Some Relationships between Vocal Effort and Intraoral Air Pressure
Raymond H. Colton, Wendy S Brown · The Journal of the Acoustical Society of America · 1973
Previously, Wright and Colton [J. Acoust. Soc. Amer. 51, 141 (1972)] described a power function between vocal effort and SPL that was concave downward with the knee of the function occurring apparently at the subject's most comfortable effort level. A similar function was noted for effort and fundamental frequency. In this study, a similar paradigm was utilized to explore the relationship between effort and intraoral air pressure. Vocal effort for the CVs /da/ and /ta/ was measured by magnitude estimation and production; intraoral air pressure was sensed with a tube-transducer system. Minimum, most comfortable, and maximum effort levels were also determined. The results show that vocal effort is a power function of intraoral air pressure. Furthermore, the function shapes were very similar to those reported by Wright and Colton; the change of slope tended to occur at the most comfortable effort level. Males tended to show the typical function; females tended to display a more straight function. These results tend to suggest the possible existence of two mechanisms involved in varied effort levels, since air pressure rises more rapidly below comfort level than above.