The term musical form is often loosely used to refer to particular musical genres or styles (Scholes 1977), which may be determined by factors such as harmonic language, typical rhythms, types of musical instrument used as well as historical and geographical origins. In the vocabulary of art-music, however, it has a more extended meaning, referring to the type of "architectural" structure on which the music is built. Scholes (1977) explained musical form as a series of strategies designed to find a successful mean between the opposite extremes of unrelieved repetition and unrelieved alteration.
Middleton (p. 145) also describes form, presumably after Gilles Deleuze’s Difference and Repetition (1968, translated 1994), through repetition and difference. Difference is the distance moved from a repeat, a repeat being the smallest difference. Difference is quantitative and qualitative — how far different and what type of difference.
Musical form may be contrasted with content (the parts) or with surface (the detail), but there is no clear line dividing them. "Form covers the shape or structure of the work, content its substance, meaning, ideas, or expressive effects" (Middleton 1999). In many cases form depends on statement and restatement, unity and variety, contrast and connection.
Levels of organization
The most basic levels of musical form concern (a) the arrangement of the [pulse] into accented and unaccented beats, the cells of a measure that, when harmonised, may give rise to the "briefest intelligible and self-existent musical unit" (Scholes 1977), called a motif or figure, and (b) the further organisation of such a measure, by repetition and variation, into a true musical phrase having a definite rhythm and duration that may be implied in melody and harmony, defined, for example, by a long final note and a breathing space. This "phrase" may be regarded as the fundamental formal unit of music: it may be broken down into measures of two or three beats but its distinctive nature will then be lost. Even at this level we can see the importance of the principles of repetition and contrast, weak and strong, climax and repose. (Macpherson 1930). (See also: Metre (music)) Given all this, we may understand the term "form" on three further main levels of organisation that we can roughly designate "passage", "piece", and "cycle" for purposes of exposition:
The smallest level of construction concerns the way musical phrases are organised into musical "sentences" and "paragraphs" such as the verse of a song. This may be compared to, and is often decided by, the verse-form or metre of the words or the steps of a dance.
For example, the twelve bar blues is a specific verse form, while common metre is found in many hymns and ballads and, again, the Elizabethan galliard, like many dances, requires a certain rhythm, pace and length of melody to fit its repeating pattern of steps. Simpler styles of music may be more or less wholly defined at this level of form, which therefore does not differ greatly from the loose sense first mentioned and which may carry with it rhythmic, harmonic, timbral, occasional and melodic conventions.
In the analysis of musical form, sections, units, etc. that can be defined on the time axis are conventionally designated by letters, as is the case in discussing poetic form. Capitals are used for the most fundamental, lower-case for sub-divisions. If one such section returns in a varied or modified form, a small digit or an appropriate number of prime symbols appears after the letter. Even at this most basic level we find patterns that may be re-used on larger time-scales. For example, the following verse:
- Twinkle twinkle little star
- How I wonder what you are
- Up above the world so high
- Like a diamond in the sky.
has a verse composed of two differently-rhymed couplets (AABB): its organization is twofold or binary. But in this one:
- There once was a fellow from Leeds
- Who swallowed a packet of seeds.
- In less than an hour he burst into flower
- And he died trying to pull up the weeds.
There is a rhyme repeated in the second line, but in the third we find a variant, two half-lines sharing a new rhyme, followed by a final return to the first arrangement in the last line, giving the four lines the form AABA. This "same-different-same" form in music is called ternary or threefold. However, as Macpherson points out (1930) there is a preference at all levels of musical organisation for groupings of two, four, eight over other divisions, so that even a "threefold" form is often extended by repetition of the first subject into a fourfold structure. Composers, in fact, must be on guard against excessive "squareness".
The next level concerns the entire structure of any single more or less self-contained musical piece. If the hymn, ballad, blues or dance alluded to above simply repeats the same musical material indefinitely then the piece is said to be in strophic form overall. If it repeats with distinct, sustained changes each time, for instance in setting, ornamentation or instrumentation, then the piece is a Theme and variations. If two distinctly different themes are alternated indefinitely, as in a song alternating verse and chorus or in the alternating slow and fast sections of the Hungarian czardas, then this gives rise to a simple twofold or binary form. If the theme is played (perhaps twice), then a new theme is introduced, the piece then closing with a return to the first theme, we have a simple ternary form. - (see Single forms below)
Great confusion, argument and misunderstanding can be generated by such terms as "ternary" and "binary", however, since a complex piece may have elements of both at different organisational levels. For example, a simple minuet, like any Baroque dance, generally had a simple AABB binary structure - but this was frequently extended by the introduction of another minuet arranged for solo instruments (called the trio), after which the first was repeated again and the piece ended. This, of course, is a ternary form - ABA: the piece is binary on the lower compositional level but ternary on the higher. Organisational levels are not clearly and universally defined in western musicology, while words like "section" and "passage" are used at different levels by different scholars whose definitions, anyway, as Scholes (1977) and others point out, cannot keep pace with the myriad innovations and variations devised by musicians.
