Airflow Vibrato: Dependence on Pitch and Loudness

To describe the airflow vibrato characteristics at various pitches and loudness levels during vocal vibrato production.

This descriptive case series research design included four subjects: 1 baritone, 1 tenor, and 2 sopranos. The extent and rate of airflow vibrato and fundamental frequency vibrato were measured by analyzing /pa:pa:pa:p/ strings with at least 3-4 cycles of vibrato during the vowels. Comparison was made within and between the subjects at different pitches and loudness levels.

Airflow vibrato was quite evident for all subjects. Mean airflow vibrato extents were larger in female than male singers. Increase in airflow vibrato extent was observed with increase in pitch, and it was statistically significant when comparison was made within each subject, within males (for P2, M = 74.55 cc/s, S.D = 27.44 cc/s, p < 0.01), within females (for P2, M = 94.36 cc/s, S.D = 24.13 cc/s, p< 0.01), and between males & females (for P1 in females, M = 46.96 cc/s, S.D = 16.16 cc/s, p < 0.003; for P2 in females, M = 94.365 cc/c, S.D = 24.13 cc/s, p < 0.02). Statistically significant increase in airflow vibrato extent was observed between males and females only at the highest loudness level (for females, M = 81.77 cc/s, S.D = 23.80 cc/s, p < 0.0001). The range of phase difference between them was 34°-197°, and most of the time, airflow vibrato lead F0 vibrato. EGG values were also reported.

This study shows that the characteristics of airflow vibrato are similar to F0 vibrato; i.e., airflow vibrato also has extent, rate, regularity, and waveform complexity. However, airflow vibrato waveforms were seen to be more complex in waveshape than F0 vibrato waveforms. Studies on the sources of airflow vibrato are necessary.