Many historians, theorists, and teachers consider one form in particular to be the premier compositional structure of tonal Western art music. Sonata form, as it is commonly known, emerged as one of the most popular thematic/harmonic designs during the Classical and Romantic eras. It is found in nearly every type of composition—not just solo sonatas, but works for chamber groups and orchestras as well. And although it grew out of instrumental traditions, elements of sonata form may even be found in vocal music from this period. In fact, the form had such sweeping influence that we might even go so far as to think of it as a style instead of just an organizational framework for melodies and keys.
For reasons that will become clear momentarily, we will begin this chapter with an abstract overview of the sonata form design. We will then trace the form through three separate works—the first two will be relatively straightforward, whereas the third will demonstrate some of the playful alterations that composers tend to make when writing in sonata form. Our discussion will conclude with a brief overview of several common variations.
Note: Some texts and teachers refer to sonata form as first movement form, since it is frequently found in the first movement of a multi-movement sonata. Others use the term sonata allegro form since these opening movements are typically set at a relatively rapid tempo. Neither of these terms is completely accurate, though, since the form may be found beyond the first movement and in slower tempos as well. Given that the form is frequently found in works outside the solo sonata genre, one might even argue that the term sonata form itself is misleading. Nonetheless, the term is widely used and we will use it here.
Due in part to the wide variety of locations in which it may be found, sonata form as a whole tends to exhibit much more flexibility than the other forms discussed in this book. Whereas straightforward examples of binary, ternary, and rondo forms are plentiful, most instances of sonata form tend to have some unique or quirky qualities. It would be misleading, then, to point to a singular thematic/harmonic design as universal. Instead, we will highlight some general characteristics that are common to many sonata forms and, in doing so, describe a kind of idealized model. The analyses that follow will illuminate a few of the many ways composers tend to adjust and reconfigure this model.
Generally speaking, a sonata form may be thought of as an expansion of a continuous rounded binary, the form of which (as discussed in Chapter 36) is shown in the following diagram:
Like a continuous rounded binary, the first large-scale section of a sonata form accomplishes two things: first, it presents the main thematic material of the piece, and second, it modulates away from the home key. The second section then begins with some contrasting material in the secondary key. Finally, the opening material returns in the home key to end the piece. This time, however, it is adjusted, recomposed to avoid the modulation that led away from the tonic in the first place.
In a binary form, the difference in character between the A and B sections is relatively subdued. In a sonata form, the B section plays a much more substantial role. In fact, in many later works written in sonata form, the B section is much longer than would ever be found in a rounded binary. It is dramatic and exciting, and for many listeners it is the highlight of the composition. In this sense, the B section of a sonata form is more like the B section of a ternary form. Sonata form overall, then, is best thought of as a hybrid of the two: it takes the basic thematic/harmonic structure of continuous rounded binary form and combines it with the characteristic contrast of ternary form. In other words, a sonata form has a three-part thematic organization superimposed over a two-part tonal plan.
The three parts of a sonata form—corresponding with the A, B, and A′ of a rounded binary—tend to be much longer and more substantial than any of the large-scale formal sections we’ve seen so far and as such, they are given special names. The A section is called the exposition when it is heard at the beginning and the recapitulation when it comes back at the end. The intervening B section is called the development. The following diagram replaces the letter labels of Example 38–1 with these names:
Each of these three sections plays a crucial role in a sonata form. One introduces musical ideas, one provides contrast, and one brings the opening ideas back in a transformed state. And just as we may talk about the place and purpose of each of these sections in the form overall, we may also examine their internal structures and describe what a listener might expect to hear and experience from each.
The exposition section of a sonata form presents the main thematic material as well as the complementary key areas in which the themes are presented. In its most essential form, the exposition will consist of one theme in the home key and a different theme in a secondary key with a transitional passage in between. The most common secondary keys in a sonata form are the same as those seen in continuous binary forms: if the piece begins in a major key it will most likely modulate to the dominant; if it begins in a minor key it will most likely modulate to the relative major or minor dominant. Within this basic framework, though, there is quite a bit of flexibility.
