I've composed the following figured bass example:
It modulates from E to F and therefore needs several chromatic alterations. But my question is on the final beat of the third measure: if I want a B♭-minor chord here, is this the correct figured bass? As I see it, there are at least three possibilities for how to handle this chord:
- Write it as I have; the ♮5 lowers F♯ to F♮ and the ♭♭3 lowers the D♯ to D♭.
- Use a system where the figured bass shows the literal accidentals, not the adjustments from the key signature; in this system, ♮5 would give me F♮ and ♭3 would be enough to suggest D♭.
- Use ♮♭3 to indicate first a change from the key signature's D♯ to D♮ and then a move from D♮ to D♭.
What would be the correct approach here? Ideally I would have a citation from a published figured bass manual (perhaps Heinichen?).
I've never seen a double accidental in a published figured bass before, likely because that repertoire doesn't often get this chromatic. As such, I'm uncertain how best to notate this.