[Smt-talk] Nature and Labeling of the Cadential Six-Four

[Ninov, Dimitar N]

I would like to support what Dmitri Tymoczko about functional arrangements and the nature of the cadential six-four. 

In the Kostka/Payne's book you will see a graph with arrows and turns which is supposed to tell us which chord follows which. This graph is quite incomplete (even typically incomplete) and because of that it is occasionally misleading. 

Thus students are told that III connects very well to VI, but nobody mentions that VI-III is just as good. Students are told that VI does not connect I, but their teachers fail to add that VI to I6 is an excellent connection because of the motion in the bass (as Dmitri mentioned this). Do these teachers know this?

II6 connects perfectly not only to I6/4 (actually, the cases in classical music of II6 to I6/4 may be more than IV to I6/4; we cannot count them anyway) but also to I, in a plagal relationship.

III connects V4/3 perfectly, and this device is used in modulations; when your common chord happens to be III in the new key, V4/3 makes an excellent modulating chord to fully enter the new key.

But the worst thing of all is that the tests in such books are designed in such a manner that they do not give you room or felxibility to point out some of the situations above! As a result, teachers who go by the book will take points off for any answer which is not fully compatible with that chart! A terrible example of thinking in a box! Clever teachers will devise their own tests on that topic.

Also, many less common progressions do a good job such as V between two subdominants, i-v6-VI; i-v6-iv6 and others. If a skillful person knows how to voice-lead, any chord could connect any. In the beginning, however, our students must move along the typical situations, but even those are not comprehensively examined in Kostka/Payne and many other books.

Until things open beyond the common practice period and allow Prokofiev to offer us an amazing cadence substitute for I-IV-V-I. In his Romeo and Juliette we can observe an example of I - flat VI - major III - I with a melodic contour of 1-7-1. In the expanded tonality of the XX century, we can build a major and minor triad on each chromatic scale degree and still subordinate all of these chords to the tonic of C, for example.
 
As for the I6/4 nature, yes - this is as special chord, a unique sonority! It is a chord in its own right!

Best wishes,

Dimitar