Voice intensities in fortissimo and pianissimo were measured at various pitches with a high speed level recorder. The data were recorded on a graph of which horizontal scale indicated pitches and vertical scale indicated intensities in desibels. This graph was named a “phonogram ”. The “volume of voice” was obtained from a voice intensity curve in fortissimo phonation at !various pitches. In this study, it was calculated from the area between the fortissimo line and the 70 dB SPL line. Voice characteristics of each subject were visualized by a figure enclosed with two curves obtained in pianissimo phonation and fortissimo phonation at various pitches. The size of this figure gives an “effective value of voice ”. The examinations were performed in 139 healthy subjects. Their ages were from 6 to 30 years old. The same examinations were also carried out in 54 cases with laryngeal disorders. The results were as follows:
1. The volume of voice appeared to greatly increase between ages of 10 to 14.
2. The effective value of voice gradually increased after 8 years old in the male and 10 years old in the female.
3. In healthy subjects, the voice intensity proportionally increased as the pitch of voice increased.
4. Intensity range of voice between pianissmo and fortissimo phonation at varirus pitches showed the maximum at a slightly higher pitch than the speech range.
5. Changes in intensity of voice were marked in the register transition.
The pattern of the phonogram may offer more valuable informations evaluating voice characteristics and disorders than the conventional examinations of voice and the classifi- cation of hoarseness with “semantic differential method”.
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