AP Music Theory
Unit 7: Harmony and Voice Leading IV: Secondary Function
4 topics to cover in this unit
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Secondary Dominant Chords
Alright music theorists, get ready to add some serious spice to your harmony! Secondary dominant chords are like little mini-V7 chords that temporarily point to a diatonic chord other than the tonic. Think of them as 'borrowing' a dominant function from another key, giving us a momentary pull towards a new tonal center without fully modulating. They create excitement and drive, making the music feel like it's taking a quick detour before returning home (or moving on!).
- Confusing secondary dominants with actual modulations – remember, it's just a temporary 'tonicization'!
- Incorrectly resolving the leading tone or the seventh of the chord, leading to voice-leading errors.
- Misidentifying the target chord (e.g., calling V/vi 'V/VI' or 'V/ii').
- Forgetting the accidental that creates the temporary leading tone (e.g., F# in C major for V/ii).
Secondary Leading-Tone Chords
If secondary dominants are the cool older sibling, secondary leading-tone chords are their equally cool, but perhaps a bit more mysterious, younger sibling! These are diminished triads (vii°/X) or half-diminished seventh chords (viiø7/X) that function as leading-tone chords to a diatonic chord other than the tonic. They create a similar pulling effect as secondary dominants but with that characteristic diminished sound, adding tension and chromaticism that resolves beautifully to their temporary tonic.
- Confusing diminished triads with half-diminished or fully-diminished seventh chords, especially in dictation.
- Incorrectly resolving the leading tone or the diminished fifth/seventh, leading to parallel octaves or fifths.
- Not recognizing the diatonic chord that the secondary leading-tone chord is 'pointing' to.
- Forgetting the multiple accidentals often required for these chords.
Tonicization
Okay, let's zoom out a bit! Tonicization is the *process* of temporarily making a non-tonic chord sound like a tonic. It's the big idea behind both secondary dominants and secondary leading-tone chords. Imagine you're driving on a highway, and you take a quick exit to grab a coffee, but then you immediately get back on the same highway. You briefly visited a new place, but you didn't change your destination. That's tonicization – a fleeting visit to a new tonal center, often marked by the presence of an applied chord followed by its temporary tonic.
- Calling tonicization 'modulation' – these are distinct concepts! Tonicization is temporary, modulation is more permanent.
- Not recognizing that the 'temporary tonic' is still diatonic to the original key.
- Missing the brief nature of the tonicization, expecting a full key change.
Modulations to Closely Related Keys
Alright, now we're actually changing highways! Modulation is a more permanent shift from one key to another. But we're not just jumping anywhere; we're talking about 'closely related keys.' These are keys that share a lot of common chords and have key signatures that differ by only one sharp or flat. Think of it as moving from your house to a friend's house in the same neighborhood – still familiar, but a definite change of address. The most common way to do this is with a 'pivot chord,' a chord that belongs to *both* the old key and the new key, acting as a harmonic bridge!
- Confusing tonicization with modulation – again, one is temporary, the other is more permanent.
- Misidentifying closely related keys (e.g., thinking parallel major/minor are closely related, which they are not in this context).
- Struggling to find an appropriate pivot chord that truly functions in both keys.
- Not recognizing the change in key signature or tonal center after the modulation.
Key Terms
Key Concepts
- Secondary dominants are major triads or dominant seventh chords built on a root that is a perfect fifth above their temporary tonic.
- They create a strong leading-tone effect to their target chord, temporarily making that chord feel like a tonic.
- Correct voice leading involves resolving the tendency tones (leading tone up, 7th down) to the target chord.
- Secondary leading-tone chords are built on the leading tone of their temporary tonic.
- They provide a strong tendency to resolve to their target chord, often creating a sense of heightened drama.
- Proper voice leading is crucial, especially with the two tritones present in a diminished seventh chord – resolve them carefully!
- Tonicization is a temporary shift of tonal emphasis, not a permanent change of key.
- It is achieved through the use of secondary (applied) dominant or leading-tone chords.
- The effect of tonicization is to add color, variety, and harmonic interest to a passage without disrupting the overall key.
- Closely related keys are keys whose tonic triads are diatonic to the original key, or whose key signatures differ by no more than one accidental.
- Pivot chord modulation uses a chord that functions diatonically in both the original key and the new key, smoothing the transition.
- Modulation creates larger-scale harmonic movement and is often used to delineate musical forms.
Cross-Unit Connections
- Unit 1: Fundamentals of Music Theory (Key signatures, intervals, triads, and seventh chords are the building blocks for all secondary functions and modulations).
- Unit 3: Harmony and Voice Leading I (Understanding diatonic harmony, root movement, and basic voice leading is essential before introducing chromatic alterations).
- Unit 5: Harmony and Voice Leading III (Knowledge of dominant seventh chords and leading-tone seventh chords is crucial for understanding their secondary applications).
- Unit 8: Harmony and Voice Leading V (This unit lays the foundation for more advanced chromatic harmony, including modulations to remote keys and more complex applied chords).
- Unit 9: Form and Analysis (Modulation is a fundamental tool for creating musical form, especially in larger structures like sonata form, where movements between closely related keys are common).