Lessons in Music Form. Percy GoetschiusЧитать онлайн книгу.
these two rhythmic species underlies the movement to which he is listening. It is fairly certain to be one or the other continuously. Of duple measure, the march and polka are familiar examples; of triple measure, the waltz and mazurka. The "regularity" of the former rhythm imparts a certain stability and squareness to the entire piece, while triple rhythm is more graceful and circular in effect.
(2) The same dynamic distinction applies also to whole measures, and
(3) to accents. The first of two successive measures, or of two or more accents, is always a trifle heavier than the other.
(4) The melodic contents of the first measure may be exactly reproduced in the succeeding measure; but if this is the case, they are very unlikely to appear still again in the next (third) measure, for that would exaggerate the condition of Unity and create the effect of monotony.
[Illustration: Example 1. Fragment of Folk-song.]
The measure marked b is exactly like a. But c is all the more contrasting, on account of this similarity.
Or, the melodic contents of a measure may be thus reproduced, as far as the rhythm and direction of the tones are concerned, but—for variety—they may be shifted to a higher or lower place upon the staff, or may be otherwise modified.
[Illustration: Example 2. Fragment of Beethoven.]
Compare the groups marked a and b, and observe how the principles of unity and variety are both active in these four measures, and how their effect is heightened by the formation of c.
(5) The figures of the accompaniment, though reproduced in uniform rhythmic values and melodic direction, undergo constant modifications in pitch and in shape, similar, to those shown in Ex. 2. See, again, No. 37 of the Songs Without Words and note the changes in the formation of the otherwise uniform six-tone groups.
LESSON 1.—The student is to study this chapter thoroughly, and write answers to the following questions; if possible, without reference to the text:—
1. What does Form in music mean?
2. Define the conditions which constitute good form.
3. When is a composition faulty in form?
4. What do discriminating listeners recognize in music?
5. What is the difference between the sounds of music and those of language?
6. How does this prove the necessity of form?
7. By what is the presence of form in music shown?
8. What is the beat?
9. What is the measure?
10. By what means are the measures indicated, (1) to the reader; (2) to the listener?
11. To what does the further multiplication of the beats give rise?
12. What are cadences?
13. What purpose do they serve in music?
14. What is the best general name for a melody?
15. What object does it fulfil in music form?
16. What are the two vital requisites upon which the enjoyment of an art creation depends?
17. What purpose does Unity serve?
18. What purpose does Variety serve?
19. What is the great problem of the art-creator?
20. Define the conditions that confirm the principle of unity in music.
21. Define the evidences of variety in music.
CHAPTER II. FUNDAMENTAL DETAILS.
TIME.—Time is the same thing in music that it is everywhere else in nature. It is what passes while a piece of music is being played, sung, or read. It is like the area of the surface upon which the musical structure is to be erected, and which is measured or divided into so many units for this, so many for that, so many for the other portion of the musical Form. Time is that quantity which admits of the necessary reduction to units (like the feet and inches of a yardstick), whereby a System of Measurement is established that shall determine the various lengths of the tones, define their rhythmic conditions, and govern the co-operation of several melodies sung or played together. Time is the canvas upon which the musical images are drawn—in melodic lines.
TEMPO.—This refers to the degree of motion. The musical picture is not constant, but panoramic; we never hear a piece of music all at once, but as a panorama of successive sounds. Tempo refers to the rate of speed with which the scroll passes before our minds. Thus we speak of rapid tempo (allegro, and the like), or slow tempo (adagio), and so forth.
BEATS.—The beats are the units in our System of Measurement—as it were, the inches upon our yardstick of time; they are the particles of time that we mark when we "count," or that the conductor marks with the "beats" of his baton. Broadly speaking, the ordinary beat (in moderate tempo) is about equivalent to a second of time; to less or more than this, of course, in rapid or slow tempo. Most commonly, the beat is represented in written music by the quarter-note, as in 2–4, 3–4, 4–4, 6–4 measure. But the composer is at liberty to adopt any value he pleases (8th, 16th, half-note) as beat. In the first study in Clementi's "Gradus ad Parnassum," the time-signature is 3–1, the whole note as beat; in the 8th Sung Without Words it is 6–16, the sixteenth note as beat; in the last pianoforte sonata of Beethoven (op. 111), last movement, the time-signatures are 9–16, 6–16, and 12–32, the latter being, probably, the smallest beat ever chosen.
MEASURES.—A measure is a group of beats. The beats are added together, in measures, to obtain a larger unit of time, because larger divisions are more convenient for longer periods; just as we prefer to indicate the dimensions of a house, or farm, in feet or rods, rather than in inches.
Measures differ considerably in extent in various compositions, inasmuch as the number of beats enclosed between the vertical bars may be, and is, determined quite arbitrarily. What is known as a Simple measure contains either the two beats (heavy-light) of the fundamental duple group, or the three beats (heavy-light-light) of the triple group, shown in the preceding chapter. Compound measures are such as contain more than two or three beats, and they must always be multiplications, or groups, of a Simple measure; for whether so small as to comprise only the fundamental groups of two or three beats (as in 2–4, 3–8, 3–4 measure), or so large as to embrace as many as twelve beats or more (as in 4–4, 6–4, 6–8, 9–8, 12–8 measure), the measure represents, practically, either the duple or triple species, Simple or Compound. Thus, a measure of four beats, sometimes called (needlessly) quadruple rhythm, is merely twice two beats; the species is actually duple; the alternation of heavy and light pulses is regular; and therefore the third beat is again an accent, as well as the first, though less heavy. A measure of 6–8 is triple species, with accents at beats one and four, precisely as if an additional vertical bar were inserted after the third beat. In a word, then, the size of the adopted measure is of no consequence, as long as it is retained uniformly through the section to which it belongs;