The author would also insist, in the most emphatic manner, on the great importance of making all such exercises musical. Every tone should be the best then possible to the voice-user, and power must on no account be aimed at for some time. Thus are developed and go hand in hand, as they always should, a sound technique with the artistic conscience and perceptions.
SUMMARY AND REVIEW.
The Principles of Physics, etc., Involved.
Sound (tone) is a mental result having its origin in certain changes in the ear and the brain, owing to vibrations of the air. Tones have pitch, depending on the number of vibrations in a second, volume (power), depending on the size of the waves or vibrations, and quality (timbre), determined by the shape of the waves. Pitch is determined by the vocal bands, volume by the same, in great part, and quality by the shape of the resonance-chambers above the vocal bands. The resonance-chambers influence volume also. A tone is augmented by resonance.
The larynx bears certain resemblances to both stringed and wind instruments, but it is really unique (sui generis). The vibrations of the vocal bands are caused solely by the expiratory current of air, which is more or less held back by the cords, owing to their approximation, so that the greater the obstruction the stronger must the blast of air be, other things being equal, and the result increase in pitch. The problem Nature had to solve is very complex.
The laryngoscope was invented in 1854 by a teacher of singing, Manuel Garcia, who soon after gave an account of it to the Royal Society of England. The instrument consists essentially of two mirrors, the external, or "head-mirror," which is concave and reflects into the larynx, and the internal, or "mouth-mirror," which reflects the picture outward to the eye. The latter mirror is plane, and set at an angle. The picture may show, under the most favorable circumstances, all the upper parts of the larynx, including the vocal bands, but sometimes, also, the windpipe as far down as its division into the two main bronchial tubes. The difficulties commonly met with in the use of the instrument are a constrained action of the throat and mouth parts of the subject, unnatural breathing, an unruly tongue, etc. The epiglottis may, also, naturally so overhang the glottis that a good view of the vocal cords is impossible. It is difficult to see more than one-half to two-thirds of the length of the vocal bands. The picture seen is that of the parts of the larynx reversed—i.e., while right remains right, posterior becomes anterior. The laryngoscope shows that (1) in singing an ascending scale the vocal bands are for a certain time in action (vibration) throughout their whole length; that (2) there may be observed a rather sudden change when the vocal bands are relaxed and shortened, and that this process of shortening goes on, the bands approaching more and more, both behind and in front, till (3) in the highest tones of a soprano of great range there is only a small portion of each vocal cord toward the centre that is not approximated somewhat closely.
With certain qualifications, it may be said that the action of the vocal bands is alike for all voices. In all cases a certain degree of approximation of the vocal bands is absolutely necessary for phonation, and the mechanism is generally similar in males and females till the highest tones, above alluded to, are reached. This is in harmony with the following facts: (1) The crico-thyroids are the muscles most in use in ordinary speech and in singing the lower tones. (2) Several muscles combine in relaxing and shortening the vocal bands. (3) The peculiar mechanism of the highest tones in a soprano voice of great compass is only to be explained by a combined action of several muscles, and a very delicate and precise use of the internal thyro-arytenoids attached along the whole length of the outer surface of the vocal bands. The larynx of the male differs from that of the female chiefly in its greater size, weight, etc. The vocal bands in the male may measure from three-fifths to four-fifths of an inch when relaxed, and from four-fifths to one inch when tense; in the female, from two-fifths to three-fifths of an inch when relaxed, and from three-fifths to four-fifths of an inch when tense. There are structural differences corresponding to and determining the kind of voice, as to range and power more especially. The bass singer has, as a rule, the largest larynx and the longest and heaviest vocal bands.
Fig. 45. Represents what the author has frequently seen, by the use of the laryngoscope, when a soprano is producing a very high head-tone, say C, D, or E in alt. It will be observed that the vocal bands approximate in front and behind ("stopped"), so that the only parts of the bands capable of vibration are those short portions which form the margins of the oval opening shown in the illustration. Only a very limited number of singers are capable of the delicate adjustments required.
At puberty the changes that take place in the body generally are associated with corresponding alterations in the larynx. The larynx grows, changes its proportions, etc., often somewhat rapidly, and the result may be a corresponding alteration in voice, as regards range, power, and quality. The voice, because of imperfect anatomical and physiological adjustment, may "break," to a greater or less extent. The same may take place, owing to similar imperfect adjustment, in old age, and temporarily, owing to disease, weakness, nervousness, fatigue, faulty production, etc. These facts indicate that under such circumstances the voice should be used with great care, not at all, or in a whisper, when the vocal bands are practically not in action.