In Unit 11, we discussed how repeated patterns and sequences in voice-leading can override standard voice-leading practices. One such example was how a sequence of seventh chords can require “incorrectly” resolved chordal thirds and sevenths. To demonstrate this, harmonize the excerpt below paying attention to the chordal resolutions between the ii7 and V4/3 chords. Which voices must use non-standard resolutions to accommodate the progression?
In order to use complete chords, the chordal third of the ii7 chord must remain static to become the chordal seventh of the V7 like so:
Because secondary dominant chords are so closely related to diatonic circle-of-fifths progressions, you may apply the same principle to repeated series of secondary dominant seventh chords. Try the same voice-leading on the following example. What changes? How does this affect accidentals within the bar.
You may keep the same resolutions that you used in the diatonic example above–the chordal third of the first chord becomes the chordal seventh of the following chord. The static motion in the alto voice is altered though, because you must resolve down by half-step now that the chordal third has been raised.
Unsurprisingly, this concept can be extended to encompass the entirety of the diatonic circle-of-fifths progression. Begin by harmonizing the following standard progression.
This progression is nearly identical to the progression we used in Unit 14 to introduce secondary dominant chords by altering the ii chord. We then altered the vi chord from the same progression in Unit 15a in order to demonstrate tonicization of chords other than V. Because the voice-leading is so similar, secondary dominant functions can lead into each other creating series of secondary dominant chords. In the example above, alter your voicing of the ii7 chord to create a V7/V chord and alter the vi7 chord to create a V7/ii creating a progression of:
I - V7/ii - V7/V - V7 - I
This progression now simply extends your seventh chord resolutions from the examples above, although the fixed soprano line forces you to use an incomplete chord on your V7/ii.
Therefore, secondary dominant chords can be substituted freely within a circle-of-fifths progression.
There is a less common resolution of secondary dominant chords that relies on the voice-leading from a deceptive cadence. Analyze the following example, and you will notice that at first glance, the progression does not follow our established progressions between the second and third chords. To understand this, you must think in the borrowed key. What key would this chromatic chord normally tonicize? If you were in that key, how would label the progression between these two chords? It is very helpful to use leadsheet symbols here.
In this progression, the E7 chord is likely to function as the dominant in the key of A major/minor. But instead of resolving to an A minor chord–the diatonic vi of the current key of C major–it resolves to an F major triad. At first this seems almost nonsensical, but if you examine the tonicization in the key of A minor, you will realize that this is a common progression in that key–a deceptive progression of V7 to vi. In labeling this in our secondary key, you do not need to label anything further, but feel free to use the abbreviation of “dec” in parentheses between the two chords if you would like to make a note of this uncommon use of secondary dominants.
In short, if you find a root-position secondary dominant chord that does not resolve to its normally tonicized chord, check to see if it instead resolves to a diatonic chord with a root that is step (M2/m2) above the root of the secondary dominant. If so, this is a deceptive resolution in a secondary key, so you should still label the secondary dominant in the secondary key.
Remember that all deceptive progressions create difficult voice leading in four-part harmony, particularly if both chords are triads. Please refer to the voice-leading guidelines for this progression in Unit 11 if you would like to review.