1.3 - A practice of analysis in the tonal harmonic discourse from Bach to Wagner ||
A) FORMULAS - 1. Definition of a formula :: 2. Presentation of the little catalogue of harmonic vocabulary :: 3. User's guide to the little catalogue and various instructions :: 4. Examples illustrating the little catalogue (motifs: 1, 2, 3, 4, 5, 6a, 6b, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, motifs in combination)
B) SEQUENCES - 1. Definition of a harmonic sequence :: 2. Classifying sequences :: 3. Melodic formulations: characteristic motifs :: 4. The tonal nature of the harmonic sequence :: 5.The tripartite structure of the harmonic sequence :: 6. A modulating sequence or not? :: 7. Diversification of harmonic content :: 8. The harmonic sequence as a place of subversion :: 9. Conclusion

5. THE TRIPARTITE STRUCTURE OF THE HARMONIC SEQUENCE

1. The model.
Sometimes the model is repeated (see examples 393, 415 and 500).

2. One or several reproductions of the model.
When there are several reproductions of the model, the last of them may be incomplete as we have already observed.

3. The closing formula.
Unless it introduces plagal content (for example, VI - IV - I, or other plagal formulas as shown following figure 11), the closing formula generally corresponds to one or another of the formulas from the little catalogue and therefore proves easily identifiable due to the characteristic motif involved. However, the role of establishing a key is sometimes filled by the arrival of another sequence which may or may not share the same model. In the latter case, we observe a sort of mixed sequence structure that overlaps two different types. Let us also emphasize that the closing formula, unless it corresponds to another sequence, takes place outside the process of imitation and begins with the final chord of the last reproduction. In fact, the closing formula conforms to a procedure of tonal analysis which we adopt systematically and which can be stated as follows:

 

Example 418 : P.I. Tchaikovsky : Symphony no 4, op. 36, III, Trio (mm 170-176)
a) Type 4 sequence, b) type 8 sequence serving as a closing formula

Example 419 : L.V. Beethoven : String quartet, op. 18, no 1, IV (mm 301-307)
Type 2 sequence

Example 420 : F Sor : Etude for guitar, op. 6, no 8 (mm 1-10)
a) Type 9 sequence and b) type 1 sequence serving as a closing formula

On the other hand, a sequence deprived of its closing formula may find its tonal affiliation determined by the context:

Example 421 : F. Chopin : Etude, op. 10, no 3 (mm 14-21)
a) Type 8 sequence and b) type 4 sequence

In this last example, let us note that the type 4 sequence articulated in this manner without a closing formula still holds the power to estalish a key.  This brings up the topic of the structural effect of tonal conditioning that tends to lead the listener, wherever possible, to cause the end of a harmonic event to coincide with a tonic function due to the expectation of a conclusion. Moreover, this sequence, even isolated from all context, is spontaneously heard as I - V - VI - III - IV - I, thereby joining a long tradition of use already evident in the 16th century.

Example 422 : J. Dowland : Now, O now I needs must part (mm 1-2)
Type 4 sequence

6. A MODULATING SEQUENCE OR NOT?