Harmonizing melodies with modulations to closely related keys involves a bit of long-range planning. Since analyzing the entire melody with scale degrees in the original key won’t help with modulations, you need to start a little more schematically.
- Start by examining the melody at cadences, specifically looking for the two-note melodic cadence. Figure out the different possible keys and harmonic cadences that would support the melodic cadence.
- Examine the melody immediately following the cadence to see what key area(s) it could support.
- Sketch a bass line and harmonic progression with Roman numerals at each cadence (two chords for the cadence itself, plus maybe one chord before it). I switched 2 and 3 in class.
- Focus on how you get from your key at the beginning of the phrase to the new key at the cadence. Consider what harmonies are common to the two key areas, which can help you find a pivot chord for modulation. Remember that chromatic modulations are possible, but that they usually happen early in the phrase to allow for a strong cadence to come afterwards to reinforce the change. Pivot chord modulations can occur anywhere in the phrase.