In previous articles we have dealt with musical form already in terms of movement and arrival, the distribution of melodic material, and the layout of keys. Here we shall begin to explore it in greater depth, to approach the complete experience — the “when,” “what,” “where,” and “how” — of musical form.
This articles will cover the roles of rhythm, melody, harmony, and texture in what you as the listener perceive to be musical form. Next article will then apply these insights to a survey of traditional forms.
Rhythm as Form
Rhythm is the most basic element in musical form. Because it manages musical time, it is the common denominator for all the other processes of musical form — melody, harmony, and texture. Rhythm operates on every level of magnitude, from the simplest two-note figure to the total structure of a symphony. Rhythm is the “when” of musical form. The most pervasive role of rhythm in musical form is to mark off two kinds of time blocks: phrases and periods. In the process, rhythm performs two vital functions: it separates substantial sections for clarity, and it links them for continuity.
Phrases and periods in music have counterparts in language. A phrase is comparable to a clause in a sentence: it contains a distinct idea, but is not a complete thought. A period is comparable to a sentence, in which the thought is complete. Just as in language, phrases and periods in music have no prescribed lengths. In music associated with poetry and dance, however, phrases and periods do help arrange the musical material into a symmetry. The simplest and most familiar pattern is to link two phrases of equal length. The first phrase has an open ending; the second phrase closes the action and finishes the period. Example 1, from Mozart’s Sonata in A Major, is a model for this kind of form. Mozart made it totally symmetrical; if you divide it continually you will find pairings that descend to the half-measure level. On the other hand. Example 2, from the Haydn Sonata in Eb Major, is most irregular. Its first two measures form a phrase that, by itself, has a certain completeness of thought but that is too short to be a real period.
Regular period. Mozart: Sonata in A Major, first movement.
Irregular period. Haydn: Sonata in Eb major, first movement.
For balance (but not for symmetry), Haydn then plays with echo figures that make a sort of patchwork phrase. In Mozart’s sonata we can predict the exact instant of arrival. In Haydn’s sonata we are at the mercy of the composer, to arrive at what he considers the most telling moment. These two examples make it quite clear that a period is completed only when the music arrives at some effect of finality.
Composers project rhythm on a larger scale as they deploy events throughout a piece — striking contrasts, effective recalls of material, the spinning-out of movement or its abrupt halt. And exponentially, as we move up the scale of magnitude, we enter the world of macro-rhythm: the timing of principal sections and of entire movements.
Melody as Form
Melody, the most easily recognized element in music, serves musical form as a landmark. When a composer recalls or rhymes a well-defined theme, he establishes a connection that links both appearances. By such restatements he unifies the form and makes it more intelligible for the listener (as discussed more fully in The Process of Melody).
Contrast of melodic ideas is another way that a composer organizes musical form. He can do this at short range, where a tug-of-war between sharply differentiated figures kicks off a long-range action (This Example illustrates such a contrast). With contrast a composer can also mark off large sections of a composition. In Example 3, Mahler casts the first theme in a minor key and in the rhythm of a solemn, majestic march for a dark mood. The theme inhabits the middle and lower ranges of pitch and is frequently interrupted by brief pauses. Shortly thereafter the dark mood evaporates and a completely different melody enters. The second theme flows upward, songlike and glowing, in a major key far removed from the brooding minor of the first theme, as if it came from another world and another time.
Thematic contrast in musical form. Mahler: Symphony no. 2 in C Minor. a) First theme.
Thematic contrast in musical form. Mahler: Symphony no. 2 in C Minor. b) Second theme.
Melody — easily recognized by the listener due to its clear shape and specific manner — thus acts as the “what” of musical form. It is the surface of a passage, creating the profile of the ongoing action.
Harmony as Form
Harmony is involved in musical form through the location of keys in a piece. When, for example, the composer begins a piece in C major, modulates to G major, then brings the music back to close in C major, he is creating a harmonic form for his music. (This plan is sketched in this Example) The movement to and from keys gives the music direction. Figuratively, therefore, we can say that harmony represents the “where” of musical form.
Western music for the past three centuries has based its harmonic forms on just such movements between keys. Among these movements, certain routes have taken precedence, so much so that they control most eighteenth-century music and a great deal of the music written since then. In themselves these routes are quite simple. Example 4 illustrates one of the preferred plans in a rather crude way. You hear four progressions, each of which by itself gives you a clear and firm sense of its key by beginning and ending on the chord that gives the key its name. The four progressions in order comprise a harmonic form that makes a tour of keys, beginning and ending in the first key. In a very simple way, this example fulfills expectations that a piece will end in the same key in which it began, thus closing a harmonic circle. As you listen to it, concentrate on the bass notes. They support the harmony and give solidity to important points of arrival in each key. Notice especially those notes marked with squares. They are the tonal centers, or the “tonic” notes, for their respective keys (see also this Example).