Most expositions begin directly with the primary theme area, the first melody or melodies heard in the piece, presented in the home key. (In some cases, though, a sonata form may begin with a brief introduction—a passage designed to prepare the listener for the arrival of the primary theme.) The listener is expected to remember the opening melodic material, and so composers typically present it in a clear and tonally unambiguous manner. The primary theme area is therefore frequently presented in a recognizable standard form such as a sentence, period, or double period.
The primary theme typically concludes in a clear cadence, after which the transition begins. The role of this section is to depart from the primary theme area. A typical transition may feature scalar passages, sequences, and various musical elements designed to disorient the listener. Elements of the primary theme area may be present, but if so tend to be fragmentary and disintegrating as the piece moves away from its origin.
An important musical event is found marking the end of most transitions: the medial caesura. The term “caesura” refers to a rest or break in the music and indeed the transition section is often followed by a short pause, sometimes drawn out with a fermata. The word “medial,” in this case, indicates that the event typically occurs close to the middle of the exposition. In some cases, the music continues through the medial caesura without stopping. When this happens, the listener will likely still have a strong sense that the departing trajectory of the transition has halted abruptly. Almost invariably, the medial caesura is marked by a dramatic half cadence setting up for the arrival of the next important melody.
Note: The modulation to the secondary key may or may not actually take place in the transition. If it does, the medial caesura will occur with a half cadence in the secondary key—ending, in other words, on a dominant function, the implied resolution of which is the tonic of the new key. If the transition does not modulate, the medial caesura will coincide with a half cadence in the home key, after which the following material reinterprets the home-key V chord as the new tonic. More importantly, the transition section will almost always destabilize the home key and prepare the listener for the new key, regardless of whether or not the modulation takes place within or without.
The secondary theme area follows immediately after the medial caesura. Here, the listener is presented with a new melody. This melody typically has a contrasting character when compared to the thematic material heard at the beginning. In many sonatas, the primary theme has a bold or aggressive nature while the secondary theme is comparatively sweet or lyrical. These characterizations are far from standard, though, and should not necessarily be taken as the norm. More importantly, the new melody is set in the secondary key (again, the dominant or relative major).
Note: You may occasionally encounter a sonata form in which the secondary theme is simply a transposition of the primary theme to the new key. Such pieces are said to be in a mono-thematic sonata form.
The word “area” is more appropriate here because, unlike the primary theme area, which typically includes just a single theme, the secondary theme area frequently features multiple distinct melodic ideas. Some texts and teachers use the term secondary theme group for this very reason. One of the more common inclusions in this group is a closing theme, a short melody heard at or near the end of the exposition that projects a sense of conclusiveness. Just as an exposition may begin with an introduction, it may also end with a brief passage—usually just two to four bars—called a codetta which reasserts the secondary key with one or more clear PACs. In most sonata forms, the entire exposition then repeats before proceeding on to the development.
Note: More so than with other formal paradigms, the terminology used to describe sonata forms is inconsistent from one text or teacher to another. The following table displays some of the semi-synonymous terms used to describe various parts of the exposition:
|Primary theme area:||Secondary theme area:||Closing section:|
first tonal area
first theme group
second tonal area
second theme group
The following diagram summarizes the structure of a typical exposition:
The development section typically begins where the exposition left off, in the secondary key. In some cases, a composer may take the primary theme and transpose it to the new key, giving the listener the sense that they have returned to the beginning once more. This sense does not last long, however, as development sections typically waste little time in revealing their true function and nature.
Unlike the exposition, which, aside from the transition section, is harmonically stable and clearly organized, the typical development is chaotic. In some cases, the listener will recognize elements of melodies heard earlier in the piece. When this happens, though, the melodies are not exactly the same as when they were first heard. They are instead—as the name of the section implies—developed. The themes from the exposition may be transposed, fragmented, rearranged, combined in new ways, or otherwise altered and transformed. The listener may also hear entirely new material in the development section. Like the transition section from the exposition, a development section may also include passages of scales and sequences. The effect of all this can be very exciting, a peculiar experience in which moments of clarity emerge from an otherwise dizzying musical landscape.
