Produce:
• Vocal folds: are short and thick
• Come into contact with True vocal folds
• Increase vibrating mass
• Decrease fundamental frequency
• Medial edges of folds are loosely adducted
• Glottis:
• Multiphasic closure: separates 3 times before completely adducting.
• Temporal Gap: no acoustic energy present
• Energy dies out.
• Human ear picks the gap up which creates the creaky/popping noise.

• Full participation of the cover and body during vibration.
• Generates greatest range of amplitudes in register
• Vocal folds somewhat shorter in length—compared to non-vibrating.
• Cover—slack
• Body—fully involved

• Duty Cycle:
• Rapid onset
• Brief open phase
• Longer closing phase
• Short closed phase

A comparison of vocal demands with vocal performance among classroom student teachers

What are the effects of teaching vocal demands on your voice?

Franca, Maria. A comparison of vocal demands with vocal performance among classroom student teachers. Journal of Communication Disorders, 46, 111-123. Retrieved from ScienceDirect.