Does V42 only resolve to I6 or can it move to V7 forming a stepwise bass?

Question

If the chordal 7th needs to resolve down by step then I understand why V42 should move to I6 but cant chords be expanded and the dissonant 7th in a 7th chord move to another voice for example from the bass of the V42 chord to an upper voice in the root position V7 chord? This will allow stepwise motion from ^4 to ^5 in the bass which sounds nice.

Answer 1

No, this is not frequently done, for a lot of reasons:

• The pattern of scale tone Fa resolving to scale tone Mi is just too strongly-embedded in this style to allow for Fa-Sol in the bass there.

The leading tone always resolves upwards, and likewise it is important to remember that the fourth almost always resolves downwards. The tritone pair of notes resolve outwards towards C and E, and violating that pattern is an easy way to distract from voice independence (generally not desired in counterpoint).

• The pattern of the chordal seventh always resolving downwards is also extremely strong.

The whole idea behind the 3rd inversion dominant is to set up the resolution to the mediant scale degree bass. Any time a dominant seventh chord appears, its seventh should resolve downwards or stay on the same note. This tends to create singable melodies for whichever part resolves the seventh; ignoring this traditional pattern of resolution in the bass risks distracting the audience with an audibly unconventional chord progression.

• The V(4/2) chord is just too unstable, and it's unidiomatic to go from that extreme instability to anything but a resolution.

Typical dominant patterns decrease in stability until they finally resolve. This pattern, on the other hand, starts extremely unstable, then moves to a more stable dominant, then back to the tonic. That's like watching an action movie where the stakes get lowered right before the climax!

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Can this be done? Yes. Make whatever music sounds good to you. But I don't think it happens often in the style suggested by the wording of the question.

Answer 2

4.2 indicates a chord in the third inversion. If we take C majors dominant chord as an example then the seventh of that chord would be an F. Seeing as this would be a chordal seventh it would resolve down to an E. Which conveniently is the I6 chord ( of C Major. )