Aside from working out various figures and melodies heard earlier in the piece—and occasionally presenting new thematic ideas—the other function of the development is to prepare the listener for the recapitulation. Harmonically, a development section may move through several keys before leading back to the home key. To rein in this harmonic instability, most development sections end with a retransition, typically written as a prolonged V or V7 chord in the home key. The intention here is to get the listener to expect a resolution to the home key tonic and in doing so set up for the return of the primary theme area.
The recapitulation is essentially a repeat of the exposition with one crucial difference. Whereas the exposition begins and ends in different keys, the recapitulation must omit the modulation in order to avoid ending the piece in the wrong key. Most recapitulations will therefore recompose one or more sections of the exposition.
In a typical sonata form, the initial modulation to the secondary key takes place in the transition section of the exposition. It is in the corresponding section of the recapitulation, then, that the recomposition usually takes place. In most cases, the various melodic elements that made up the transition in the first place will still be present. The listener, in other words, will still recognize this passage as a transition. But in the recapitulation these elements may be transposed or otherwise altered to avoid modulating. A composer may employ any one of a number of strategies to accomplish this task, but in almost all cases the transition section of the recapitulation will conclude with a medial caesura that sets up the secondary theme or themes to be presented in the home key.
Everything from the exposition that was originally presented in the secondary key—the themes, the closing, the codetta—will here be transposed to the opening tonality, thereby combining the thematic closure of the exposition with the harmonic closure of the home key and reconciling the thematic/harmonic conflict established by the exposition.
The following diagram summarizes the structure of the development and recapitulation in a typical exposition:
Many authors writing about sonata form describe it in terms of a dramatic narrative. At its heart, this narrative—like so many fictional and historical stories—is one of conflict and resolution. In musical terms, the conflict is manifest in the juxtaposition of different melodies set in opposing keys. Following the initial presentation of these melodies and their respective tonalities (the exposition), the form proceeds through a tumultuous period in which the conflict is complicated by the reworking of previously heard ideas and the introduction of new elements (the development). The form concludes with a dramatic resolution when the conflicting melodies are both united in a single key (the recapitulation).
Now that we have discussed the general structure of a sonata form, let us look at several examples. The first two will be relatively straightforward; the third will present some complications. As you listen to each example, keep track of the basic formal elements discussed above. Identifying cadences as you hear them—their key and their type—will be particularly helpful. But also consider the character and nature of each section as you listen to it. When listening to a sonata form, you will very likely encounter passages that are:
- introductory, preparing the listener for music that is more structurally significant,
- expository, presenting thematic material with clarity in a harmonically stable context,
- transitional, loosening the grasp of a key or theme and moving toward something new (often using sequences and other busy-sounding figuration),
- developmental, taking previously heard material and presenting it in new ways (typically in a harmonically unstable context), and
- terminative, signaling to the listener that an important ending point is coming up through the use of repetitive, conclusive sounding cadences.
Just as a chord may perform a particular function within a phrase, so too may a section of music perform a particular function in building a larger form. At each new turning point, ask yourself, “What is this passage trying to communicate or accomplish?” This mode of listening will help illuminate the way each section contributes to the overall form.
The following piece is in sonata form, and the various sections have been labeled.
As in most sonata forms, the boundaries of this exposition are clearly identifiable thanks to the double barline and repeat symbol at the end of m. 43. The primary theme in this exposition is a sentence, heard first in mm. 1–8:
The harmonic setting is stable and unambiguous, giving the listener a solid sense of the key: Eb major. The theme itself is clear and easy to remember. It ends with a half cadence in m. 8 and then again in m. 16 when the sentence repeats.
Notice, however, that in the second half cadence the embellishing notes around the Bb in the upper staff include an A§. As a listener, it is safe to assume that because this piece begins in a major key it will modulate to the dominant—in this case, Bb major, which will need A§s to cancel out the third flat in the key signature. This A§, then, is the first indication that the piece is moving away from the stability of the primary theme area and into the transition.
The new material in m. 17 confirms this suspicion. The left hand switches to a more energetic triplet rhythm while the right hand plays figures that are sequenced first up (mm. 17–20) and then down (mm. 21–23). These types of patterns are the hallmarks of a transition section and, as the now consistent A§s confirm, that is exactly where we are in the exposition. These elements project a strong sense of motion toward something new, inviting the listener to keep on the lookout out for a clear indication of where the passage will lead.
