Harmonizing a Melody with Triads in Inversion
Now that we understand harmonizing a melody with root position chords, we can expand our palate and add on chords in first and second inversion. Inversions will allow us to create more interest and variety in the music as well as a smoother, more singable bass line. Part writing in all inversions allows us to put combine our knowledge of part writing for root position, first and second inversion chords. The basic steps to harmonizing a melody are the same as those used for root position chords, but we look for for opportunities to use second inversion chords as well as smooth out our progression and add flexibility to our chord choices using first inversion chords.
Steps to harmonizing a melody
- Identify the key.
- Write down the chords contained in the key in root position.
- Write in the scale degrees in the soprano voice.
- List chord possibilities under each note in the soprano.
- Identify the melodic phrase structure/cadence points and determine harmonic rhythm.
- Eliminate any chords that cannot be used (either from motion in the soprano, connections between chords, or from choices made in phrasing/harmonic rhythm/cadences). When part writing with first inversion chords, we can allow using iii and vi, but need be very careful of when and how they are used to prolong progressions and connect chords. We will still focus primarily on Progression, Repetition, and Tonic motions between chords.
- Look for places where you can insert a 6/4 chord
- cadential 6/4: most common 6/4 chord, so it’s a good option to look for first
- Used only at a cadence directly before a V chord.
- Need a soprano line that can support tonic followed dominant harmony.
- The cad 6/4 must be metrically stronger than the V that follows.
- Passing 6/4:
- The soprano motion can be sustained between the 3 chords, can move stepwise in contrary motion to the bass between the 3 chords, or use lower neighbor motion between the 3 chords.
- Make sure the passing 6/4 is connecting 2 chords of the same category (like I and I6).
- The most common passing 6/4 chords are I6/4 between V chords and V6/4 between I chords.
- Do not use this chord at a cadence.
- Pedal 6/4:
- The soprano motion can be sustained between the 3 chords or will use upper neighbor motion between 3 chords.
- Pedal 6/4 chords usually connect 2 of the same chords, or chords with the same function.
- The most common pedal 6/4 chords are I6/4 between IV chords and IV 6/4 between I chords.
- Do not use this chord at a cadence.
- Choose a chord progression, looking for places to insert chords in first inversion to make motion smoother (exception: we want the leap from V to I at a final cadence). Remember that you cannot use a 6/4 chord unless it is one of the types of 6/4 chords (even if trying to avoid part writing errors).
- Write in the bass voice for your chosen chord progression and check it for errors against the soprano voice.
- Part-write the inner voices (make good choices in connecting chords melodically). Check your answers for errors.
Summary of harmonizing a melody using chords in inversion
- Follow the steps outlined for harmonizing a melody using chords in inversions.
- Remember that while first inversion chords can be substituted for root position chords, second inversion chords must be one of the types of second inversion chord possible and be supported by the notes in the harmony and melody. Double the bass in second inversion chords and follow correct part writing procedures. Since second inversion chords have the most specific requirements for motion and chord choices supported by the scale degrees, make sure to look for places to insert second inversion chords before selecting the rest of the chord progression.
- If you create errors, you can change the bass octave (if possible), change the chord inversion, or select a different chord.
Proceed to the theory exercise for a guided example on harmonizing a melody with chords in inversions.