Getting Started
Having learned to identify individual chords and their basic functions, we now turn to how these chords are combined to create musical punctuation. Cadences are the harmonic and melodic formulas that conclude musical phrases, much like commas and periods in language. Understanding them is crucial for analyzing the structure and flow of a musical work.
What You Should Be ableable to Do
Identify Plagal, Phrygian Half, and Deceptive cadences in notated musical excerpts.
Aurally distinguish between different cadence types in performed music.
Provide a correct Roman numeral analysis for a phrase ending with one of these cadences.
Explain the harmonic function of the chords that create these specific cadences.
Describe the unique characteristics of the Phrygian Half Cadence, including its typical mode and inversion.
Key Concepts & Analysis
Harmonic Functions as Musical Grammar
In tonal music, chords do not appear in a random order. They follow a logical syntax based on their function, which describes their role in creating or resolving musical tension. The three primary functions are Tonic, Predominant, and Dominant.
Tonic (T): The point of rest and stability. The tonic chord (I or i) is the home base of the key.
Predominant (PD): Creates moderate tension and prepares for the arrival of the dominant. Common predominant chords include IV (iv) and ii (ii°).
Dominant (D): The point of maximum tension, which demands resolution to the tonic. The dominant chord (V) and the leading-tone chord (vii°) serve this function.
The most common and foundational harmonic progression in Western music follows the pattern: Tonic → Predominant → Dominant → Tonic. This progression establishes the key, moves away from it, builds tension, and provides a satisfying resolution. Cadences are specific, two-chord gestures that occur at the end of this progression, or sometimes offer an alternative path.
Cadences: The Punctuation of a Phrase
A cadence is a melodic and harmonic endpoint of a phrase, section, or piece of music. It provides a sense of closure, ranging from a temporary pause to complete finality. While many cadences involve the dominant-tonic relationship (V–I), this section explores important variants that use predominant function or subvert listener expectations.
Cadences Using Predominant Function
Some cadences derive their unique character from the use of a predominant chord in a concluding role.
The Plagal Cadence: IV–I or iv–i
The Plagal Cadence consists of the progression IV–I (in major) or iv–i (in minor). It moves from a predominant chord directly to the tonic, bypassing the dominant function entirely.
Function: This cadence provides a sense of closure, but it is gentler and less decisive than a dominant-to-tonic cadence. The lack of a leading tone resolving to the tonic reduces its feeling of finality.
Context: Because of its less emphatic nature, the plagal cadence is often used as a tag or extension after a strong authentic cadence has already occurred, confirming the piece's conclusion. It is famously known as the "Amen" cadence for its frequent use at the end of hymns.
Analysis: When you see a phrase ending with the progression IV–I or iv–i, you are observing a plagal cadence. For example, in C major:
F major chord (F-A-C) → C major chord (C-E-G).
The Phrygian Half Cadence: iv⁶–V (Minor Keys Only)
The Phrygian Half Cadence is a specific and highly expressive type of half cadence that occurs only in minor keys. A half cadence is any cadence that ends on the dominant (V) chord, creating a feeling of a pause or an open question. The Phrygian Half Cadence is defined by the specific progression iv⁶–V.
Function: The iv⁶ chord serves a predominant function, preparing the arrival of the dominant. However, the specific voice leading of this progression gives it a unique, dark, and archaic sound.
Defining Feature: The most critical feature is the descending half-step motion in the bass from scale degree ^6 to scale degree ^5. For example, in a minor, the bass would move from F down to E. This melodic half-step is characteristic of the Phrygian mode, from which the cadence gets its name.
Analysis: To identify a Phrygian Half Cadence, look for three things: (1) the piece is in a minor key, (2) the phrase ends on a V chord, and (3) the V chord is preceded by a iv chord in first inversion (iv⁶).
Cadences That Subvert Expectation
While most music relies on fulfilling harmonic expectations, composers can create interest and drama by deliberately avoiding them.
The Deceptive Cadence: V–vi or V–VI
The Deceptive Cadence occurs when the ear expects a V–I (or V–i) authentic cadence, but the dominant chord resolves instead to the submediant chord: vi in a major key, or VI in a minor key.
Function: This cadence is a powerful tool for creating surprise. The dominant chord builds strong tension, but instead of providing the expected stable tonic resolution, it moves to another chord that contains the tonic note (scale degree ^1) but is not the tonic chord itself. This "deceives" the listener.
Effect: The primary effect of a deceptive cadence is to extend a phrase. By avoiding the expected closure, the music is propelled forward, often initiating a new idea or a restatement of the previous one.
Analysis: When you see a V chord followed by a vi or VI chord at the end of a phrase, you have identified a deceptive cadence. For example, in C major:
G major chord (G-B-D) → a minor chord (A-C-E).
Data & Organization Tools
This map illustrates the primary pathways of functional harmony, including the alternative routes created by the plagal and deceptive cadences.
Harmonic Function Map
Tonic Area (Stability)
Chords: I, vi (i, VI)
Path: Can move to Predominant or Dominant.
