Voice researchers’ interest for non-operatic vocal techniques has

increased substantially over the last decade. A description of a vocal

style requires specification of voice source and formant characteristics,

data which mostly can be derived from inverse filtering the radiated

sound.

The voice source is heavily influenced by subglottal pressure, i.e., it

varies substantially with vocal loudness. Björkner (2007) compared voice

source characteristics as function of subglottal pressure in musical

theatre and opera singers and observed differences in pressure range and

in glottal adduction. Hein (2009) compared the respiratory characteristics

in professional musical theatre singers’ belting and legit styles and

found a great inter-individual variability.

The voice source is heavily influenced also by glottal adduction and vocal

fold length and tension, physiological voice control factors that control

type of phonation and pitch, respectively. Hence, the voice source

characteristics of a style can be described in terms of three-dimensional

graphs with pitch frequency, subglottal pressure and glottal adduction as

the three axes. In such a graph, a given style will be represented by a

cloud, the centre of gravity and diameter of which reflect the average and

standard deviation of pitch, pressure and adduction used in this style.

Some promising attempts to describe vocal styles in such graphs will be