III. Form

Hybrid Phrase-Level Forms

John Peterson

Key Takeaways

Chapter Playlist

What’s a hybrid form?

In The Phrase, Archetypes and Unique Forms, we looked at two phrase-level formal archetypes: the sentence and the period.

We found that these forms divide into two parts. A sentence divides into two subphrases: a presentation and a continuation. A period divides into two phrases: an antecedent and a consequent.

Example 1. An antecedent + continuation in Beethoven, Piano Sonata Op. 13, II, mm. 1–8 (0:00–0:32).

A hybrid form occurs when the beginning of one archetype is paired with the ending from another archetype. In Example 1, an antecedent is followed by a continuation.

  • How do we know the first part is an antecedent rather than a presentation?
    • It ends with a weaker cadence, whereas presentations don’t end with cadences.
    • It has a basic idea followed by a contrasting idea, whereas presentations have a basic idea followed by a repetition of the basic idea.
  • How do we know the second part is a continuation rather than a consequent?
    • Rather than beginning as consequents do with a basic idea, it begins with fragmentation, which is characteristic of continuations.
    • It begins with a feeling of instability created by the dominant that continues after the half cadence, rather than the stability that’s typical of a consequent’s beginning.

So far, we know two beginnings (presentation and antecedent) and two endings (continuation and consequent), but there’s actually one more possible beginning (compound basic idea) and one more possible ending (cadential). Below, we’ll outline these new beginnings and endings and provide ways to help distinguish between them.


New: The Compound Basic Idea (c.b.i.)

A compound basic idea in Haydn’s Piano Sonata in C, Hob. XVI:35, I, mm. 1–8.
Example 2. A compound basic idea in Haydn’s Piano Sonata in C, Hob. XVI:35, I, mm. 1–8 (0:00–0:05).

A compound basic idea (c.b.i.) is an antecedent without a cadence, as seen in Example 2.[1]

  • How is Example 2 like an antecedent?
    • It contains a basic idea followed by a contrasting idea.
  • How is Example 2 different from an antecedent?
    • It doesn’t end with a cadence. Notice how the bass sits on G across mm. 3–4: although the melody comes to a point of rest, the lack of harmonic motion in the bass evades the half cadence (HC) that might have appeared there.

Summary: The Three Beginning Types

The three beginnings that appear in hybrid phrase-level forms are antecedent, compound basic idea, and presentation. Example 3 provides a summary of the characteristics that differentiate each of these beginnings.

Beginning Ends with cadence? First idea Second idea
antecedent Yes b.i. c.i.
compound basic idea No b.i. c.i.
presentation No b.i. b.i.

Example 3. Characteristics that differentiate beginnings.


New: Cadential (cad.)

A cadential ending in Haydn, String Quartet Op. 64, No. 4, II, mm. 1–8.
Example 4. A cadential ending in Haydn, String Quartet Op. 64, No. 4, II, mm. 1–8 (0:05–0:10).

A cadential (cad.) ending harmonizes a particular bass pattern (demonstrated in Example 4).[2]

The core bass pattern is mi–fa–sol–do [latex](\hat3-\hat4-\hat5-\hat1)[/latex].[3] The common harmonization of each of these notes is:

  • mi [latex](\hat3)[/latex]: I6
  • fa [latex](\hat4)[/latex]: ii6 or IV
  • sol [latex](\hat5)[/latex]: V(7) (often elaborated with cadential [latex]^6_4[/latex])
  • do [latex](\hat1)[/latex]: I

This core mi–fa–sol–do [latex](\hat3-\hat4-\hat5-\hat1)[/latex] bass line may be embellished. A common embellishment is to tonicize the dominant by adding fi before sol ([latex](\uparrow\hat4-\hat5)[/latex], making the bass line mi–fa–fi–sol–do [latex](\hat3-\hat4-\uparrow\hat4-\hat5-\hat1)[/latex].

The clearest cadential endings are four measures long with one bass note per measure.

Summary: The Three Ending Types

The three endings that appear in hybrid phrase-level forms are consequent, continuation, and cadential. Example 5 provides a summary of the characteristics that differentiate each of these endings.

Ending Cadence Bass Ideas
Consequent PAC/IAC. Not HC. Varies b.i. + c.i.
Continuation HC, IAC, or PAC. Varies vary, but often divided 1+1+2 or 2+2
Cadential PAC/IAC. Not HC. Mi−fa−sol−do [latex](\hat3−\hat4−\hat5−\hat1)[/latex] or an elaboration of that line. Either 2+2 or indivisible. Never features fragmentation.

Example 5. Characteristics that differentiate endings.

Hybrid Possibilities and Examples

The three possible beginnings and three possible endings are shown in Example 6. While any beginning on the left could be paired with any ending on the right, Example 7 shows that there are some pairings that are more common than others.

Below, we provide examples for all hybrids in the “slightly less common” and “occasional” categories (Examples 8–12). We already provided examples of the period and sentence in The Phrase, Archetypes, and Unique Forms.

The examples we provide in this chapter are all eight-measure archetypes, but as we show in the next chapter, these forms can be any length.

Beginnings Endings
Compound basic idea (c.b.i.)

Example 6. Possible beginnings and endings. Any beginning on the left can theoretically pair with any ending on the right.

Form Degree of commonality
pres.+cont. (sentence)
ant.+cons. (period)
very common
slightly less common
rare or non-existent

Example 7. Pairings of beginnings and endings sorted by degree of commonality.

Listening to Phrase-level Forms

With so many possibilities, it might seem overwhelming to try to sort through the various possibilities. Example 13 offers a suggested listening strategy that can help determine what kind of beginning and ending you’re hearing.

Suggested process for listening to phrase-level forms: (a) what to listen for in beginnings, and (b) what to listen for in endings.
Example 13. Suggested process for listening to phrase-level forms: (a) what to listen for in beginnings, and (b) what to listen for in endings.
Further Reading
  • Caplin, William Earl. 2013. Analyzing Classical Form: An Approach for the Classroom. New York: Oxford University Press.
  1. Analyzing hybrid forms (.pdf, .docx). Provides excerpts and asks students to indicate which term best describes the first and second half of each. Optional harmonic analysis included. Worksheet playlist
  2. Analyzing forms with multiple possibilities (.pdf, .docx). Asks students to identify preferred and plausible alternative interpretations for several excerpts. Also includes band music. Worksheet playlist
  3. Composing phrase-level forms (.pdf, .docx). Asks students to compose a phrase-level form given a description. Provides a basic idea bank to give students a start.

Media Attributions

  1. What is "compound" about the compound basic idea? It often functions as the basic idea of a large sentence, one that is sixteen measures in length, where the presentation is eight measures long and comprises two c.b.i. units. It's "compound" in the sense that these large basic ideas are themselves composed of two units: a b.i. and a c.i.
  2. What is the difference between a cadential idea and cadential ending? The cadential idea comes at the end of a continuation, and essentially, the cadential ending is like the cadential idea being expanded to four measures and replacing the continuation. That means that "cadential" can occur at two formal levels: the idea level and the subphrase level.
  3. This can also occur in minor, of course, as me–fa–sol–do [latex](\downarrow\hat3-\hat4-\hat5-\hat1)[/latex].


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