Predominant Area (Preparation)
Chords: IV, ii (iv, ii°)
Path: Moves to Dominant.
Plagal Cadence Path: IV (iv) can move directly back to I (i).
Dominant Area (Tension)
Chords: V, vii°
Path: Moves to Tonic.
Deceptive Cadence Path: V can move to vi (VI).
Evidence Bank
Cadence: The two-chord harmonic and melodic formula that concludes a musical phrase.
Predominant Function: The harmonic role of preparing the dominant chord, typically fulfilled by IV/iv or ii/ii°.
Plagal Cadence: A cadence formed by the progression IV–I or iv–i; a predominant-to-tonic conclusion.
Phrygian Half Cadence: A specific half cadence in minor keys, iv⁶–V, characterized by the bass motion ^6–^5.
Deceptive Cadence: A cadence where V resolves to vi (or VI in minor), subverting the expectation of resolution to the tonic.
Half Cadence: Any cadence ending on the V chord, creating a sense of pause or expectation.
Authentic Cadence: The strongest cadence, formed by the progression V–I (or V–i), which the deceptive cadence avoids.
Submediant Chord: The vi chord (in major) or VI chord (in minor), which serves as the substitute for the tonic in a deceptive cadence.
Skill Snapshots
Functional
Progression 1:
I – vi – IV – I(in G major: G – em – C – G)- Why it works: This phrase ends with a Plagal Cadence (IV–I), providing a gentle conclusion after a standard tonic expansion (I–vi).
Progression 2:
i – iiø⁶/₅ – iv⁶ – V(in d minor: dm – eø⁶/₅ – gm⁶ – A)- Why it works: This phrase culminates in a Phrygian Half Cadence (iv⁶–V), creating a dramatic pause defined by the predominant-to-dominant motion in a minor key.
Progression 3:
I – IV – V – vi(in F major: F – B♭ – C – dm)- Why it works: This progression builds strong expectation with the standard T–PD–D setup, but the final V–vi motion creates a Deceptive Cadence, avoiding closure and extending the phrase.
Voice-Leading
Rule → Effect 1: In a Phrygian Half Cadence (iv⁶–V), the bass must move by descending half step (^6–^5). → This melodic motion is the defining characteristic and gives the cadence its unique sound.
Rule → Effect 2: In a Deceptive Cadence (V–vi), the leading tone (^7) in an upper voice should still resolve up to ^1. → This maintains melodic tendency and creates a smooth connection despite the surprising harmonic shift in the bass.
Rule → Effect 3: In a Plagal Cadence (IV–I), scale degree ^1 is a common tone between both chords. → Keeping this common tone in the same voice creates an exceptionally smooth and connected sound, contributing to the cadence's gentle quality.
Form
Baseline Phrase: A phrase ending with an authentic cadence (
...ii–V–I) feels complete and final, suitable for ending a section or piece.Contrast 1 (Pause): A phrase ending with a Phrygian Half Cadence (
...iv⁶–V) feels incomplete and highly dramatic, demanding continuation. It creates a moment of suspense.Contrast 2 (Surprise): A phrase ending with a Deceptive Cadence (
...V–vi) feels like an interruption. It avoids the expected finality and often triggers a repetition or extension of the phrase.Continuity: A Plagal Cadence (
...IV–I) often appears after a conclusive authentic cadence. It does not create new formal sections but rather confirms the finality that has already been established, acting as a coda or "epilogue" to the phrase.
Common Misconceptions & Clarifications
"Any IV–I progression is a plagal cadence." A progression must occur at the end of a musical phrase to be considered a cadence. A IV–I motion in the middle of a phrase is simply a common harmonic progression.
"A half cadence is the same as a Phrygian Half Cadence." The Phrygian Half Cadence is a very specific type of half cadence. Most half cadences (e.g., I–V, ii–V) are not Phrygian; the term applies only to the iv⁶–V progression in a minor key.
"In a deceptive cadence, all rules of resolution are broken." While the bass moves unexpectedly, the tendency of the leading tone (^7) to resolve to the tonic (^1) remains. This voice-leading principle is almost always followed in an upper voice.
"Plagal and deceptive cadences are weak and unimportant." These cadences are essential expressive tools. The deceptive cadence is critical for building longer and more complex musical forms, while the plagal cadence provides a unique color of solemn finality.
Summary
Cadences provide the structural punctuation for musical phrases. Beyond the foundational authentic cadence, several other types serve crucial expressive and formal roles. The Plagal Cadence (IV–I) uses a predominant-to-tonic motion to create a gentle, affirmative conclusion, often used to confirm finality. The Phrygian Half Cadence (iv⁶–V in minor) is a specialized half cadence whose unique sound comes from its characteristic descending half-step in the bass. Finally, the Deceptive Cadence (V–vi) creates surprise by avoiding the expected tonic resolution, effectively extending the musical thought. Identifying these cadences by their harmonic function and characteristic sound is a fundamental skill for understanding musical narrative and structure.