Basic key scheme (major chords in capital letters; minor chords in lower case letters).
Example 4 makes its point painfully clear; its very roughness highlights the departure from and the return to the home key. Musically, though, it won’t work except as a parody. To make it work a little better, Example 5 smooths out the connections from chord to chord, adjusts the positions of the chords themselves, and supplies connecting links to bridge the harmonic gaps between keys. Notice also that the return to C at the end is reinforced by several more cadential effects in order to confirm the impression of final harmonic arrival. In both Example 4 and Example 5, you hear the harmony moving to a third key, A minor. This harmonic movement erases the effect of G major and raises a question as to what will follow. The music answers this question and closes the cycle of action by returning to C major.
Basic key scheme with smooth connections.
The plan of keys given in these two examples is a virtual genetic code of harmony for the majority of compositions written from 1750 to about 1850, the principal period from which our listening repertory is taken. In this code, the first two keys are fixed: if the home key (I) is major, the second key will be V (the dominant if the home key is minor, the second key will be III (its relative major). The third part of the harmonic plan, represented in this case by A minor, is open to many different routes, so much so that this section is best designated by the letter “x”, signifying that a great number of options are available to the composer. The final section is fixed — it comes home to I. Therefore, we can symbolize the harmonic form as follows: I-V; “x”-I for the major key and I-III; “x”-I for the minor key. (The semicolon signifies the final point of arrival in the second key — an important point of punctuation — matched later on by the final point of arrival in the home key.)
The beauty of this plan is its flexibility within an unshakably firm framework. In short pieces, dances, marches, and songs it traverses its route in a short time, perhaps no more than a minute or two. But it also underpins the form of great symphonic movements, which may occupy over ten minutes. The plan can accommodate an incredible variety of melodic material. Example 6 presents a model of the I-V; “x”-I form, beautifully shaped by Mozart as a theme for a set of variations. This example also gives the melodic plan to show how neatly the harmonic and the melodic layouts merge.
Model of the I-V; “x”-I form. Mozart: Sonata in D Major, third movement.
In the first movement of his Symphony no. 3 Beethoven applies the same plan on a much grander scale. Assuming that each measure takes one second, the phases of harmonic action take approximately the following amounts of time:
|I||first key||40 seconds|
|connection to second key||16 seconds|
|V||second key||one minute, 49 seconds|
|“x”||optional key (or keys) to guide return to I||four minutes, 8 seconds|
|I||return to first key||five minutes. 54 seconds|
Notice that Beethoven devotes more time to each succeeding principal phase. He does so in order to accomplish two objectives: to erase the impression of what has gone before and to confirm the new harmonic position. This range of proportions is particularly effective in longer works, where the composer uses them to build powerful thrusts to important points of harmonic arrival, especially the final arrival at the home key. Meanwhile tremendously rich melodic material, rhythmic manipulation, and textural play can ride upon the harmonic drive.
The I-V; “x”-I trajectory described above spans the entire form of a movement, small or large. Composers also incorporate various cycles of departure and return into sections (periods and groups of periods) within a movement. If we imagine Example 5, the “genetic code,” expanded into the first phase of a large work, we experience all the action between the first and last chords as a presentation of the home key, an arc with its own inner crises and resolutions. The next phases of the large work, V, “x”, and I, will also have their own arcs on a comparable scale. Thus the great harmonic form will emerge, with the encompassing wide arc reaching from the beginning of the piece in I to its ending in I.
Another and often more striking way a composer works with harmonic phases is to piece together several short harmonic arcs. He introduces harmonic digressions after a brief statement of the first phase, then returns rather quickly to the home key. For example, Beethoven, in the second movement of his Symphony no. 5, makes a sudden brilliant harmonic shift along with a bold change of mood from lyric to martial (Example 7). He then carefully — indeed rather mysteriously — weaves a return to a recall of the first phase. He now does the same thing again, so that the greater part of the movement can be symbolized as an A B A B A form with short harmonic arcs.
Sudden harmonic shift. Beethoven: Symphony no. 5, second movement.
You can easily appreciate such bold, local changes of key, much more readily than you can follow the subtle long-range movement of keys in the I-V; “x”-I plan. Both of these kinds of modulation play important roles in musical form, either to highlight changes of mood and color or to build a coherent harmonic form for an entire piece.
