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§ Partimento Chord Progression Theory
created 2024-11-30
- consider the ones in the key of C minor.
- The chord that corresponds to
Ab is given as D F# C. - Luisa's insight: Consider the 5th, which is
Gm. It's 7th scale degree is F#. - Luisa's instruction: Think of this the other way round: Note that we see an
F#, which we recognize as the 7th scale degree of the Gminor scale. - Now, what is
Ab D F# C in Gm? That's the question we try to answer. - This is a french sixth or augmented sixth
- We start with
Ab, which is the sixth in the scale degree. - We throw in the third, which is
C. - We then add build the augmented sixth interval with
Ab as the lower pitch, giving us F#. - Now, it is popular wisdom that a sixth comes with a fourth (the
D wrt Ab), with the idea that we resolve the 1 3 4 6 → 1 3 5. - However, the actual resolution in the book is more interesting: We have
Ab D F# C → G D G B, where the D does not "actually move", the F# → G, and the C → B, and Ab → G. Note that this is pretty genius, because it only moves by a single semitone. - The
Ab ⇒ G changes the chord, while the other two notes resolve.
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