Note: Dr. Arnold, a noted Viennese otolaryngologist and expert on voice pathology, enumerates quantifiable vocal factors: frequency groups (pitch), intensity (volume), and temporal distribution of sound (rhythm), visible on a graph as variable bursts of intensity as well as audible to the ear. A given physiology of the vocal apparatus determines sound production of quantifiable voice factors (such as natural ranges, size of resonator), but there are mechanisms for sound modification within the natural vocal ranges in male and female: chest, middle, and head voice. In the untrained male voice the break (change of resonators) between ranges (such as chest and head tones) shows on an oscillator as wild, uncontrolled vibrations. Human vocal pitch is modified through a stretching of the vocal chords, both of which must resonate together. High intensity (loudness) raises pitch. Singing highest notes pianissimo is summit of trained singer's art. Vocal dimensions have both fixed and variable aspects. Modification of overtones (timbre) involves damping and adjustments of the resonators (vocal color). Merits of a simple, four or five-point scale.