In this first phrase of a part writing exercise I have been given ( "Harmony and Voice leading 5th edition") a figured Bass and the few soprano tones marked with red dots. I am stuck right at the end where there is an ascending soprano moving in parallel tenths with the Baseline. The very last beat is tricky because if I double the bass and tenor Bb I will not be able to move to the C at the semicadence without a parallel unison or overlaps. If I double the 3rd of the Bbm chord I will have parallel octaves with soprano. Have I made an error in the previous harmonizations to not be able to get past to the cadence? Can anyone give me some alternatives solutions please?
The outer voice move by tenths then contrary motion to an octave on the dominant.
First complete the triadic harmony with
F for root and fifth of chords and
E natural for the third of the
V (which is still incomplete, but that's OK.)
The rest is about what to double and how to avoid forbidden motions. The outer voices and first inner voice are all OK, so we really only need worry about parallel fifths and octaves rather than direct fifths and octaves.
Going by the rule of thumb to double tonal degrees we can try doubling the tonic
F or the dominant
It seems to me the question isn't how to get from
iv, but how to get from
V. With root progression by step you want to move all the upper voice contrary to the bass. When you do that with
V the scale degree
^4 subdominant will go down to the
^2 supertonic (
^1 goes to
^6 goes to
^5.) So, whether the doubled tone is
C, move it to the subdominant then to the supertonic.