III. Form

Expansion and Contraction at the Phrase Level

John Peterson

Key Takeaways

  • make a phrase last longer than expected. They can be internal (between the beginning and ending of the phrase) or external (before the beginning or after the end).
    • Internal expansion techniques include: , , , and .
    • External expansions include:
      • : occur before the beginning, such as an introduction
      • : occur after the cadence, such as , , and .
  • make a phrase shorter than expected.


Chapter Playlist

The terms and refer to ways composers play with the expected length of a phrase.

What does “expected length” mean?

  • When a invokes one of the , we can often predict how long the phrase/subphrase might have been had it been a closer representation of the archetype
  • Sometimes the cadential motion of the phrase allows us to anticipate where a cadence might occur, but the phrase the expected cadence.
  • Sometimes a piece states two versions of a phrase—one unexpanded and the other expanded—giving us a model to which we can compare the expanded version.

Expansion refers to the process of making a phrase longer than we expect. This lengthening might occur within the phrase (““) or outside of the phrase (““). Contraction refers to the process of making a phrase shorter than we expect. It always occurs within a phrase.

In this chapter we offer an overview of several techniques of phrase expansion and contraction. This isn’t an exhaustive list, but it covers several of the more common techniques. The terminology concerning expansion and contraction techniques can quickly become overwhelming. What’s most important is to be able to recognize when a phrase is longer or shorter than expected and to be able to describe what’s creating the additional length.

Internal Expansions

The four techniques we discuss below—, , , and —all occur within a phrase: after the phrase’s beginning, but before its cadence. Often, composers use these techniques in combination; in fact, it’s relatively rare to find a phrase that’s expanded by only one technique.


EXAMPLE 1. Internal expansion via exact repetition in Robert Sheldon’s Bright Lights! (0:49–1:03).

Sometimes a composer repeats material, and the creates extra length.

Example 1 shows an exact repetition of a motive within a unit that creates extra length: A four-measure is followed by an expanded five-measure . The extra length results from a repeated within a unit.

EXAMPLE 2. Internal expansion via varied repetition in Mozart’s Horn Concerto, K. 447, I, mm. 1–9 (0:00–0:18).

Example 2 shows a varied repetition in which a whole unit is repeated to add extra length. A four-measure is followed by a five-measure . The continuation begins with a that expands it from the expected four measures to five.

Not all repetitions create expansion! Be careful to differentiate expansion-creating repetitions, which are unexpected, from more predictable repetitions, such as when the basic idea is repeated in a presentation.


EXAMPLE 3. Internal expansion via stretching in Schubert’s Piano Sonata D. 459, I, mm. 1–9 (0:00–0:17).

Sometimes composers will lengthen a harmony or melody by increasing its duration so that it lasts longer than expected. When that happens, we say that the unit that contains the harmony or melody has been . In Example 3, a four-measure is followed by a five-measure . The continuation’s is stretched when a [latex]\mathrm{I}^6[/latex] chord and the cadential dominant (embellished by a [latex]\mathrm{Ger}^6[/latex] and a cadential [latex]^6_4[/latex]) each last a measure long as opposed to both occurring within a single measure.


One-More-Time Technique (o.m.t.)

Coined by Janet Schmalfeldt (1989), the one-more-time technique involves three steps: 1) the music tries to cadence, 2) the attempted cadence is evaded, and 3) the music retries the cadence. The re-tried cadence often uses the same material, such that it feels like the music is “backing up,” but it may also retry the cadence with different cadential material.

EXAMPLE 4. Internal expansion via one-more-time technique in Mendelssohn, Op. 12, No. 5, “Pilgerspruch” (0:00–0:37).

In Example 4, a cadence is proposed in m. 10, but it’s evaded ([latex]\mathrm{cad^6_4 – V^4_2 – I^6}[/latex]. A one-more-time repetition of the ensues. The one-more-time unit is : notice it takes two measures (compared to one originally) for the melody to descend C–B♭–A–G, and it takes a full measure (compared to a half originally) for the cadential [latex]\mathrm{^6_4}[/latex] to resolve to [latex]\mathrm{V}^7[/latex].

Alternative Paths

An occurs when unexpected new material either temporarily or permanently causes a phrase to deviate from its expected trajectory toward a cadence. A temporary deviation is called a . Detours return to previous material from within the phrase before the phrase achieves a cadence. A permanent deviation is called a . Reroutes achieve cadences without returning to previous material from within the phrase.

EXAMPLE 5. Internal expansion via alternative path (detour) in Mendelssohn, Hebrides Overture, mm. 9–26 (0:20–0:58).

Example 5 shows a detour: the sentence’s continuation is repeated. We realize the repetition is getting “off track” when the motive in the cadential idea (m. 19) is repeated (m. 20), which did not happen in the analogous place before (m. 15). A highly-contrasting two-measure passage emerges (mm. 21–22) that leads to a return of material (mm. 23–26) similar to the cadential idea in mm. 19–20, now stretched.

EXAMPLE 6. Internal expansion via alternative path (reroute) in Maria Theresia von Paradis, Sicilienne, mm. 1–10 (0:00–0:42).

Example 6 shows a reroute: a four-measure is followed by a six-measure expanded . The consequent begins with the same as the antecedent, but its moves in a markedly different direction, one that doesn’t lead to a cadence. A new cadential idea is needed to bring the phrase to a PAC. 