The grandest level of organisation is sometimes called "cyclical form" (Scholes 1977): it concerns the arrangement of several more or less self-contained pieces into a large-scale composition. For example, a set of songs having a related theme may be presented as a song-cycle whereas a set of Baroque dances was presented as a suite. The opera and ballet may organise song and dance into even larger forms, perhaps based upon the layout of a Shakespearean drama. A setting of the Roman Catholic mass requires certain hymns in a certain order. This level of musical form, though it again applies and gives rise to different genres, takes more account of the methods of musical organisation used. For example a symphony, a concerto and a sonata differ in scale and aim but generally resemble one another in the manner of their organisation. The individual pieces that make up the larger form are sometimes called movements. (see Cyclical forms below)
Scholes (1977) suggested that European classical music had only six main stand-alone forms; simple binary, simple ternary, compound binary, rondo, air with variations, and fugue, although he allowed for several sub-categories and hybrids. Mann (1958), however, while confirming that the fugue has taken on certain structural conventions at times, emphasised that it is primarily a method of composition.
Where a piece cannot readily be broken down into sectional units (though it might borrow some form from a poem, story or programme) It is said to be through-composed. Such is often the case with pieces named Fantasia, Prelude, Rhapsody, Etude or study, Symphonic poem, Bagatelle (music), Impromptu, etc.
Keil (1966) classified forms and formal detail as sectional, developmental or variational.
Sectional form is built from a sequence of clear-cut units (DeLone 1975) that may be referred to by letters as outlined above but also often have generic names such as Introduction and Coda, Exposition, Development and Recapitulation, Verse, Chorus or Refrain and Bridge. Introductions and codas, when they are no more than that, are frequently excluded from formal analysis. All such units may typically be eight measures long. Sectional forms include:
- Strophic form (AAAA...) indefinitely - the "unrelieved repetition" that is one extreme of the spectrum of musical form.
- Medley, potpourri or Chain form: this is the opposite extreme of "unrelieved variation": it is simply an indefinite sequence of self-contained sections (ABCD...), sometimes with repeats (AABBCCDD...). Orchestral overtures, for example, are sometimes no more than a string of the best tunes of the show to come, possibly, like Johann Strauss' Blue Danube waltz, ending with a reprise of the main theme; ((intro)ABCD...A1(coda)).
- Binary form using two sections (AB...); each section is often repeated (AABB...). In 18th-century western classical music simple binary form was often used for dances and carried with it the convention that the two sections should be in different musical keys but maintain the same rhythm, duration and tone. The alternation of two tunes gives enough variety to permit a dance to be extended for as long as may be required.
- Ternary form, having three parts. In Western classical music a simple ternary form has a third section that is a recapitulation of the first (ABA). Often the first section is repeated (AABA) This approach was popular in the 18th-century operatic aria and was called da capo (i.e. "repeat from the top") form: later it gave rise to the 32-bar song, the B section then often being called the "middle eight". A song has more need than a dance of a self-contained form with a beginning and an end.
- Rondo form has a recurring theme alternating with different (usually contrasting) sections called episodes. It may be asymmetrical (ABACADAEA) or symmetrical (ABACABA). A recurring section, especially the main theme, is sometimes more thoroughly varied, or else one episode may be a development of it. A similar arrangement is the ritornello form of the baroque concerto grosso. Arch form (ABCBA) resembles a symmetrical rondo without intermediate repetitions of the main theme.
Variational forms are those in which variation is an important formative element.
- Theme and Variations: a theme, which in itself can be of any shorter form (binary, ternary, etc.), forms the only "section" and is repeated indefinitely (as in strophic form) but is varied each time (AA1A2A3A4A5A6), so as to make a sort of sectional chain form. An important variant of this, much used in 17th-century English music and in the Passacaglia and Chaconne, was that of the ground bass - a repeating bass theme or basso ostinato over and around which the rest of the structure unfolds, often, but not always, spinning polyphonic or contrapuntal threads, or improvising divisions and descants. This is said by Scholes (1977) to be the form par excellence of unaccompanied or accompanied solo instrumental music. The Rondo is often found with sections varied (AA1BA2CA3BA4) or (ABA1CA2B1A).
Developmental forms are built directly from smaller units, such as motifs, combined and worked out in different ways, perhaps having a symmetrical or arch-like underpinning and a progressive development from beginning to end. By far the most important in Western classical music is;
- Sonata form (also known as sonata allegro form, first movement form, compound binary, ternary and a variety of other names, all of which have been found wanting in one way or another (Scholes 1977). This developed from the binary-formed dance movement described above but is almost always cast in a greater ternary form having the nominal subdivisions of Exposition, Development and Recapitulation. Usually, but not always, the "A" parts (Exposition and Recapitulation, respectively) may be subdivided into two or three themes or theme groups which are taken asunder and recombined to form the "B" part (the Development) - thus e. g. (AabB[dev. of a and/or b]A1ab1+coda). This developmental form is generally confined to certain sections of the piece, as to the middle section of the first movement of a sonata, though nineteenth-century composers such as Berlioz, Liszt and Wagner made valiant efforts to derive large-scale works purely or mainly from the motif.
