Part Writing of Secondary Leading Tone Chords - AP Music Theory Study Guide

Getting Started

Having mastered the function and spelling of secondary dominant chords, we now turn to their close relatives: secondary leading-tone chords. These chords provide another, often more subtle, way to create temporary tonal centers within a key. Their proper use depends on a strict application of the voice-leading principles you learned for primary leading-tone chords.

What You Should Be Able to Do

• Analyze a musical score to identify and label secondary leading-tone chords with Roman numerals.

• Realize a figured bass or Roman numeral progression that includes secondary leading-tone chords, applying correct voice-leading procedures.

• Compose a four-part chorale-style phrase incorporating a secondary leading-tone chord to tonicize a diatonic harmony.

• Identify and correct voice-leading errors—such as incorrect resolutions or doublings—in a given musical example containing these chords.

• Provide the correct Roman numeral analysis for a secondary leading-tone chord in any given major or minor key.

Key Concepts & Analysis

The part-writing of secondary leading-tone chords is governed by a specific set of voice-leading constraints that carry over directly from their primary counterparts. Understanding these rules is essential for creating smooth, grammatically correct harmonic progressions.

The Foundation: Voice Leading for Primary Leading-Tone Chords

Before applying these rules in a secondary context, we must review the procedures for the diatonic leading-tone chord (vii° or viiø7).

A leading tone is the seventh scale degree (^7) of a key, so named because of its strong melodic tendency to resolve up by half step to the tonic (^1). A leading-tone chord is the triad or seventh chord built on the leading tone.

The core voice-leading principles are:

1. Resolution of the Leading Tone: The root of the chord (^7) must almost always resolve up by step to the tonic (^1).

2. Resolution of the Tritone: Leading-tone triads and seventh chords contain a tritone, a dissonant interval of an augmented fourth or diminished fifth. This interval must be resolved. In a vii° chord, the tritone is between the root (^7) and the chordal fifth (^4). The ^7 resolves up to ^1, and the ^4 resolves down to ^3.

3. Doubling: Never double the leading tone (the root of the chord). Its strong tendency to resolve makes doubling it create parallel octaves upon resolution. In a vii°6 chord, it is standard practice to double the chordal third (the bass note, ^2) or the chordal fifth (^4).

4. Inversions: Leading-tone chords appear most frequently in first inversion (vii°6). Placing the more stable second scale degree in the bass softens the dissonance of the tritone and creates better counterpoint with the upper voices.

5. Resolution of the Chordal Seventh: If the chord is a seventh chord (e.g., viiø7), the chordal seventh (the note a seventh above the root) must resolve down by step.

Applying the Rules to Secondary Contexts

A secondary leading-tone chord is a leading-tone chord that resolves to a diatonic chord other than the tonic. This process of making a non-tonic chord sound like a temporary tonic is called tonicization. The voice-leading rules remain identical; you simply apply them relative to a new, temporary tonic.

Let's part-write a vii°6/V chord in C major.

• Target Chord: The chord of resolution is V (G major). This is our temporary tonic.

• Temporary Leading Tone: The leading tone to G is F#. This F# is the root of our secondary leading-tone chord.

• Spelling the Chord: A diminished triad on F# is F#–A–C.

• Inversion: The chord is in first inversion (6), so the chordal third, A, is in the bass.

The voice-leading procedure is as follows:

1. Resolve the Temporary Leading Tone: The root of the secondary chord (F#) must resolve up by half step to the root of the target chord (G). This is the most important step.

2. Resolve the Tritone: The tritone in our F#° chord is between the root (F#) and the fifth (C). The F# resolves up to G, and the C resolves down to B (the third of the G major chord). This contrary motion is crucial.

3. Handle the Doubled Note: The bass note is A (^2 of the temporary key of G). In a vii°6 chord, this is a common note to double. If you double the A, one A can move to G and the other to D to complete the G major chord.

4. Check for Parallels: Ensure no parallel perfect fifths or octaves have been created between any two voices. The strict resolution of the temporary leading tone and the tritone helps prevent these errors.

5. Chordal Sevenths: If the chord were viiø7/V (F#–A–C–E), the chordal seventh (E) would need to resolve down by step to D.