Although and alternative paths both involve cadences, they are very different techniques, as explained below:

One-more-time technique Alternative path
  • Passage has tried and failed to achieve a cadence
  • Feels as though the phrase backs up to try the failed cadence again
  • Passage has not yet tried to cadence
  • Feels as though the phrase has gone off course

External Expansions

When composers add length outside of a phrase, they may add measures before the beginning () or after the cadence (). In diagrams, we indicate external expansions using dashed arcs or brackets.

The Prefix

EXAMPLE 7. External expansion via small prefix in Cécile Chaminade, “L’amour captif,” mm. 1–10 (0:00–0:13).

A occurs before the beginning of a phrase, usually taking the form of an introduction. They range in size from small to large, such as when a composer begins a symphony with a slow introduction. Example 7 shows a small prefix. As is very common with songs, this opens with an instrumental introduction before the singer enters. The introduction occurs before the phrase beginning. Note also that this phrase includes a variant on the typical . Instead of mi-fa-sol-do ([latex]\hat{3}-\hat{4}-\hat{5}-\hat{1}[/latex]), Chaminade writes di-re-sol-do ([latex]\uparrow\hat{1}-\hat{2}-\hat{5}-\hat{1}[/latex]) (mm. 8–11).

The Suffix

A suffix occurs after a phrase has cadenced. The terms in Example 8 are flexibly used to describe different types of suffix. While Example 8 provides guidelines for their use, what one person calls a , another might choose to call a . It’s more important to recognize that a given suffix adds length outside the bounds of a phrase than to worry about which term is most appropriate.

Term Avg. Length Characteristics Typical Location
Post-cadential extension (p.c.e.)
Example 10
(1-2 mm.)
  • Insubstantial: little or no melodic material
  • Often repeat the chords of the cadence (e.g. V–I) or the final tonic
  • Atypical to state an entire phrase
After the end of a phrase within a section
Example 11
(4-8 mm.)
  • Often features short motivic material that gets repeated
  • May cycle through an entire cadential progression
  • May or may not state an entire phrase
After the end of a section within a piece or movement
Example 12
(8+ mm.)
  • Substantial: may feature a new theme or reprise of a previous theme
  • Often contains multiple phrases
After the end of a piece or movement

EXAMPLE 8. Characteristics that differentiate common suffix types.

EXAMPLE 9. External expansion via suffix (post-cadential extension) in Cécile Chaminade, “Les presents” (2:31–2:57).

Example 9 shows the end of a lengthy . After the perfect authentic cadence that ends the , a two-measure post-cadential extension prolongs the final tonic via arpeggiation.[1]

EXAMPLE 10. External expansion via suffix (codetta) in Beethoven, Piano Sonata Op. 2, No. 1, mm. 36–48 (0:45–0:58).

In Example 10, a lengthy phrase ends the exposition of the piano sonata with a PAC in A♭ major at m. 41. The cadence is followed by a codetta: notice that it features a repeated two-measure unit harmonized with the cadential bass line fi-sol-do ([latex]\uparrow\hat{4}-\hat{5}-\hat{1}[/latex]).

Timestamp: 4:52 5:03 5:32
Event: Introduction returns in varied form A second variation on the introduction begins Coda begins. its material is drawn from the second theme (from 2:00)

EXAMPLE 11. External expansion via suffix () in Shostakovich, Festive Overture



EXAMPLE 12. Contraction in Stéphan Elmas, Piano Concerto No. 1, III, mm. 15–21 (32:21–32:28).

Contractions occur less frequently than expansions. A occurs when a phrase is shorter than we might expect it to be.

In Example 12, a four-measure is followed by a three-measure continuation. Given the length of the compound basic idea, we might have expected the continuation to be four measures long to create proportional balance. As you listen, notice how the cadence feels abrupt, a feeling that usually accompanies contraction.


Further Reading
  • Jarvis, Brian and John Peterson. 2019. “Alternative Paths, Phrase Expansion, and the Music of Felix Mendelssohn.” Music Theory Spectrum 41/2.
  • Schmalfeldt, Janet. 1992. “Cadential Processes: The Evaded Cadence and the ‘One More Time’ Technique.” Journal of Musicological Research 12/1–2.
  1. Analyzing expansion techniques (.pdf, .docx). Asks students to name: segment and label the form of excerpts and identify the location of any expansion technique(s). Optional harmonic analysis included.
  2. Analyzing multiple expansion techniques (.pdf, .docx). More complicated examples than in worksheet 1. Each excerpt is significantly expanded.
  3. Recomposing to remove expansions (.pdf, .docx). Asks students to recompose excerpts from worksheet 1 to remove the expanded portion of the archetypal form.

Media Attributions

  • Example_001_Repetition_Sheldon_Bright_Lights © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
  • Private: combined-Example_002b_Repetition_Mozart_447-3 © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
  • Example_003a_Stretching_Schubert_459 © EXAMPLE 2. Internal expansion via varied repetition in Mozart's Horn Concerto, K. 447, I, mm. 1–9 (0:00–0:18). is licensed under a CC BY-SA (Attribution ShareAlike) license
  • Slide5-6 © John Peterson and Megan Lavengood
  • Slide8-10 © John Peterson and Megan Lavengood
  • Slide10-11 © John Peterson and Megan Lavengood
  • Slide12-13 © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
  • Example_010_Chaminade_Presents © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
  • Example_011_codetta_Beethoven_2_1 © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
  • Example_013_Contraction_Elmas_PC_1_III © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license

  1. The recording linked is the only commercial recording of the piece. We hope more people will record this beautiful work.


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