Airflow Vibrato Dependence on Pitch, Loudness, Adduction, and Straight Tone: A Single Case Study

The purpose of this study was to examine the relationship between airflow vibrato (primarily extent) and pitch, loudness, and adduction, as well as the differences between vibrato production and straight tone singing. A single professional mezzo soprano was the participant. A Glottal Enterprises aerodynamic system was used to record wide-band airflow. Results indicated that airflow vibrato extent tended to increase with pitch and loudness and decrease with greater adduction. The standard deviation of the airflow signal (including both the vibrato conditions and straight tone conditions) tended to increase with increase in the standard deviation of the fundamental frequency signal. Straight tone productions have small airflow variations that appear random, but acoustically contain the fundamental frequency and at least 10 additional harmonics of the intended sung pitch. Average airflow was higher for vibrato productions than for straight tones by about 17%.