Adding Predominant Function IV (iv) and ii (iio) to a Melodic Phrase
In AP Music Theory, understanding harmonic progression and chord functions is essential for writing strong musical phrases. One of the most important functions in tonal music is the predominant function, which prepares the dominant (V or V7) before resolving to the tonic (I).
Two of the most common predominant chords are:
- IV (or iv in minor) – The subdominant chord
- ii (or iio in minor) – The supertonic chord
In this guide, we’ll explore how to effectively incorporate these chords into a melodic phrase while following proper voice-leading rules.
1. What is the Predominant Function?
The predominant function serves as a bridge between the tonic (I) and dominant (V) chords. Its role is to create tension that leads smoothly into the dominant, strengthening the eventual resolution to the tonic.
Common Predominant Chords:
- Major Key: IV, ii
- Minor Key: iv, iio (diminished)
2. Using the IV (or iv) Chord in a Melodic Phrase
The IV chord (subdominant) is a strong predominant chord that adds warmth and stability before moving to V.
Example in C Major:
- Chord Progression: I – IV – V – I
- Melody: C (I) → F (IV) → G (V) → C (I)
Voice Leading Tips:
- The bass line often moves I → IV → V → I (e.g., C → F → G → C).
- The soprano (melody) can use stepwise motion (e.g., C → A → G → C).
- Avoid parallel fifths/octaves when moving from IV to V.
Minor Key (iv):
In minor keys, iv is used instead of IV (e.g., A minor: i – iv – V – i).
3. Using the ii (or iio) Chord in a Melodic Phrase
The ii chord (supertonic) is another strong predominant, often leading to V. In minor, it becomes iio (diminished).
Example in C Major:
- Chord Progression: I – ii – V – I
- Melody: C (I) → D (ii) → G (V) → C (I)
Voice Leading Tips:
- The bass line moves I → ii → V → I (C → D → G → C).
- The soprano can use stepwise or arpeggiated motion (e.g., E → F → G → C).
- In minor keys, iio is diminished, so resolve the leading tone carefully.
Minor Key (iio):
In A minor, the progression would be: i – iio – V – i.
4. Combining IV (iv) and ii (iio) in a Phrase
A more advanced progression alternates between IV and ii before moving to V.
Example in C Major:
- Progression: I – IV – ii – V – I
- Melody: C → F → D → G → C
Voice Leading Considerations:
- Smooth stepwise motion in inner voices.
- Avoid doubling the leading tone in minor keys.
5. Common Mistakes to Avoid
- Parallel Fifths/Octaves: When moving from IV to V or ii to V.
- Improper Resolutions in Minor: The diminished iio must resolve correctly.
- Overusing Predominants: Too many chords before V can weaken the progression.
6. Final Tips for AP Music Theory Success
- Practice Writing Progressions: Use IV, ii, and their minor counterparts.
- Analyze Classical Music: Study Bach chorales for voice-leading examples.
- Check for Errors: Always verify smooth voice leading and proper resolutions.
Conclusion
Mastering the predominant function with IV (iv) and ii (iio) is crucial for strong harmonic progressions in AP Music Theory. By following proper voice-leading rules and experimenting with these chords, you can create more expressive and dynamic musical phrases.
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