Subglottal Pressure and Airflow Measures During Vocal Fry Phonation

Simultaneous recordings of the voice signal, intertracheal air pressure, and rate of airflow were obtained from five adult male subjects during three sustained phonations of the vowels /a/ and /i/ at three regions within their vocal try range and two within their modal (mid) phonational range. The subglottal pressures produced during vocal fry were significantly greater than those produced at adjacent frequencies in the modal range. In addition, subglottal pressure increased with increases in repetition rate. No significant difference was found between /a/ and /i/ produced at any one fry condition. Rate of airflow was significantly lower in fry phonation than in modal, and no relationship between flow rate and frequency in either range was found. The aerodynamic relationships suggest that during sustained vocal fry, subglottal pressure builds to open the apparently massive vocal folds quickly, while the low flow rate may be related to the long closed phase of the vocal folds.