The expected signal turns out to be a prolonged F-major chord in mm. 24–28. When a minor seventh (Eb) is added to a clear arpeggiation of the chord in m. 28, the listener will hear it as the dominant seventh, a half cadence in the key of Bb major. This is the medial caesura. Although the music does not stop, there is still a clear halting of the harmonic motion heard earlier in the transition. The F dominant seventh clearly implies a resolution to Bb and that is exactly what happens next.
The secondary theme area begins with a new melody in Bb major (m. 29). The melody is not entirely unrelated to the primary theme, but is distinct enough to identify it as something new. Whereas the primary theme area consisted of a repeated sentence, the main melodic material of the secondary theme area consists of a parallel period—the antecedent ends with a HC in m. 32 and the consequent with a PAC four bars later. The remainder of the exposition presents a series of conclusive PACs in Bb major, confirming the move to the new key. We may call the material in mm. 36–41 a closing theme and mm. 42-43 a codetta.
Note: Note the trilled scale degree 2 leading to a PAC in m. 41. As we will see in the following analyses, this particular figure is often used to signal a particularly important structural cadence.
The development begins after the exposition repeats. In this case, we hear quite a bit of the opening material coming back in new and interesting ways. The triplets, for example, are reminiscent of the transition section heard after the primary theme area. (This is appropriate since, like the transition section itself, one of the functions of the development is to transition back to the original key area.) In m. 60 we find a passage that is again reminiscent of the transition. Compare mm. 60–64 with mm. 24–28. They are nearly identical, though here it is a G-major chord that is being prolonged. Since the F-major prolongation led to the secondary theme in the key of Bb major, the listener might expect to hear the secondary theme in C major next. Instead, we are presented with the second half of the primary theme, but now in the relative key of C minor! False leads such as this and other surprises are to be expected in a typical development section.
The retransition begins in m. 72, immediately following the passage in C minor. At this point in the development section the listener may have given up on trying to figure out where things are going! We first hear the V7 of the home key in m. 73, but coming after a cadence in C minor the listener will likely hear it as VII7 or V7/III. The following measures clear things up a bit. Several repetitions of this same chord resolving to Eb-major, indicate that we have returned to the home key. The big HC in m. 84 sets up the recapitulation in much the same way that the HC in m. 28 set up the secondary theme.
The following example shows the retransition and the first measure of the recapitulation:
The recapitulation proceeds as expected with some minor adjustments. Here, for example, we hear only the first eight bars of primary theme area. The repetition of the sentence—the phrase that originally introduced the A§s (mm. 9–16)—has here been omitted since the recapitulation does not need to modulate. The transition section also returns more or less intact, but with one very important change. Here in the recapitulation it has been transposed down a perfect fifth (compare m. 93 to m. 17). The transposed transition now leads to a half cadence in Eb major instead of Bb major. Everything that follows matches the secondary theme area of the exposition, but now in the home key.
The following piece presents another clear example of sonata form:
The primary theme in this sonata form is a double period. Phrases ending in an IAC (m. 4) and a HC (m. 8) make up the antecedent and phrases ending in an IAC (m. 12) and a PAC (m. 16) make up the consequent. The transition section begins on an elided cadence, a phrase overlap in which the concluding tonic of one phrase also serves as the beginning of the next phrase. Again, the transition section is marked not only by a cadence ending the opening section but also by a shift in figuration. In this case, the octave scales in mm. 16–19 are designed to alert the listener that the piece is moving in a new direction.
Since this piece begins in major, we can expect it to modulate to the dominant somewhere before the secondary theme area. Since the dominant of C major is G major, the telltale accidental will be an F#. Sure enough, the F§s consistently become F#s starting in m. 21. To the listener expecting a half cadence in the new key, the arpeggiated dominant seventh chord in m. 28 sounds a lot like a medial caesura—compare this moment to m. 28 in Example 38–5—and the melody that follows sounds a lot like a secondary theme.
