Unit Big Picture
This unit expands the foundational Tonic-Dominant harmonic model by introducing the Predominant function, which serves as a crucial bridge creating forward motion toward the dominant. Students will learn to write and identify common predominant chords (IV, ii, and their sevenths), adding significant length and interest to musical phrases. The unit also introduces new harmonic possibilities with the vi and iii chords, and explores the special voice-leading conventions of second-inversion triads, particularly the cadential 6/4 chord.
Core Threads
Thread 1: Functional Harmony & Cadences
Expanding the Phrase Model: Moving beyond the simple Tonic-Dominant relationship to the more complete Tonic-Predominant-Dominant-Tonic (T-PD-D-T) model, which underpins most common practice harmony.
Refining Cadential Formulas: Learning how predominant chords strengthen cadences and how the deceptive cadence (V-vi) creates harmonic surprise to extend a phrase.
Thread 2: Voice-Leading & Texture
Managing Dissonance: Introducing new types of controlled dissonance, including the 7th of predominant seventh chords and the unstable 4th and 6th above the bass in 6/4 chords.
Chord-Specific Procedures: Mastering the specific voice-leading rules for common progressions (e.g., IV-V, ii-V) and for handling the strict preparation and resolution of the cadential 6/4 chord.
Concept Progression
| Step | Concept | Builds On | Why It Matters |
|---|---|---|---|
| 1 | Basic Predominant Function | Tonic & Dominant Functions | Establishes the standard T-PD-D-T phrase model. |
| 2 | Deceptive Motion | Authentic Cadences | Introduces harmonic surprise and phrase extension (V-vi). |
| 3 | Predominant Seventh Chords | Diatonic Triads & V⁷ | Adds intensity and chromaticism to the predominant function. |
| 4 | The Cadential 6/4 | Inversions & Dissonance | Teaches a critical harmonic-textural device to embellish cadences. |
Turning Points
| New Tool Introduced | What It Enables | Why It Mattered |
|---|---|---|
| Predominant Chords (IV, ii) | The complete T-PD-D-T harmonic phrase model. | Creates smoother, more compelling harmonic motion to the dominant. |
| The Cadential 6/4 Chord | A specific, powerful embellishment of the dominant at a cadence. | Standardizes a key textural and harmonic gesture in tonal music. |
| The Deceptive Cadence | Avoidance of an expected tonic resolution (V to vi). | Creates harmonic surprise, delays closure, and extends phrases. |
Unit Evidence Bank
Predominant Function: The harmonic role of chords (typically IV and ii) that prepare the arrival of the dominant.
Deceptive Cadence: A cadence ending on V-vi (or V-VI in minor), creating an unexpected move away from the tonic.
Plagal Cadence: A cadence ending on IV-I, often called the "Amen" cadence.
Cadential 6/4: A second-inversion tonic chord that embellishes the dominant at a cadence, functioning as a dissonance that resolves to the V chord.
Passing 6/4: A 6/4 chord that connects a root-position chord with its first-inversion form, typically with stepwise motion in the bass.
Pedal 6/4: A 6/4 chord where the bass note is sustained from the previous chord, and the upper voices move to create the 6/4 sonority before resolving.
Supertonic: The second scale degree, or the triad built on it (ii or ii°). A common predominant chord.
Subdominant: The fourth scale degree, or the triad built on it (IV or iv). The other primary predominant chord.
Topic Navigator
| Topic Title | What This Adds (≤10 words) |
|---|---|
| 5.1: Adding Predominant Function | Introduces IV and ii to expand the harmonic phrase. |
| 5.2: The vi (VI) Chord | Adds deceptive motion and tonic expansion possibilities. |
| 5.3: Predominant Seventh Chords | Intensifies predominant function with ii⁷ and IV⁷ chords. |
| 5.4: The iii (III) Chord | Introduces a less common diatonic chord and its function. |
| 5.5: Cadences and Predominant Function | Refines cadence types using new predominant chords. |
| 5.6: Cadential 6/4 Chords | Details the specific voice-leading of this cadential embellishment. |
| 5.7: Additional 6/4 Chords | Covers non-cadential 6/4 chords like passing and pedal. |
Exam Skills Focus
Functional: Using predominant chords (IV, ii) to create logical harmonic momentum toward the dominant.
Voice-Leading: Resolving the dissonant 4th of a cadential 6/4 chord down by step to the 3rd of the V chord.
Aural: Distinguishing the finality of an authentic cadence (V-I) from the surprise of a deceptive cadence (V-vi).
Common Misconceptions & Clarifications
Misconception: All 6/4 chords are interchangeable. → Clarification: 6/4 chords are defined by their context and voice-leading; the cadential, passing, and pedal 6/4 have different functions and rules.
Misconception: The vi chord is a predominant chord. → Clarification: The vi chord most often expands tonic function or follows a dominant in a deceptive cadence; it rarely moves directly to V.
Misconception: A chord's function is determined only by its root. → Clarification: Function is determined by context. A tonic I⁶/₄ at a cadence functions as part of the dominant, not as a true tonic.
Summary
Unit 5 marks a major step in understanding tonal harmony by introducing the predominant function, which completes the core T-PD-D-T phrase model. By learning to use chords like IV and ii, students can create more sophisticated and grammatically correct progressions. This unit also adds crucial tools for harmonic variety, such as the deceptive cadence for extending phrases and the cadential 6/4 for embellishing them. Mastering the specific voice-leading conventions for these new chords and situations is essential for both fluent part-writing and accurate musical analysis.