1. Phonation

2. Functions of the larynx
3 valves which:-
Permit airflow in and out
Prevent inflow of unwanted substances
Expel through cough
Create subglottic pressure to brace thorax
Produce vocalisation
Reflexes control all above except phonation
Functions of the larynx (For subglottic pressure do hold chair and pull)
Larynx is basically a series of three valves that can open and close (or constrict and widen) to accomplish the following:
1. Permit air to enter and exit the trachea to maintain the life-sustaining activity of respiration.
2. Prevent anything other than air from entering the lower airways. This function is obviously important to maintain the patency of the airways for respiration. This function of the larynx is accomplished by the first of the three valves composed of the epiglottis and the aryepiglottic muscles. Which allow closure at the laryngeal aditus and with the superior and anterior movement of the larynx the bolus is encourages into the opened pharynx and not the now slightly higher laynx.
3. Expel through cough reflex foreign body that may enter the laryngeal cavities. The preventive action described above is not foolproof. Unwanted particles sometimes do find their way into the laryngeal cavities triggering the cough reflex. The two other valves – one formed by the ventricular folds and the other by the vocal folds – adduct abruptly during exhalation building up subglottal pressure (air pressure underneath the vocal folds). When both valves abruptly open, the forcful expelling of air that escapes carries it the foreign particles.
4. The development of subglottal pressure in order to brace and stabilize the thorax for lifting, excretion and childbirth. Both ventricular and vocal folds may be involved in this function of the larynx.
5. Produce tone for vocalization (crying, laughing, cooing and other non-speech sounds) speech and singing i.e. phonation. Typically, only the vocal valve is involved in the production of the laryngeal tone. However, ventricular folds are also capable of producing what is perceived as a harsh, strained sound.
Reflexes perform all functions except for speech and singing.

3. Valving for Speech
Phonation occurs through the use of the intrinsic laryngeal muscles and the laws of physics.
Glottis opened by posterior crico-arytenoid during unvoiced sounds
Glottis closed by lateral cricoarytenoid and inter-arytenoids
The rhythmic opening and closing of the glottis during phonation is accomplished through a set of intrinsic muscles of the larynx and by the laws of physics relating to flow of air. Intrinsic muscles are those that have both their attachments inside the larynx. Both membranous and cartilaginous portions of the vocal folds vibrate during phonation. The glottis is open (the vocal folds are held apart) during breathing and during the production of unvoiced sounds by the action of the paired posterior cricoarytenoid muscles.
To produce voice, the vocal folds are adducted primarily by the action of the lateral cricoarytenoid muscle. The paired muscles arise from the sides of the cricoid and attach to the muscular processes of the respective arytenoids. They rock and slide the arytenoids together. In addition, two other muscles aid adduction. The unpaired intra- or transverse arytenoid glides the arytenoids together and the paired oblique arytenoids pull the tip of the arytenoids together.

4. Valving for Speech

5. Glottic Cycle Vocal cords together Build up subglottic pressure
Vocal cords forced apart
Air rushes through gap
Reduced subglottic pressure
Vocal cords slap back together
Air from the neck of a balloon
Variation in compliance and complexity of wave
See it opens from back to front and closes from front to back
Also see opening starts from underneath

6. Glottic Cycle

7. Glottic Cycle
GO TO Movie
General anatomy/vocal folds/female and male

8. Aerodynamic Myoelastic Theory
Aerodynamic- air pressure and flow
Myoelastic- Elasticity of vocalis- the muscle in the vocal cord and the vocal ligament.

9. Bernoulli principle- Aerodynamics

10. Myoelastics -stiffness
Another muscular force is stiffness. If the vocal cords are stiff then they will give more resistance to the air. The effect is like the difference between punching a bag of water and a bag of molasses. There will be less movement in the molasses. Vocal cords may become stiffer through contraction, infection or swelling. Consider splat balls and normal rubber ball or Newton’s cradle
Another muscular force is stiffness. If the vocal cords are stiff then they will give more resistance to the air. The effect is like the difference between punching a bag of water and a bag of molasses. There will be less movement in the molasses. Vocal cords may become stiffer through contraction, infection or swelling. Consider splat balls and normal rubber ball or Newton’s cradle
 SEE MOVIE HIGH PITCH, General/pathology/hydration (pitch)

12. Periodicity A period is a complete and closing cycle.
Cycles/second = Frequency = Pitch
Regularity/Irregularity may occur in:
Pitch = Jitter
Amplitude = Shimmer (not singing shimmer
Vibrato may be called a fluctuation as it is regular
Middle C 256, C6 in scientific pitch notation (  Hz)
Not the same as a vocal Shimmer
Often increased jitter and shimmer at the ends of the pitch range
Hear as an interference to the clear note
Vibrato may be called a fluctuation as it is regular

13. Brainstorm
How is pitch controlled in instruments?

14. Pitch Control Theory is changing Three main variables Other factors
Mass- cross sectional bulk
Stiffness- longitudinal tension
Length
Other factors
Nervous tension
Lack auditory feedback
Each point at a time
Guess factors- although have handouts, also fatigue, illness, breathe support

15. Pitch Control Lydia’s assembly Movie Singing/use/norm commercial/rigid
Singing/use/classical/flex video standard and slow
OR Spg/use/normal actor