The new theme in m. 30 seems to fit all of the requirements for the secondary theme: it is in G major, it appears after a pronounced half cadence in the new key, and its lyrical character provides contrast to the comparatively brash primary theme. The only problem is that it does not last. After just four bars we find another large half cadence: a highly unstable V7 chord in third inversion marked by a fermata and followed by rests in both staves. This is the true medial caesura—the arpeggiated dominant in m. 28 was a ruse! As mentioned at the beginning of this chapter, sonata form was exceptionally popular during the common practice era. We may understand moments such as these, then, as composers having a bit of fun, playing with the expectations of an informed listener.
In this piece, the secondary theme area (beginning with the pickup to m. 34) is comprised of a series of short, distinct thematic ideas as opposed to a single, more substantial melody. We hear a set of three four-bar phrases—mm. 34–37, mm. 38–41, and mm. 42–45—each ending with a clear G-major harmony. Cases such as this are why some analysts use the term second theme group. Beginning in m. 45, a series of scales reaffirms the move to G major. Note again the prolonged trill on 2 in m. 51 signaling the most conclusive cadence in the secondary theme area. As was the case with Example 38–5, we may hear the terminative passage that follows this cadence as a closing theme (mm. 53–60) with a codetta in mm. 60–64 rounding out the exposition.
The development in this sonata begins with material that is reminiscent of the secondary theme area but distinct enough that it may be heard as a new melody—compare, for example, mm. 65–68 with mm. 34–37. When this ends in m. 76, we find the same octave scales that began the transition. In this case, though, they end on G# and lead to a new melody in A minor, the relative minor of the home key (mm. 78–84). After a pronounced half cadence in m. 84, we hear what sounds at first like another theme in A minor but turns out to be the retransition, pivoting back to C major in m. 89:
Only minor alterations are made in the recapitulation, mostly in the form of omissions. In the primary theme area, for example, we hear only the second half of the double period that opened the piece. The transition section is much shorter, too, consisting of only the false secondary theme from m. 30, here transposed to lead to a medial caesura in the home key. The first eight bars of the secondary theme area are cut entirely in the recapitulation, but the material from mm. 42 to the end of the exposition remains intact and is, as expected, united with the primary theme in the home key.
Our third analytical example of sonata form is taken from a harp sonata and incorporates several features that may surprise a listener familiar with the type of thematic/harmonic structures discussed above:
The following questions pertain to the sonata form shown in Example 38–10.
In what key does this sonata form begin?
Note the lack of sharps and flats in the key signature and the authentic cadence in m. 9.
In what measure does the primary theme area end and the transition begin?
Listen for a change in character in which the clear presentation of a melody shifts to arpeggios and passagework.
In which key does the exposition conclude? And is this the expected secondary key?
Sonata forms in major keys almost always modulate to their respective dominants.
G major and yes.
Through which keys does the development pass?
Listen for the standout cadences: HC in m. 53 (note the accidentals in the melody that follows), HC in m. 74, HC in m. 83.
G major to G minor to Bb major to C major.
In what key does the piece conclude?
Sonata forms almost invariably end with material from the end of the exposition transposed to the home key.
One of the most surprising features of this sonata form is the repeated delay of the secondary theme area. Following a pair of parallel phrases in the primary theme area, the transition begins in m. 17. Since this piece begins in C major, we may expect to find F#s indicating a move to the dominant. We find the first of these in m. 18, but in m. 20 find it has reverted back to to F§.
The next F#, at the end of m. 23, tonicizes the half cadence in m. 24. This may at first seem like the medial caesura. It is even followed by a new theme. But this melody is still in the home key and so must be considered a part of the transition. The cadence in m. 24 was not the medial caesura, but instead was a misdirection. Another tonicized half cadence appears in m. 33. The listener might wonder if this is the medial caesura. But once again, the F§ in the melody that follows confirms that we have not yet fully departed from the home key.
F#s appear once again beginning in m. 36, and this time they are here to stay. When the listener hears the prolonged arpeggiation of a D-dominant-seventh chord in m. 39, they might wonder if this is the true medial caesura or if it is just another trick. A fermata at the end of the measure helps confirm that this is finally the end of the transition. At this point, however, the end of the exposition is near and the secondary theme area consists of just a short G-major melody in octaves ending with a conclusive PAC in the secondary key, a closing theme to complete the exposition. The effect is as though time has run out and skipping over the secondary theme was done out of necessity, or perhaps that the melodies that should have been played in G major were accidentally put in the home key. Regardless, the way the exposition unfolds in this piece seems almost like a parody. This kind of playful self-awareness, however, is common in sonata forms. It happens so frequently that it may be better understood as characteristic of the form and not just as an occasional anomaly.
