Vocal Fold Vibration Flashcards
Vertical Phase Difference
inferior margins of the vocal folds open first and close first.
superior margins open last and close last
Longitudinal Wave
posterior portion of vocal folds open first and close last
anterior portion opens last and close first
The goal of VF waves is to
SHAPE the air pressure released by the glottis
Describe the 1-Mass Model of VF Vibration
the mass of one VF is represented by a rectangular block.
the spring signifies the recoil force of the VFs
this model fails to fully explain VF vibration because there is a lot MORE movement
Describe the 3-Mass Model of VF Vibration
made to overcome the limitations of the 1 mass model.
M=body mass=lateral movements
M1 and M2=cover masses=vertical phase differences
Different degrees of adduction result in….
perceptual voice features such as normal, breathy, and pressed vocal quality.
What causes a breathy voice?
the folds start vibrating before closure is achieved, full closure is not reached
What causes a pressed voice?
very high medial compression forces
What is fundamental frequency?
the rate of vibration of the VFs (Fo)
corresponds to perceptual pitch
What is the sound source for speech?
laryngeal vibration
How long does a single cycle of opening and closing of the VF take?
~1/100th of a second
How many times a second does this cycle repeat itself?
100-250 times/sec
depends on male/female
What creates the sound we hear?
“puffs of air” that are released during each cycle NOT the impact of the folds coming together
What is the glottal spectrum?
the numerous energies that are produced by the vibrating vocal folds….for example harmonics
How many harmonics are present in the human voice?
~40
If the Fo of an individual’s VFs is 100 Hz, then what energies do the harmonics of the sound-wave created?
100x2=200
100x3=300
As Fo increases….what happens to harmonics?
harmonics spread out
Fo=200 200x2=400 200x3=600 200x4=800 ....
What can enhance or suppress harmonics?
the shape of the vocal tract (acts as a filter)
VF do not vibrate in a completely even manner due to..
variations in tissu structure, variations in lung pressures, VF length and symmetry differences
What is jitter?
the timing variability between cycles of vibration.
frequencies
Which populations have higher jitter values?
children and elderly
What is shimmer?
differences in amplitude from one cycle to the next
loudness
