Phonation Flashcards
What is Phonation?
the act of making sound.
Vocal Fold Length?
Females - 12.5mm - 17.5mm (1/2 - 3/4 inch)
Males - 17mm - 25mm (3/4 - 1 inch)
Bernouli Effect
Increased motion of gas molecules = decrease pressure.
Elastic Recoil
the ability of a stretched object or organ to return to its resting position or equilibrium.
Equilibrium
state of balance
3 types of Equilibrium
- stable
- unstable
- neutral
Self sustained vocal fold vibration
- no Bernouli effect required.
1. vocal folds have a stable equilibrium when adducted.
2. airflow generated by lung pressure, moves vocal folds apart (away from equilibrium).
3. Elastic recoil kicks in (vocal folds want to return to Equilibrium)
4. momentum carries vocal folds past their Equilibrium.
5. Vocal Folds want to, once again, return to Equilibrium (from the other direction).
6. Airflow, generated by Lung Pressure, moves Vocal Folds apart (away from Equilibrium).
What is Subglottic Pressure?
pressure built up under the vocal folds
Other info about Subglottic Pressure
Roughly equivalent to alveoli or thoracic pressure, but it involves a resistance at the vocal folds. The glottis is the space between the vocal folds.
Pressure is measured in cm H20
Subglottic Pressure used in varying dynamics
- Very soft phonation - 3cm H20 (water)
- Normal speech 4-9 cm H20 (should not vary more than +/- 1 cm H20 during a breath group)
- Loud sounds - 20cm and 70cm H20 (depends on voice type, thickness of vocal folds etc.)
- Heavy Lifting - 150cm H20
Indications there is an improper amount of Sub-glottic Pressure
- Decreased flexibility/Stability
- Voice Cracking/Excessive noise in the sound
- Breathy sound/lack of clarity in the sound
- Outward signs of strain (should’t be rewarded as your working hard).
- Pitch is either sharp or flat.
- Vibrato irregular (too fast, too slow, uneven)
Titze on the difference between Trained & Untrained Singers
Titze (1992) - the primary difference between trained and untrained singers is that singers obtain 2 to 3 times greater peak flow for a given lung pressure, suggesting that they adjust their glottal or vocal tract impedance for optimal flow transfer between the source and the resonators.
4 Factors that determine the fundamental frequency (F0) and intensity of the sound:
- Vocal Fold tension or Glottal resistance
- Aerodynamic Power (ratio of Psub to air flow)
- Length of the Vocal Folds
- Mass of the Vocal Folds.
Low Frequencies
Pitch/intensities regulated by Glottal Resistance (degree and closure time)
Higher Frequencies
ALL ABOUT AIR FLOW
Flow Rate….
Flow rate almost doubles for increase of 10 dB
What is flow phonation?
Highest possible Air Flow with Complete Glottal Closure.
Generous Airflow…..
Generous airflow is advantageous is for vocal fold function.
Titze Agrees -
Below the Larynx - Aerodynamic Power derived from Psub and Airflow
Within the Larynx - Aerodynamic Power converted to Acoustic Power
Controlled by Prephonatory Glottal Width
*Slight Spreading of Vocal Processes during Flow Phonation is a sign of increase GW.
Increase in dB
Boost of 3 dB for one-millimeter increase in glottal width due to increased Air Flow
Possible to achieve up to 4-7 dB increase with GW increase as opposed to 8-9 dB with doubling Psub
Breathiness in Singing
Breathiness is commonly caused by poor breathing and or inefficient resonation. Regardless of the aesthetic questions involved, an aspirate attack is not vocally destructive, merely an inefficient kind of voice production.
Psub and out of tune singing
…singers consistently sing out of tune if they fail to use the proper subglottic pressure.
The only real consensus is…..
The only real consensus is that a combination of abdominal (or diaphragmatic) and thoracic breathing encourages the best cooperation between the air stream and the vibrating vocal folds.
Emphasize…..
Emphasize Breath Flow in your teaching!!!!
