sharp ii dim 7th: How to use?

Question

Still here and working on part-writing. I have used a sharp ii dim7th chord, straight after iihalfdim7- leading to V. Is this actually the right place to put it in terms of chord sequence/harmonic progression? Obviously, as we are in minor, the ii chord is also dissonant, so the progression has to be treated very carefully.

I have voiced the two chords as follows. The key is E minor:

Potential issues:

1.As you can see, in the ii half dim7, I have an augmented 4th between the tenors and alto. This dissonance does not resolve in the next chord, and instead becomes another augmented 4th interval , just half a step up (C-Fsharp, Csharp-F double sharp). Is this acceptable/unavoidable?

2. I have leapt into a dissonance from A to F sharp in the tenor (F sharp being the augmented 4th of the dissonance). Is this also unavoidable? (perhaps a remedy here is to double the E [5th] of the previous chord, allowing a move by step into the dissonance? although this would be unorthodox doubling).

Any help gratefully received!

Thanks

Ed

Answer 1

♯ii°7 is really only used for one of two reasons, and in both cases it will be labeled differently:

1. As a vii°7/iii to tonicize iii. Notice that this really only works in major keys, because in minor the root of ♯ii is enharmonically equivalent to the root of III.

2. As a common-tone diminished seventh (often labeled CT°7) expanding tonic.

Since you're in minor, the second option is really the only viable use of this chord, in which case you will typically go from i to this "♯ii°7" back to i. And since the purpose of the CT°7 is often to keep the common tone in the same voice, this "♯ii°7" will typically be in third inversion so that the bass E stays constant throughout.

For more on the common-tone diminished seventh, see the first half of this answer.

Answer 2

You've discovered one of the tricks that Romantic piano music is based on-- throw layers and layers of dim7 chords one after the other, especially during your flashy crashy-bangy solo sections, and you'll get a dramatic sound that can end up on any key you want.

A fundamental rule in music is that raised tones rise. An augmented F wants to resolve a half-step up: to G#. I'd recommend g# minor, since it's going to be pretty easy to get to B7 and back to e.

One comment as a music teacher: write more NEATLY. Get a thick mechanical pencil (0.5mm is good) with a soft lead. And frame your page properly, because not doing so shows disrespect to the people whom you would like help from.