III. Form
Hybrid Phrase-level Forms
John Peterson
Key Takeaways
- A combines the beginning of one archetype with the ending from another.
- Possible beginnings are , , or .
- Possible endings are , , or .
- Although any beginning could be combined with any ending, some pairings are more common than others (see Example 7).
What’s a hybrid form?
Earlier we looked at two phrase-level formal : the and the .
We found that these forms divide into two parts. A sentence divides into two : a and a A period divides into two : an and a

A 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 followed by a , 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 , 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 and one more possible ending. Below we’ll outline these new beginnings and endings, and provide ways to help distinguish between them.
Beginnings
New: The Compound Basic Idea (c.b.i.)

A is an antecedent without a cadence (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 HC that might have appeared there.
Summary: The 3 Beginning Types
The 3 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.
Endings
New: Cadential (cad.)

A ending harmonizes a particular bass pattern (Example 4).[2]
The is: M-F-S-D.[3] The common harmonization of each of these notes is:
- Mi: I6
- Fa: ii6 or IV
- Sol: V(7) (often elaborated with cadential [latex]^6_4[/latex])
- Do: I
This core M-F-S-D bass line may be embellished. A common embellishment is to the dominant by adding Fi before Sol, making the bass line M-F-Fi-S-D.
The clearest cadential endings are four measures long with one bass note per measure.
Summary: The 3 Ending Types
The 3 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 | M-F-S-D 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 3 possible beginnings and 3 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 Phrase-level forms 2.
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 |
---|---|
Antecedent | Consequent |
Compound basic idea (c.b.i.) | Continuation |
Presentation | Cadential |
EXAMPLE 6. Possible beginnings and endings.
Form | Degree of commonality |
---|---|
pres.+cont. (sentence) ant.+cons. (period) |
very common |
c.b.i.+cons. c.b.i.+cont. ant.+cont. |
slightly less common |
c.b.i.+cad. c.b.i.+cad. |
occasional |
pres.+cad. pres.+cons. |
rare or non-existent |
EXAMPLE 7. Pairings of beginnings and endings sorted by degree of commonality.
- EXAMPLE 8. An antecedent + continuation in Beethoven, Piano Sonata Op. 13, II, mm. 1–8 (0:00–0:31).
- EXAMPLE 9. A compound basic idea + continuation in Haydn, Piano Sonata Hob. XVI:35, I, mm. 1–8 (0:00–0:10).
- EXAMPLE 10. An antecedent + cadential in Haydn, String Quartet Op. 64, No. 4, II, mm. 1–8 (0:00–0:10).
- EXAMPLE 11. A compound basic idea + cadential in Haydn, Symphony 95, III, mm. 1–8 (0:00–0:10).
- EXAMPLE 12. A compound basic idea + consequent in Haydn, Symphony 97, III, mm. 1–8 (0:00–0:11).
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.

-
Caplin, William Earl. 2013. Analyzing Classical Form: An Approach for the Classroom. New York: Oxford University Press.
- 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.
- Analyzing forms with multiple possibilities (.pdf, .docx). Asks students to identify preferred and plausible alternative interpretations for several excerpts. Also includes band music.
- 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
- Example_001_Ant+Cont © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
- Example_002a_compound_basic_idea © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
- Example_004a_cadential © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
- Example_013a_Listening_Diagram_Caplin © John Peterson and Megan Lavengood is licensed under a CC BY-SA (Attribution ShareAlike) license
- 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 2 c.b.i. units. It's "compound" in the sense that these large basic ideas are themselves comprised of two units: a b.i. and a c.i. ↵
- 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. ↵
- This can also occur in minor, of course, as Me-F-S-D. ↵
A hybrid form is one that combines aspects of the sentence and the period into one phrase-level form.
A phrase comprised of a basic idea followed by a contrasting idea that ends with a weak cadence.
A subphrase consisting of a basic idea and its repetition. Presentations don't usually end with cadences.
A compound basic idea (c.b.i.) is an antecedent without a cadence. It consists of a basic idea followed by a contrasting idea. The reason it's called "compound" is that it often forms the basic idea for a large sentence, one in which the presentation is 8 measures long and consists of two four-measure c.b.i. units as stand-ins for the archetypal two-measure b.i.s
A phrase comprised of a basic idea followed by a contrasting idea that ends with a strong cadence. It usually forms the second half of a phrase-level form.
A subphrase that features a mix of any of the following: fragmentation, increase in harmonic rhythm, increase in surface rhythm, or sequences. Continuations end with a cadence and are usually found in the second half of a theme.
One of the three common ending types. Its distinguishing characteristic is its bass line: M-F-S-D, which may be elaborated with chromaticism.
Phrases that are "archetypal" or that follow an archetype are related to the sentence, the period, or one of the hybrid phrase-level forms.
A special kind of phrase consisting of a presentation and a continuation.
A phrase-level form that consists of two phrases: an antecedent and a consequent.
The unit of music that need not end with a cadence and which is one level smaller than a phrase, but one level larger than an idea. Subphrases do not exist in all phrase-level forms. Periods, for example, do not contain subphrases. Sentences contain two subphrases: a presentation and a continuation.
A relatively complete musical thought that exhibits trajectory toward a goal. In much music, that goal is a cadence; so we might also say that a phrase is a relatively complete musical thought that ends with a cadence.
Basic ideas are short units that are typically associated with beginnings. They don't usually end with cadences, and they often establish tonic. They are they first units we hear in a presentation, an antecedent, a consequent, and a compound basic idea.
A small unit that contrasts with the material that came immediately before it, usually in terms of contour. It's featured in the antecedent and the compound basic idea.
Making unit sizes smaller than the previously established size. For example, if units had previously been 2 measures long, fragments might be 1 measure long.
A core bass pattern is the basic series of notes that defines a common progression. This series of notes may be embellished with other, less important notes, but the pattern is still recognizable because the basic series is still present.
The process by which a non-tonic triad is made to sound like a temporary tonic. It involves the use of secondary dominant or leading-tone chords.