Voice classification and vocal tract of singers: A study of x-ray images and morphology

TLDR

The study compares vocal tract dimensions and voice classification in Dresden solo‑singing students using a 1959–1991 x‑ray archive. The authors analyzed 132 x‑ray images, measuring vocal tract, pharynx, mouth cavity, larynx position, palatal arch height, vocal fold length, and correlated these with body height, weight, and BMI. They found that pharynx length strongly influences total vocal tract length and that singers of different voice classifications exhibit consistent morphological vocal tract differences.

Abstract

This investigation compares vocal tract dimensions and the classification of singer voices by examining an x-ray material assembled between 1959 and 1991 of students admitted to the solo singing education at the University of Music, Dresden, Germany. A total of 132 images were available to analysis. Different classifications’ values of the lengths of the total vocal tract, the pharynx, and mouth cavities as well as of the relative position of the larynx, the height of the palatal arch, and the estimated vocal fold length were analyzed statistically, and some significant differences were found. The length of the pharynx cavity seemed particularly influential on the total vocal tract length, which varied systematically with classification. Also studied were the relationships between voice classification and the body height and weight and the body mass index. The data support the hypothesis that there are consistent morphological vocal tract differences between singers of different voice classifications.