Now we come to the "Registers" of the voice. I have defined a register as "a series of tones produced by the same mechanism." The five registers of which the human voice, taken as a whole, consists, are carefully described, and the means by which they are formed minutely explained in a former part of this book. These registers, nevertheless, continue to be a stumbling-stone to many, and the fact of the existence in the throat of different actions for the production of different series of tones has led some teachers into the deplorable mistake of developing and exaggerating them, instead of, on the contrary, smoothing them over and equalizing them. The result is that we often hear singers who seem to have two or three different voices. They are growling in the one, moaning in the second, and shrieking in the third; while it should have been their aim so to blend and to unite the registers as to make it difficult even for a practised ear to distinguish the one from the other. Such singing is outrageous, and I protest against the opinion expressed in some quarters that it is the natural outcome of the teachings of the laryngoscope.
In developing and strengthening the registers I base my first exercises upon the fact that the "Vowel Scale" goes from low to high in this order; oo, oh, ah, ai, ee, so that consequently the highest tones will be produced most readily when singing the vowels in the order just given.
Sing this exercise quite softly, strike each tone clearly and distinctly, and take a slight inspiration after every tone. Be careful to take a full inflation only at the beginning, and afterwards to inhale less air than has been consumed in every preceding tone, or you will after a while overcrowd the lungs, and experience a sensation of being choked. This is a thing to be avoided in any case; but under present circumstances it should be remembered that the short inspirations are not taken for the purpose of re-filling the lungs, but simply to compel the "opening and closing muscles" to do their work. By so doing we give them six times more exercise than by breathing only once at the beginning; and, what is more important still with regard to our immediate object, we greatly facilitate the task of the vocal ligaments to arrange themselves in different ways according to the registers they are to produce.
It is self-evident that the danger of carrying the mechanism of a register beyond its proper limit is greater if the vocal ligaments are kept together, than it would be if they were made to separate, thereby being enabled to close again under different conditions. It will be seen, therefore, that the slight inspirations after every tone are an essential part of the exercise, and must on no account be omitted. The exercise is to be taken at a convenient pitch, and then to be raised semitone by semitone in accordance with the requirements of individual voices. It may, after some time, be taken right through upon the vowel ah, and finally legato, gradually increasing the speed, to the Italian word scala, singing the syllable la to the last note.
The change from one register to another should always be made a couple of tones below the extreme limit, so that there will be at the juncture of every two registers a few "optional" tones which it is possible to take with both mechanisms. The singer will be wise, however, to avail himself of the power of producing an optional tone with the mechanism of the lower register only on rare occasions. To force the register beyond its natural limit is, of course, infinitely worse, and should never be tolerated. The practice carries its own punishment, as it invariably ruins the voice; and tones so produced always betray the effort (frequently in a most painful degree), and are consequently never beautiful.
It is to be observed that the exercise given above may be varied to any extent, so long as it is based upon the principle which has been explained. The beneficial results in the development of the voice will speedily be noticed, and then sustained tones may be sung through the whole compass after the orthodox fashion.
This brings me to the consideration of the "mixed voice," which is essential in bridging over the break between the "upper thick" and the "lower thin" of the tenor, and which is also frequently made use of by baritones and basses in the production of their highest tones.
The "voce mista" is "mixed" in this sense, that it combines the vibrating mechanism of the "lower thin" with the position of the larynx of the "lower thick;" that is to say, while the vibrations are confined to the thin inner edges of the vocal ligaments, the larynx itself takes a lower position in the throat than for the "lower thin," and the result is a remarkable increase of volume without any corresponding additional effort in the production of tone. A few trials before a looking-glass will at once prove the correctness of this explanation, and, what is of more practical consequence, will enable the student with a little practice to overcome the serious difficulty of singing high tones without straining, yet with a fulness capable of being increased or diminished at pleasure.