The development section begins in G major and passes through several surprising keys on its way back to the tonic. A half cadence in m. 53, for example, leads to a passage in G minor—the parallel minor of the dominant key. This passage features a new theme, first in octaves on the upper staff (mm. 54–61) and then on the lower (beginning in m. 64). A sequence in mm. 71–73 leads to another cadence, just like the one in m. 53 but here consisting of three F-major chords. Although coming after the sequence it may not be heard as such, it soon becomes clear that this is another half cadence. It leads to a familiar melody (compare m. 75 with the first false secondary theme in m. 24), but now presented in Bb major, the key of the subtonic. As is often the case, this development section balances new material and new keys with old material presented in new ways.
The development retransitions back to the home key by tonicizing the ii (C minor) chord in Bb major. When the third V/ii resolves to a C major chord it is the beginning of the primary theme in the recapitulation:
The recapitulation in this sonata form is much shorter than the exposition. The primary theme in mm. 84–88 matches the first five measures of the piece, but then begins to diverge. The transition section is dramatically reduced here, omitting all of the false medial caesuras and teaser themes, although the trilled 2 in m. 93 gives the impression of arriving at the end before it actually happens. The transposed closing theme appears after the fermata in m. 97 and closes the piece in the home key.
38.4 Other forms
As we have now seen, composers writing in sonata form are fond of mixing things up and playing with their listeners’ expectations. In some cases, these tricks and variations are common enough to warrant names. Composers will sometimes include, for example, a false recapitulation. In such pieces, the listener will hear an instance of the primary theme in the midst of the development, but rather than starting the recapitulation, it will lead instead to more developmental material. In other cases, the development may lead to a subdominant return, a recapitulation in which the entire exposition appears intact but transposed down a perfect fifth. With the recapitulation starting in the key of the subdominant, the modulation that led up a fifth to the dominant in the exposition will instead lead up a fifth to the home key, the proper harmonic goal at the end of the piece. As you listen to and analyze sonata forms you should keep in mind that the form is flexible, and twists like these make it appealing to composers and listeners alike.
Some alterations to sonata form are substantial enough that we may think of them as creating an entirely new form. One example of this may be found when a sonata form is set at a slower tempo: in a sonatina or slow-movement form, the development section is greatly reduced or omitted altogether. After the repeat of the exposition, the listener hears a brief retransition followed immediately by the recapitulation—or, where the development is omitted, just the recapitulation:
Note: In the interest of conserving space we will not include examples of the forms discussed in this section. Readers are advised to analyze the following pieces to see sonatina form in action:
- Wolfgang Amadeus Mozart, Piano Sonata No.3 in Bb major (K.281/189f), II. Andante amoroso
- Marianne Auenbrugger, Keyboard Sonata in Eb major, II. Largo
In each of these two movements, the second large-scale section features a brief retransition leading directly into the recapitulation. Neither has a substantial development.
Some sonata forms incorporate elements of other forms. A sonata rondo, for example, combines sonata form with the seven-part rondo (see Chapter 37). The form is very similar to a regular sonata form, but includes a repeat of the primary theme area at the end of the exposition and again at the end of the recapitulation. If the form is mapped out as ABACABA, the A sections and B sections represent, respectively, the primary and secondary theme area. A and B combined, then, form the exposition and C the development.
The following diagram provides an overview of sonata rondo form. Notice that the primary theme area (A) is typically set in the home key in each of its four appearances. This is a rather significant departure from sonata form as described above, where the exposition ends in the secondary key and leads directly into the development:
The primary characteristic that distinguishes a sonata rondo from a regular seven-part rondo is the development section. For a rondo to be considered a sonata rondo, the C section must incorporate developmental passages in the manner found in a typical sonata.
