Sonata form
Sonata form or sonata-allegro form is a musical form, a way of organising the various themes within a piece. It has been very widely used by classical composers since the 18th century. It was the standard form for the first movement of a symphony, concerto, sonata or other works based on them, like string quartets. For this reason, it is sometimes called first movement form, although this is somewhat of a misnomer, as it has been used in other movements of pieces. It is also sometimes known as compound binary form.
The classical sonata form movement in its simplest version consists of the following sections:
Theorists have long sought to understand why the arrangements of keys and
themes used in sonata form have held such importance for classical composers
and their listeners. One influential view is that of Charles Rosen, who
conceives the sonata form movement as a kind of dramatic journey through the
system of musical keys. Modulations that move upward in the circle of fifths (in the direction of the sharp keys) increase musical tension, and
modulations that move downward reduce it. Sonata form first increases
tension through the move to the dominant (the crucial musical event of the
exposition), then increases tension further in the development through the
exploration of remote keys. The recapitulation resolves all this tension by
returning everything to the tonic.
The use of the circle of fifths makes sense of a number of observations about
the deployment of keys in sonata form:
The classical sonata form may be varied in a number of ways.
Occasionally the material of introduction reappears (in its original tempo)
later in the movement. Often, this occurs in the coda, as in Mozart's string
quintet K. 593, the Drumroll Symphony, or Beethoven's Pathetique piano
sonata Op. 13.
The monothematic exposition illustrates a general point made by Rosen about
the Classical sonata form: the crucial element of the exposition is that the
move to the dominant be dramatized in some way. Using a new theme was a
very common way to achieve this effect, but other resources (changes in
texture, salient cadences, etc.) were also available.
It is a open question why Beethoven never modulated just two fifths higher, a
major second; possibly this is because it might be perceived as a crude
stepwise modulation. (For a modern criticism of such modulations, see the
discussion of the "truck driver's gear change" in Modulation (music).)
Beethoven ultimately abandoned the three-key principle, as he came to adopt a tighter conception of sonata form.
In the Romantic era, modulation and use of remote keys extended beyond the
norms of the Classical period. This was, in a certain sense, an appropriate
time to abandon sonata form. Classical sonatas required a certain sense of
key stability in order to define a musical journey among keys, with the
contours of increased, then resolved, tension outlined above. When the use
of modulation became freer and more coloristic in purpose, it was no longer
possible to use the sequence of keys as an element of drama.
However, the work of the Classical era, especially
that of Beethoven, was very prestigious among the composers of the nineteenth
century, and they commonly felt that ability to write a sonata was a mark of
depth and significance in a composer's work. Sonata form thus became a
conventionalized method for creating a large scale work. As such, it was
often surprisingly successful, for instance in the work of Robert Schumann, Frederic Chopin, and Felix Mendelssohn.
Sonata form was an especially congenial mold for Johannes Brahms, who as a second-generation Romantic composer felt a strong affinity with the composers of the Classical era. Brahms adopted and extended Beethoven's practice of modulating to more remote keys in the exposition. For example, his piano quintet has the first subject in F minor, but the second subject in C sharp minor, a tritone higher. In the same work, the keys of the recapitulation is also altered - the second subject in the recapitulation is in F sharp minor, rather than the F minor of the first subject.
The first movements of several symphonies by Gustav Mahler, in the late
Romantic era, are described as being in sonata form, although they diverge
from the above scheme quite dramatically.
Sonata form shares characteristics with both binary form and ternary form. It terms of key relationships, it is very like binary form, with a
first half moving from the home key to the dominant and the second half
moving back again (this is why sonata form is sometimes known as compound binary form); in other ways it is very like ternary form, being divided
into three sections, the first (exposition) of a particular character, the
second (development) in contrast to it, the third section (recapitulation)
the same as the first.Outline of sonata form
(It should be noted that the above terminology is not universally used: some writers speak of the first and second subjects rather than groups, others speak of the pricipal or main theme and the subordinate theme.)The function of sonata form
Variation in sonata form
Codas
Quite often, a sonata form movement includes an additional section, the coda, which follows the end of the recapitulation. The coda rounds the movement off with a perfect cadence in the home key. Codas may be quite brief tailpieces, or they may be so lengthy as to be almost another development section.Introductions
Less often, the entire movement is preceded by a slow introduction. The
introduction increases the weight of the movement, and also permits the
composer to begin the exposition with a theme that would be too light
to start on its own, as in Haydn's Drumroll Symphony. Usually, but not always, the introduction is excluded from the exposition repeat.Monothematic expositions
It is not necessarily that case that the move to the dominant key in the
exposition is marked by a new theme. Haydn in particular was fond of
simply repeating the opening theme, often in a truncated or otherwise altered
form. Mozart, despite his prodigious ability to create melody, also occasionally wrote such expositions, for instance in the piano sonata K. 570 or the string quintet K. 593. Such expositions are often called monothematic. This term is usually
a misnomer when applied to a sonata form movement, since "monothematic"
expositions often include other themes later on in the second subject group.
Only on occasion (for example, in Haydn's string quartet Op. 50 no. 1) did
composers perform the tour de force of writing a complete sonata exposition with just one theme.Modulation to keys other than the dominant
The key of the second subject may be something other than the dominant or the
relative major. About halfway through his career, Ludwig van Beethoven
began to experiment with new keys for the second subject group. These keys
likewise move upward along the circle of fifths, but three or four fifths
instead of just one. Thus,the second subject of the Waldstein sonata for piano is in E major, fourth fifths higher (C --> G --> D --> A --> E) than the tonic key of C. The Hammerklavier sonata Op. 106 moves three fifths higher (Bb --> F --> C --> G). Modulations within the first subject group
The first subject group need not be entirely in the tonic key. In the more
complex sonata expositions there can be brief modulations to fairly remote
keys, followed by reassertion of the tonic. A vivid example is Mozart's
String quintet in C, K. 515, which visits c minor, Db major, and D major
before finally moving to the dominant of G major.The three-key exposition
In the early part of Beethoven's career, he favored for his grander works a
kind of exposition in which the exposition dwells on a third key before
finally moving to the dominant. For example, in the early major-key piano
sonatas this intermediate key is the dominant minor (Op. 2, no. 2), the
supertonic minor (Op. 2, no. 3), and the relative minor (Op. 10, no. 3).
Later, Beethoven used the supertonic major (Op. 14, no. 1, Op. 22), which is
only a mild sort of three-key exposition, since the supertonic major is simply is the dominant of the dominant, and commonly arises in any event as part of modulation. Sonata form in the postclassical era
Sonata form and other musical forms
