Gender differences in children's singing voices: acoustic analyses and results of a listening test.

This study tested the hypothesis that acoustic parameters exist which are specific to gender in children's singing voices, and that these parameters are relevant to listeners' identification of gender of children's singing voices. A listening test was run with examples of singing produced by children belonging to different singing cultures, six boys and six girls from a Swedish music school and six boys from an elite German boys' choir. Sustained vowels were analyzed with regard to formants and voice source properties (jitter, shimmer and glottal-to-noise-excitation rate, closed quotient, and normalized amplitude quotient). Most of the measured parameters differed significantly between the boys belonging to the two different singing cultures. Regarding boys and girls from the same choir, only the closed quotient and the fourth formant frequency differed significantly. The listening test was carried out by an expert panel. The listeners correctly identified the gender of the singer in 66.0% of the cases, i.e., far better than chance. A multiple linear regression analysis revealed that the listener's answers correlated well with the formant frequencies, with the fourth formant showing the highest correlation.