Dynamic voice source analysis
A number of adult singers have been investigated to identify whetehr or not there are voice source features that vary as a function of singing training and experience. The electrolaryngograph has been used to measure larynx closed quotient, or CQ, (the percentage of each cycle for which the vocal folds remain in contact). Results demonstrate that there are patterned differences with respect to both gender and the degree of singing training/experience.
The plots below are for a trained and untrained adult female, left and right respectively (Howard, 1995). CQ is plotted against fundamental frequency (f0) as a scattergram (Qx). Note the variation of CQ is very different with f0 between the trained and untrained subjects. In particular, the trained subject exhibits a steeply rising CQ with f0 to CQ values in excess of 70%, whereas the untrained subject has steeply falling values of CQ with rising f0 to values below 20%.
Adult males generally exhibit a constant value of CQ with f0 which is higher for greater degrees of singing training/experience. In addition, CQ values for trained adults tend to be greater that their CQ values for speech whereas untrained adult males exhibit CQ values that are lower than their speech CQ values. Summary findings for adult females and males are plotted below. These are based on the overall shape of the Qx plots (compare the trained and untrained ends for adult females with the examples above).