Chester (1970) distinguished this as Extensional music, that "produced by starting with small components - rhythmic or melodic motifs, perhaps - and then 'developing' these through techniques of modification and combination." Intensional music, meanwhile, "starts with a framework - a chord sequence, a melodic outline, a rhythmic pattern - and then extends itself by repeating the framework with perpetually varied inflections to the details filling it in." (Middleton 1999, p. 142).
Opera was originally modelled upon classical drama and takes much of its form from its libretto and narrative. Ballet was for many years a component of opera, not in itself narrative but having the form of a suite of set dances included at some appropriate moment in the story such as a festival or wedding. It emerged as a separate form, supplying its own narrative or representation, during the nineteenth century CE. At the same time the Song cycle emerged, a set of related songs as the suite is a set of related dances. The Oratorio took shape as a narrative, often religious, recounted but not acted by the singers.
The Sonata, Symphony and Concerto were all developed by the great composers of the Viennese school, Haydn, Mozart and Beethoven along the same formal lines into distinctively musical forms limited little by the forms of song, dance or ceremony. Other forms of music, such as the Catholic Mass and Requiem, are largely shaped by and subordinated to their texts and ceremonial functions.
More recent developments
A common idea is the "depth" of layers of form necessary for complexity, in which foregrounded "detail" events occur against a more structural background, as in Schenkerian analysis. Lerdahl (1992), among others, argues that popular music lacks the structural complexity of multiple structural layers and thus lacks depth. However, Lerdahl's theories explicitly exclude "associational" details which are used to help articulate form in popular music, which Allen Forte's book theories were designed to analyse. (Middleton 1999, p. 144).
Western classical music is the apodigm of the extensional form of musical construction. Theme and variations, counterpoint, tonality (as used in classical composition) are all devices that build diachronically and synchronically outwards from basic musical atoms. The complex is created by combination of the simple, which remains discrete and unchanged in the complex unity...If those critics who maintain the greater complexity of classical music specified that they had in mind this extensional development, they would be quite correct...Rock however follows, like many non-European musics, the path of intensional development. In this mode of construction the basic musical units (played/sung notes) are not combined through space and time as simple elements into complex structures. The simple entity is that constituted by the parameters of melody, harmony, and beat, while the complex is built up by modulation of the basic notes, and by inflexion of the basic beat. All existing genres and sub-types of the Afro-American tradition show various forms of combined intensional and extensional development.
—Chester 1970, p.78-9
Similarly, (Middleton 1999, p. 115) maintains that "syntactic music" is "centered" on notation and "the hierarchic organization of quasilinguistic elements and their putting together (com-position) in line with systems of norms, expectations, surprises, tensions and resolutions. The resulting aesthetic is one of 'embodied meaning.'" on the other hand, non-notated music and performance "foreground process and are concerned with gesture, physical feel, the immediate moment, improvisation; the resulting aesthetic is one of 'engendered feeling' and is unsuited to the application of 'syntactic' criteria".
Connection and contrast may be achieved in new ways. Procedures of connection include gradation, amalgamation, and dissolution. Procedures of contrast include stratification, juxtaposition, and interpolation.
Especially recently, more segmented approaches have been taken through the use of stratification, superimposition, juxtaposition, interpolation, and other interruptions and simultaneities. Examples include the postmodern "block" technique used by composers such as John Zorn, where rather than organic development one follows separate units in various combinations. These techniques may be used to create contrast to the point of disjointed chaotic textures, or, through repetition and return and transitional procedures such as dissolution, amalgamation, and gradation, may create connectedness and unity. Composers have also made more use of open forms such as produced by aleatoric devices and other chance procedures, improvisation, and some processes. (ibid)
Forms of chamber music are defined by instrumentation (string quartet, piano quintet and so on). The structure of a chamber work is typically similar to a sonata.
- Lerdahl, Fred (1992). "Cognitive Constraints on Compositional Systems", Contemporary Music Review 6 (2), pp. 97–121.
- Macpherson, Stewart (1930). "Form". Form in Music (New and Revised ed.). London: Joseph Williams.
- Mann, Alfred (1958). The Study of Fugue, W.W.Norton and Co. Inc.
- Middleton, Richard (1999). "Form". in Horner, Bruce; Swiss, Thomas. Key Terms in Popular Music and Culture. Malden, Massachusetts: Blackwell Publishing. ISBN 0-631-21263-9. http://books.google.com/books?id=gY-w68zIQWQC.
- Scholes, Percy A. (1977). "Form". The Oxford Companion to Music (10th ed.). Oxford University Press.
- Wennerstrom, Mary (1975). "Form in Twentieth Century Music". Aspects of Twentieth-Century Music. Englewood Cliffs, New Jersey: Prentice-Hall. ISBN 0-13-049346-5.