2.1 Acoustic structure of the singing voice
The main physical characteristics of singing voices include the tone pattern, dynamics and timbre of the voice.
The first one includes precision or clarity of high-pitch intonation; the vocal range, and its scale location.
The dynamic one deals with the dynamic range at different pitch levels, i.e. the difference between forte and piano sound at each high point of the range.
The timbre characteristics include the overtones or the spectral saturation of the sound, smoothness of transitions between the registers; sonority and power of the voice, its freedom and intensity of its sound, vocal placement, round character of the vowels, as well as the quality of vibrato.