Note: Examples of sonata rondo form may be found in:
- Wolfgang Amadeus Mozart, Piano Sonata No. 13 in Bb major (K.333/315c), III. Allegretto grazioso
- Ludwig van Beethoven, Piano Sonata No. 8 in C minor [Pathétique] (Op. 13), III. Rondo. Allegro
As mentioned above, sonata forms routinely appear in symphonic works as well including a variant typically found in the first movement of a concerto, where a soloist is accompanied by an orchestra. In concerto form, the soloist plays through all three of the main sections—exposition, development, recapitulation—in order. (The solo sections are labeled with an “S” in the diagram below.) Alternating with these sections, however, are passages in which the musical focus is on the orchestra. (In the diagram below, the orchestral sections are labeled with a “T” for tutti, the Italian word for “all” or “together.”)
A concerto form begins with the full orchestra playing through the primary theme area in the primary key. They may play through the transition and secondary theme area, too, but if they do they will stay in the home key. The main action in a concerto form—including, for example, the modulation to the secondary key—is reserved for the soloist, who plays through the exposition again in S1. (Some teachers and texts prefer the term double exposition form over concerto form for exactly this reason.) At the end of the soloist’s exposition, the orchestra typically comes back (T2) and plays a short passage, often featuring a brief melody, before the soloist launches into the development (S2). It is important to note that during the solo sections, the orchestra does not sit quietly. It plays behind the soloist, providing the supporting harmonies and musical punctuations. When the soloist reaches the end of the development, the orchestra may return once again (T3), but more often than not the soloist’s retransition will lead directly into the recapitulation (S3). At the end of the recapitulation, just before the final structural cadence, most concerto forms will include a cadenza, in which the soloist, unaccompanied, will play through or improvise an extended passage full of virtuosic figuration. The cadenza typically concludes with a trill, a signal to the conductor to cue the orchestra, and the piece concludes with the full orchestra playing once again (T4).
Note: For an example of concerto form, the reader is directed to Wolfgang Amadeus Mozart’s Piano Concerto in Eb major (K.107.3). This piece is particularly instructive since it takes as its basis the sonata written by Johann Christian Bach discussed in Example 38–5 above. In other words, the three main sections of Bach’s sonata—the exposition, the development, and the recapitulation—are found in the S1, S2, and S3 sections of Mozart’s concerto. The T sections use material from the same source.
Sonata form is often considered one of the premier thematic/harmonic structures of the common practice era and its influence may be found extending to most Classical and Romantic styles and genres. The form may be thought of as an extended continuous rounded binary, but with its substantial and contrasting middle section it also bears a meaningful resemblance to ternary form. Descriptions of sonata form typically go into much more detail than just the number and harmonic structure of the large-scale sections, but due to the remarkable variety found between pieces exhibiting sonata-form qualities, it is difficult to pin down a definitive and universal model. Instead, we describe some of the most commonly encountered general characteristics.
The first part of a sonata form, known as the exposition, typically presents contrasting thematic material divided between two conflicting keys—most often the home key and the dominant or relative major. In most sonata forms, the primary theme area is heard first, followed by a transition, and then, after an abrupt break in the musical texture called the medial caesura, the secondary theme area. Some sonata forms present a single theme in each theme area, but many others feature multiple themes per area, particularly the second which often includes a closing theme to conclude the exposition. Some expositions include introductions and codettas as well. The exposition is typically repeated.
The second part of a sonata form is the development, a lengthy section in which material from the exposition is reworked in new and exciting ways. Some developments present new thematic material as well and in some cases do not incorporate old material at all. The effect of a development section, with characteristic sequences and surprising changes of key, can be very exciting and for some composers, performers, and listeners it is the highlight of the form. The development section usually concludes with a retransition leading back to the original key for the recapitulation, a replaying of all of the main thematic material from the exposition, though here recomposed to avoid modulating to the secondary key.
More so than with the other formal designs discussed in this book, composers of sonata forms are often found defying or otherwise playing with expectations related to the listener’s presumed familiarity with standard thematic/harmonic structures. Misleading cadences and false themes are common and add to the overall excitement of a piece. Along similar lines, we find several common variants of the form including sonata forms which lack a development (sonatina or first-movement form), incorporate the repeated refrain of a rondo (sonata-rondo form), and assign the main sections to a soloist between passages played by a full orchestra (concerto or double-exposition form).