I'm working on taking some chorales and their soprano lines out of Bach, and making my own harmonizations/compositions — somewhat more elaborate ones than the typical, straight quarter note exercise.
I came up with this for the third phrase of a chorale from the St. John Passion:
(BWV 245.3, ver. 1: http://www.bach-chorales.com/BWV0245_3.htm. Haven't looked much at what the great man himself did with it yet; leaving that for last is part of the fun.)
Now, I'm kind of wedded to the stately, descending/ascending-by-step-progression eighth note figure going on in the bass, over the last and the first half of bars two and three, respectively. Only I'm somewhat troubled by the fact that the F taken by the bass here — bass goes G to F on the fourth beat of the first full measure — happens to be the seventh of the prevailing chord (tonic, G minor), unresolved, even if I only want it to be an "escape tone". How unorthodox would this be? Say, is it liable to upset college professors everywhere, and also not find any equivalent in a catalogue of "things Bach sometimes did anyway"? (Or only the first?)
I suppose I could emphasize it as a non-harmonic tone by sharpening the F, but then there's an unresolved leading tone.
There's an underlying question here, then, of whether sevenths of chords, particularly non-dominant chords, "have" to be sevenths (with their usual requirements for downward resolution), even if you have a plan for treating them differently — as this relates to this historical style in particular.
As the line stands, I like how the figure is corroborated by sequence right afterwards — I guess that could help.