This exact process applies to any secondary leading-tone chord, whether it resolves to ii, iii, IV, V, or vi. Always identify the temporary tonic first, then apply the fundamental rules of resolution and doubling.

Data & Organization Tools

This table shows the most common secondary leading-tone triads in a major key, their target of resolution, and the crucial temporary leading tone that must resolve upward.

Evidence Bank

• Secondary Leading-Tone Chord: A chromatically altered leading-tone chord that resolves to a diatonic chord other than the tonic, creating tonicization.

• Tonicization: The compositional technique of making a non-tonic chord sound like a temporary tonic, usually by preceding it with its own dominant or leading-tone chord.

• Temporary Leading Tone: The root of the secondary leading-tone chord. It is always a chromatic pitch and is located a half step below the root of the target chord.

• Resolution of the Temporary Leading Tone: The defining voice-leading characteristic; this note must resolve up by a half step to the root of the chord of resolution.

• Resolution of the Chordal Seventh: In a secondary leading-tone seventh chord, the seventh above the root must resolve down by diatonic step.

• Tritone Resolution: The two notes forming the tritone within the secondary chord resolve in contrary motion by step.

• First Inversion (6): The most common and smoothest-sounding inversion for secondary leading-tone chords, placing a more stable scale degree in the bass.

• Diminished Triad (°): The default quality for a secondary leading-tone triad, consisting of a root, minor third, and diminished fifth.

Skill Snapshots

• Functional:

  1. I – vii°6/V – V – I: The most common usage, intensifying the move to the dominant before an authentic cadence.

  2. I – vii°6/ii – ii6 – V – I: A sophisticated way to approach the pre-dominant ii chord, creating a smooth chromatic bass line.

  3. I – vii°6/vi – vi – IV – V – I: Used to tonicize the submediant, often at the beginning of a new phrase or as part of a deceptive progression.

• Voice-Leading:

  1. Rule: The temporary leading tone must resolve up by half step. Effect: This creates a powerful melodic pull to the root of the target chord, confirming the tonicization for the listener.

  2. Rule: The chordal seventh (if present) must resolve down by step. Effect: This smoothly resolves the chord's primary dissonance and adheres to the fundamental principles of treating all seventh chords.

  3. Rule: Never double the temporary leading tone. Effect: Doubling this highly unstable tone would create forbidden parallel octaves upon its required resolution, disrupting the independence of the voices.

• Form:

  1. Baseline Phrase: A simple phrase ending in an authentic cadence, such as I – IV – V – I.

  2. Intensified Cadence: Using vii°6/V to strengthen the arrival of the dominant before a cadence: I – IV – vii°6/V – V – I.

  3. Phrase Elaboration: Using a secondary leading-tone chord to create a smoother, more chromatic connection between chords within a phrase: I – vii°6/ii – ii6 – V – I.

Common Misconceptions & Clarifications

• Misconception: Forgetting which note is the temporary leading tone.

  • Clarification: The temporary leading tone is always the root of the secondary leading-tone chord. Its name in the analysis (e.g., the "vii" part) tells you its function.

• Misconception: Confusing the Roman numeral vii°/V with V/vii°.

  • Clarification: The numeral after the slash always indicates the chord of resolution, or the temporary tonic. vii°/V is the "leading-tone chord of five," and it resolves to V.

• Misconception: Doubling the root of the secondary leading-tone chord.

  • Clarification: Just like a primary leading tone, a temporary leading tone is an active, unstable pitch that demands resolution. It should never be doubled. In first inversion, doubling the bass note (the chordal third) is the safest and most common practice.

• Misconception: Resolving the temporary leading tone incorrectly.

  • Clarification: The upward, half-step resolution of the temporary leading tone is non-negotiable. Failure to do this negates the entire function of the chord.

Summary

Secondary leading-tone chords are chromatic harmonies that tonicize diatonic chords, functioning as the vii° of a temporary key. Their part-writing is not based on new principles but is a direct application of the rules for primary leading-tone chords. The essential procedures are to resolve the temporary leading tone up by a half step to the root of the target chord, resolve any chordal seventh down by step, and correctly resolve the internal tritone. These chords are most often used in first inversion to create smoother bass lines and to avoid placing the unstable leading tone in the bass. Mastering their voice leading adds a significant level of chromatic sophistication to your harmonic vocabulary.