Encouraged by the richer tone qualities developed in the orchestra and the piano, composers in the nineteenth century began to concentrate on the color of harmony. Schubert was among the first to explore this harmonic resource intensively. Much of the appeal of his music lies in his luminous effects of harmony highlighted by kaleidoscopic shifts of color, as in the opening of his Quintet in C Major. As composers became more interested in effects of harmonic color, they became less bound to key-centered action. This was an effective trade-off: when you hear a striking harmonic effect, you feel little urgency for that sound to progress forward to a specific tonal center. By the turn of the twentieth century, key as a controller of form — though it still held on in much music — no longer commanded the action as completely as it had in earlier times.
Twentieth-century composers continued this movement away from key-centered harmony. The most important of these were Arnold Schoenberg and his followers and the so-called avant-garde composers of the post-World War II period: Karlheinz Stockhausen, Pierre Boulez, Luigi Dallapiccola, among many others. Bela Bartok, on the other hand, synthesized many elements from music of the past with twentieth-century techniques. His treatment of harmonic form in his Music for String Instruments, Percussion, and Celesta can be quickly grasped by the listener. The tonal center for the first movement is A; the harmony moves steadily away from A until it reaches Eb, then the tonal center recedes back to A. The entire form thus makes an arch. (Notice that, as a twentieth century composer, Bartok goes to the musically distant note Eb for his tonal contrast, instead of to the dominant, E, which earlier composers would have used.) In the finale, set in the style of a folk dance, the harmony returns several times to the home key after short, highly contrasted digressions. Thus, Bartok has adapted the two traditional harmonic plans — the long-range trajectory and the short arcs — to his own style.
Texture as Form
Texture clarifies form. It is the “how” of form. Through changes in voicing, range, tone color, and action, it marks off individual phrases and periods. This function of texture was put to use in the earliest Western music of which we have any record, Gregorian chant. As a chant was being performed, the responses between a solo singer and a group of singers articulated the form of the song simply through the amount of sound being produced. For centuries such alternations between segments of an ensemble have served a clarifying purpose in musical form. One form that depended heavily on this trade-off was the concerto of the Baroque era. Its textural layout alternated solo and tutti (full ensemble), while the harmony circled around various keys related to the home key. The first movement of Bach’s Brandenburg Concerto no. 2 is a model for textural layout in the Baroque concerto, with its give-and-take between the full orchestra and the four soloists: violin, trumpet, flute, and oboe. The textural contrasts are highlighted by the different tone colors of the solo instruments: suave in the violin, light and bright in the flute, brilliant in the trumpet, edgy in the oboe.
Whirlpools by M.C. Escher.
The increased range of pitch, color, and amount of sound that evolved in instruments from about 1770 onward gave Classic, Romantic, and modern composers the means to exploit textural values even more thoroughly. Beethoven gives different colors to the three presentations of his opening theme in the first movement of his Symphony no. 3: broadly singing violoncello tone; light, lyric flute tone; and powerful brass tone, respectively. All three statements are in the home key of the piece. The textural changes add a profile of color to the melody, the harmony, and the rhythm.
Large-scale works of the Romantic era carry textural distinctions further. Tchaikovsky, in the first movement of his celebrated Symphony no. 6, the Pathétique, supports striking contrasts of effect with bold contrasts of texture. The slow introduction is essentially a procession of low-pitched darkly colored chords proper to the lugubrious mood; the allegro that follows gets embroiled with a furious give-and-take; this then subsides, giving way to a broadly flowing melody supported by intensely sweet harmonies.
Twentieth-century composers also rely heavily on textural contrasts to delineate various sections of a form. Stravinsky characterizes each of the episodes in Le Sacre du Printemps by its own orchestration. Bartok makes brilliant use of textural values to mark off principal sections in the first movement of his Music for String Instruments, Percussion, and Celesta. The first two-thirds of this movement is densely contrapuntal, building a thick texture with constant imitations. At the climax of the movement, the dense counterpoint suddenly dissolves and the whole orchestra comes together on a single note, doubled in several octaves. Now the counterpoint resumes, but more sparsely until the music reaches its home key. Here the bell-like celesta enters with a spread of light, rapid notes, creating a misty curtain of sound. This veil of sound freezes the counterpoint, which then becomes like arabesque figures against a background — moving, but going nowhere. Thus, Bartok has used texture to clarify the phases of the form — departure, arrival at a point, and return to home base.
In summary, we might say that rhythm is the driving power of form, its instant-to-instant thrust; melody and texture articulate form, establishing landmarks and other topography; and harmony is the great chain, the unbroken line that goes from here to there and back again.