General Principles of Harmony

Transitions Between Various Types of Harmony

We have discussed various techniques above for solving an important problem: creating clear, audible, and coherent harmonic character. But it is not necessary, or even always desirable, to use just one harmonic technique over a whole piece. Provided the transition is smooth, it can be musically convincing to move from one harmonic technique to another. The main way to achieve this is via common elements. (Persichetti has an excellent discussion of this subject on pp. 271-5.)
 
Of course, some techniques can be more easily linked than others, depending on the degree of common ground between the starting point and the ending point. For example, added notes can easily move into to polyharmony (or vice versa), and intervallic harmony can alternate with cellular harmony using the same interval(s). Certain other techniques are harder to connect, because they have so little in common. For example diatonic modal harmony is not easily transformed into serial harmony.
 
Changes in harmonic technique can be applied within individual phrases or over larger stretches. When making such transitions between sections, that they need stronger emphasis, to make clear to the listener that the change marks an important formal joint.
 
Here is an analysis of changes in harmonic technique within one small piece:
 

 
5a.mp3

 
All of the harmonic transitions here occur through common tones, stepwise voice leading, and clear intervallic associations between successive harmonies. Motivic elements help to hold the piece together as well.