Example 5 IDIOMATIC HARMONISATION IN four PARTS I IV V7 I PROGRESSION
Let’s see how a C-F-G7-C (I IV V7 I) sequence might look on the guitar. The first example shows the bottom four notes of a barre-chord. However, this violates several of our principles: the top two voices drop below their acceptable limit (so they’re 2 xxxxxxxxxx unsingable), the leaps are large, and in the same direction for the last three chords. Plus two voices move in the same direction in octaves (and 5ths), which sabotages their independence. The leading tone in the third chord is not resolved by the same voice, and the subdominant resolves to the mediant in a different voice and octave, making it musically illogical. Bar 2 shows the same sequence, but rendered more classically. Each voice is in its range, with a larger interval from Bass to Tenor than between other voices. Voices move minimally and sound independent. Tendency tones resolve as expected. Sing each one and you can see how the sequence comprises four simple and singable lines.