Four part writing: How to voice diminished 7th chords?

Question

I am currently doing part writing, and have come into a bit of a conundrum. I want to use a sharp 4 dim 7 (Fsharpdim7), to link up my IV chord (FM) to my V7 chord (G7).

I know that 7ths should usually be prepared in the previous chord, or approached by leap if this is not possible. However, when I adhere to these rules in this case (particularly approaching the dim7th by leap), the end product sounds terrible. So, in the pictured example, I have tried to move the voices as little as possible, only moving by step and maintaining all common notes. When I play this as all 7th chords (FM7, Fsharpdim7, G7) it sounds great, but here my first chord is an FM triad, so we move from F (doubled root) to Eflat (dim7th) then to F (7th of G7). It doesn't sound as good, but is this none-the-less the correct/ best way of voicing this progression? Is there anything else I should know about voicing these passing dim7th chords?

Answer 1

You're correct that these sevenths should be prepared (by step or by common tone) in the same voice! But also remember that we need to resolve those sevenths down by step, too.

Thus the E♭ in your middle chord, since it's the chordal seventh, needs to resolve down to the D of the next chord.

Regarding preparing the seventh of the G7 chord, there are a few options:

1. One is to acknowledge that it's mostly impossible to prepare this by step, since there's no G in the prior chord. Thus you could resolve to a V triad, and then a G (probably in the soprano, coming from the A) can quickly move to F to turn this V triad into a V7.
2. Or you could go the full Beethoven route and have the F♯ in the bass slide down to F, making this V7 a V42. But if this is for a theory class, maybe wait to do this; your teacher probably hasn't talked about this yet.

My preferred solution would be #1 above: when you resolve your alto E♭ to D, you'll see that it's likely best for your tenor C to resolve down to B instead of doubling that D. And since we can't double the leading tone (B), let's also move that soprano down to G before moving it to F to make the V7.

Answer 2

Rather than think of the diminished chord as #IV, consider it as vii^o/V. In that case, scale degree 4 (relative to V: i.e., C is 4 of G) should resolve downward to B. That allows the Eb (chordal 7th) to also resolve downward, to D.

From there you have a choice. If you want a root position V7 chord, then the soprano A moves down to F (you could have the soprano play G either as a passing note or as a resolution before continuing to F). Alternatively, the bass moves to F and the soprano moves to G.

Answer 3

I know this isn't exactly what you asked, but Eddie Lang would often move from the IV chord to a diminished chord a whole tone below the root of the IV, and the resolved up to the first inversion of the tonic skipping the V chord altogether, which is a half step above that.

Sorry, I am not a pro at SATB voice leading but I tried my best.

You can hear it here

I set the video to start on measure 20 of this song.