Moreover, as the voice progresses upward through the scale, three distinct physical sensations are experienced by the singer according as to whether he is singing low, middle or high. There is one physical sensation for the lower, another for the
middle and a third for the higher notes. This would indicate that there is, after all, more of a change in the adjustment of the vocal tract for the middle notes than is apparent superficially, and confirms the position of those who hold that there are three vocal registers instead of two.
In voice-production of the lower notes there is a physical sensation of vibration in the upper chest; on the medium notes, in the pharynx; on the higher notes, in the head. These physical sensations have determined the names of chest register for the lower and head register for the higher range of tones. Strictly speaking, the middle range should be denominated pharyngeal or throat register, but usually it is called the medium or middle register. In the chest register the vibrations of the vocal cords are slow and heavy; the vocal tract being in its relaxed, open adjustment, the larynx sinks slightly and, the vibrations taking place in their nearest proximity to the chest, they are communicated to it. In the middle register the adjustment of the vocal tract is more closed than in the chest register, the larynx rises a little, the shape of the vocal tract is determined largely by the relative positions assumed by the epiglottis and the soft palate, and the vibrations no longer can communicate themselves
to the chest, but are felt in the pharynx. In the head register the vocal cords come together at one end, sometimes at both ends, and only the upturned edges of the resulting small aperture vibrate, throwing the sensation of vibration up into the head. In every way Nature seems to indicate that there are three vocal registers.
The most extreme limits of human voice so far known were found in the voices of Ludwig Fischer, a bass singer, and of Lucrezia Agujari (La Bastardella), a florid soprano. Fischer created the rôle of Osmin in Mozart's "Entführing aus dem Serail." His voice went down to contra F
an entire octave lower than the ordinary bass singer. La Bastardella sang as high as