16. Cover, Transition Body Model Hirano
Cover is epithelium
Transition is the middle and deep layers of the lamina propria making the vocal ligament
Body of vocal cord is vocalis muscle
Body cover Model
In basic physics we know that the natural frequency of an oscillator is related to the stiffness to mass ratio. Stiffness of the vocal cord is largely regulated by vocal cord length. As the fibres are stretched fibres in the passive layer stiffen. Note also that a contracted muscle (shortened) muscle may be tighter than a stretched or elongated one.
As the cricothyroid CT contracts with the Thyroarytenoid TA inactive there is a lengthening of the vocal cord and the effective stiffness increases. This will cause a rise in Fundamental frequency F0.
 Where TA contracts and CT is inactive the length of the vocal cords will decrease and there will be a reduction in stiffness of the cover and an increase in stiffness of the body of the vocal cords. Usually the stiffness of the cover dominates the effect assist is closer proximity to the glottis where the vibrations are of the largest amplitude. F0 will probably decrease.
 Where CT and TA contract together so that the length is unchanged it is likely that F0 will increase slightly.
 CT is generally considered the main controller of pitch, The influence of TA must not be ruled out especially in the differential diagnosis of problems. There will be differences in normal voices in the extent to which each is activated. Also it may be that as one is trained more the other is relatively inactivated. This is possible because 2 separate branches of the vagus nerve innervate the muscles.

17. Body and Cover Model
TA by RLN CT by SLN
 Stiffness may be altered by a number of biological factors such as foods, drugs, hormones, disease, infection or dehydration.
 Titze p198 The CT works by contracting its 2 muscles, the pars recta which pulls the front of the thyroid cartilage down and the pars oblique which pulls it slightly forward. The extent of the action will also be dependent on the stability of the arytenoids.
 Analogies to strings and rubber bands. Because of the non-compliance of a steel string a small change to the peg on a guitar for example gives rise to a big change in pitch. The vocal cords on the other hand need a bigger pull to make a change. If you try this with an elastic band you may find when you stretch it only a little the pitch may go down because the stretch does not overcome the length increase.
The stress in the cover of the vocal cord can also, in principle be increased, by the thinning of the effective cross section of closure. i.e. the contact area becomes thinned. This may occur in the changing to a lighter register such as falsetto. The change in thickness overcomes the increase in length, which also goes with this register.
The movement of the cover is the mucosal wave, which is imperative to good vocal quality. A lesion, external irritation such as mucus of dryness or tethering from surgery will affect quality.

18. New models Epithelium Basement membrane Metabolically active
Microvilli
Catching mucous
Basement membrane
Boundary between epithelium and lamina propria
Anchoring fibres (allow some gliding) and proteins such as hyaluronic acid

19. Properties of the vocal cords
Stiffness mainly regulated by length
Stretch and contracted muscle is also stiffer
Vocal cords quite stretchy
Wet slap due to compliance

20. Optimum Pitch The pitch created by the larynx in its neutral position
Debate
Larynx not move vertically to create this pitch
Methods to achieve –
Mmhmm
Neutral counting
i.e. the pitch at which any individual voice should be ideally placed. Not how some people have changes their pitch e.g. Mrs Thatcher, Tony Blair, David Beckham
This has long been a topic for discussion – as to whether this really exists. When making a judgement about pitch loudness and timbre also affect the subjective judgement. If the pitch is appropriate then it draws little attention but if not it can reduce acceptability and intelligibility of the human voice. David Beckham, puberphonia
It makes sense that a non-stressful pitch will be one not at the extreme of the vocal range. Somewhere in the bottom 1/3 or ½ of Fo is likely to be the best. (Titze 1994) Consider also the voice immediately after getting out of bed compared with the voice midday or the voice after singing loudly to the radio or vocal exercise. Coleman and Markham 1991 in Titze measured this change. So perhaps the optimum pitch for each voice is not an absolute
NB Pitch will decrease with a cold or if VC swollen. Will return when swelling reduced
Movie Speaking/care/habitual pitch

21. Control of Vocal Intensity
Increase in volume occurs with:
Increased subglottic pressure
Medial compression of the vocal cords
Resistance to increased pressure by:
Medial compression
Tightness of abduction
NB Trained singers may use less lung pressure to produce high volume
Voices get louder with 1) increased subglottic pressure and 2) medial compression of the vocal folds. Consider the continuum of breathy voice to normal voice and from normal voice to pressed or harsh voice. Intensity increases reaches a peak and decreases again. Thus there appears to be a glottal setting when the intensity is maximised.
In therapy it is often the case that the need is to re-establish the balance.
Conversational speech has a sound pressure level (SPL) of about decibels (dB) and shouting about 95 – 100dB when measures at 1 metre from the mouth.
There is a direct relationship between subglottic pressure and the intensity of the voice.
Resistance to increasing SPL is brought about mainly by medial compression and the tightness of adduction. Tight adduction is mainly due to the action of the transverse and oblique arytenoids.
It seems that trained singers may use less lung pressure/effort to produce higher volumes than in untrained singers. (Titze and Sundberg 1992
Much of our control of volume is subconscious. An example is the Lombard effect, which is the adjustment of loudness according to the level of auditory stimulation. E.g. when someone speaks while listening to music on headphones talking louder than needed.

22. Control of Vocal Intensity
Show Movie Speaking/abuse/distance point out not good technique

23. Phonation onsets Glottal- closure before sound
Breathy- air before sound
Simultaneous.

24. Phonation types Thick vocal folds, Thin vocal folds Stiff vocal folds
Speaking voice, Chest register
Thin vocal folds
Quiet voice, Head register
Stiff vocal folds
Falsetto
Floppy vocal cords
Creak - irregular vibration
Thin cords for speaking no projection
Creak thick and floppy no projection if tense becomes rough and strained