I’m in the process of catching up.
The handouts from Dr. Oravitz should be the most helpful thing you have on the topic of sequences. I’ve posted them in my iLocker 112 folder (Common harmonic sequences, sequence repertoire) if you need to get another copy.
A few words about sequences to reinforce some key points.
Know the common sequence types by root movements.
- descending fifth
- Pachebel (descending fourth, ascending second, resulting in an overall descending third)
- 5 -6 exchange
- descending second 6 – 3
The descending second with 6 – 3 chords is the only sequence that is usually comprised of a one-harmony segment.
The Pachebel sequence is obviously a two-harmony segment, since the driving movement of the sequence is to descend by thirds. The third descent is why I refer to it as a descending fourth/ascending second sequence, rather than an ascending fifth/ascending second. The root movement is the same, but the latter way of describing it suggests the sequence ascends by sixths.
The descending fifth sequence is less obviously a two-harmony segment, but usually the melodic segment will traverse two harmonies to emphasize a descending second movement. For example, starting on i in c minor will give root movements of C – F, Bb – Eb, Ab – D, most likely moving to G (V) and breaking the sequence. Notice the descent comprising the first root of each pair of harmonies: C – Bb – Ab, followed by G. Creating a two-harmony segment allows for a melodic sequence with each segment a second below the previous one.
A descending fifth sequence using all seventh chords requires an alternation between complete and incomplete seventh chords. Upper voices move either by common tone or step-wise descent, with the root doubled in the incomplete seventh chords.
Inversions are always possible in a sequence. Using inversions doesn’t change the basic sequence type (classified by root movement, not bass movement), but it may change the voice leading. With descending fifth progressions of seventh chords, alternating between a root position seventh and a second inversion seventh (4 – 3 chord) allows for every chord to be complete AND have EVERY voice move either by common tone or descending second.
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