There are many possible sources of perturbation and fluctuation in the voice. True False 3. True False 4. Shimmer is long-term variability in amplitude. True False 5.
Vibrato involves both frequency and amplitude modulation.
True False 6. Normal vibrato rate is from 2-4 Hz. True False 7. The difference between trill and vibrato is that the average pitch is raised in vibrato, but not in trill. True False 8.