Getting Started
Building upon your knowledge of diatonic harmony and voice leading, this section introduces secondary dominant chords. These chords add chromatic color and harmonic interest by temporarily treating a diatonic chord as a temporary tonic. Mastering their use is a key step in composing bass lines and realizing four-part textures that reflect the richness of the common practice period.
What You Should Be able to Do
Identify secondary dominant chords in a musical score by their chromatic alterations.
Provide a Roman numeral analysis for a progression containing secondary dominant chords.
Compose a stylistically appropriate bass line for a given soprano melody that implies the use of secondary dominants.
Realize a four-part texture from a figured bass or Roman numeral progression that includes secondary dominants, following standard voice-leading procedures.
Spell any common secondary dominant chord in a given key.
Key Concepts & Analysis
Defining Secondary Dominants and Tonicization
In diatonic harmony, the dominant chord (V) has a strong tendency to resolve to the tonic (I). This V–I relationship is the bedrock of tonal music. A secondary dominant is a chord that borrows this powerful function to create a similar relationship with a chord other than the tonic.
For example, in C major, the dominant is G major (V) and it resolves to C major (I). The dominant of the dominant (V of V) would be a D major chord (V/V), which has a strong pull to the G major chord (V).
This process of making a non-tonic chord sound like a temporary tonic is called tonicization. The secondary dominant "tonicizes" the chord it resolves to. It is a fleeting effect, distinct from modulation, which involves a more permanent change of key.
Voice-Leading with Secondary Dominants
The most important principle to remember is that secondary dominant chords behave just like primary dominant chords. All the voice-leading rules you have learned for V and V7 chords apply directly to chords like V/V, V/vi, or V/IV.
Tendency Tone Resolution
Dominant-function chords contain tendency tones—notes that have a strong melodic pull to resolve in a specific direction. Secondary dominants introduce a new, temporary tendency tone.
The Temporary Leading Tone: The defining chromatic pitch of a secondary dominant is the one that acts as a leading tone to the root of the chord being tonicized. This temporary leading tone is always a half step below the root of the target chord and must resolve up by half step. For instance, in a V/V chord in C major (a D major triad), the F# is the temporary leading tone to G. This F# must resolve upward to G in the following chord. This melodic pattern, often seen as resolving to , is a primary indicator of a V/V chord.
The Chordal Seventh: If the secondary dominant is a seventh chord (e.g., V7/V), its seventh must resolve down by step, just like the seventh of a primary V7 chord. In C major, a V7/V chord is D–F#–A–C. The chordal seventh is C (), which must resolve down by step to B () in the subsequent G major chord.
Doubling and Spacing
The rules for doubling in secondary dominants are identical to those for primary dominants.
Root Position Triads (V/x): Double the root of the chord. Never double the temporary leading tone, as this would result in parallel octaves when it resolves.
Root Position Seventh Chords (V7/x): The chord is typically complete with a root, third, fifth, and seventh. If a note must be omitted for smoother voice leading, it is almost always the fifth. In this case, the root is usually doubled.
Inversions: The same rules of figured bass and doubling apply. For example, in a first inversion secondary dominant (V6/5/x), avoid doubling the temporary leading tone.
Avoiding Parallels
The introduction of chromaticism does not suspend the prohibition of parallel perfect fifths and parallel perfect octaves between any two voices. Careful attention to the resolution of tendency tones will often help you avoid these errors, but you must always check your work. The strong, directed motion of secondary dominants can sometimes create situations where parallels are more likely if voice leading is not handled carefully.
Data & Organization Tools
The following table shows the most common secondary dominants in a major key, the temporary leading tone they create, and their chord of resolution.
| Secondary Dominant | Chord in C major | Temporary Leading Tone | Resolves to |
|---|---|---|---|
| V/ii | A major (A–C#–E) | C# (as ) | ii (d minor) |
| V/iii | B major (B–D#–F#) | D# (as ) | iii (e minor) |
| V/IV | C major (C–E–G) | E (as , already diatonic) | IV (F major) |
| V/V | D major (D–F#–A) | F# (as ) | V (G major) |
| V/vi | E major (E–G#–B) | G# (as ) | vi (a minor) |
Note: V/IV is the same chord as the tonic (I). It functions as a secondary dominant due to its placement directly before the IV chord.
Evidence Bank
Secondary Dominant: A major or dominant seventh chord whose root is the dominant of a diatonic chord other than the tonic. It is analyzed as V/x, where "x" is the chord being tonicized.
Tonicization: The process of making a diatonic chord sound like a temporary tonic by preceding it with its dominant.
Temporary Leading Tone: The chromatically raised third of a secondary dominant chord, which resolves up by half step to the root of the tonicized chord.
Chordal Seventh Resolution: The rule stating that the seventh of any dominant seventh chord (primary or secondary) must resolve down by step in the following chord.
The to Pattern: A common melodic gesture, especially in the bass or soprano, that strongly implies the use of a V/V chord to tonicize the dominant.
V/V (V of V): The most frequently used secondary dominant. It tonicizes the dominant chord, often strengthening a half or authentic cadence.
V/vi (V of vi): A common secondary dominant used to tonicize the submediant chord, often initiating a move toward the predominant area of a phrase.
Skill Snapshots
Rule: The temporary leading tone resolves up by half step.
Effect: This resolution is the primary reason secondary dominants create such a strong pull toward their chord of resolution, effectively "pointing" to the next harmony. For example, in C major, the F# in a V/V chord creates a powerful melodic drive to the G in the V chord.
Rule: The chordal seventh of a secondary dominant resolves down by step.
Effect: This maintains smooth voice leading and properly resolves the dissonance inherent in a seventh chord. In a V7/vi chord in C major (E7), the D must resolve down to C# (in an A major chord) or C (in an a minor chord).
Rule: Never double the temporary leading tone.
Effect: Since the leading tone has a mandatory resolution, doubling it would force parallel octaves, which violates the principle of voice independence. Doubling the root is the safest and most standard practice.
Common Misconceptions & Clarifications
Confusing Tonicization with Modulation: Tonicization is a brief, temporary emphasis on a new chord. Modulation is a more substantial shift to a new key center, often confirmed by a cadence.
Incorrectly Spelling the Chord: Secondary dominants are almost always major triads or dominant seventh chords. Ensure the third of the chord is raised to create the leading-tone relationship to the next chord's root (e.g., V/V in C major is D–F#–A, not d minor).
Forgetting to Resolve Tendency Tones: The temporary leading tone and the chordal seventh have mandatory resolutions. Forgetting to resolve them correctly is the most common voice-leading error when writing secondary dominants.
Applying a Secondary Dominant to a Diminished Triad: In major and minor keys, the leading-tone triad (vii°) is not tonicized with a secondary dominant because a stable tonic must be a major or minor triad.
Summary
Secondary dominant chords are chromatically altered chords that apply the function of the dominant to a diatonic chord other than the tonic. This process, known as tonicization, adds harmonic depth and directional energy to a progression. When part-writing, all standard voice-leading rules for dominant chords must be followed. This includes the mandatory upward resolution of the temporary leading tone and the downward stepwise resolution of the chordal seventh. Recognizing the melodic patterns these resolutions create, such as resolving to , is essential for both analysis and for composing bass lines that imply a richer harmonic vocabulary.