Make practice a part of the living day
2008, May 26
Ninth chord
A revision of the analysis of the cross relation of April 22, 2008
Here is the original post with sound files of the parts.
A dominant seventh chord is built of four scale degrees: the fifth as the root, the seventh scale degree as the third of the chord, the second scale degree as the fifth of the chord and the fourth scale degree as the seventh of the chord. The fourth scale degree resolves to the third scale degree, thus acting as a passing tone.
Listen to the progression: i V V7 i:
Here is a discussion of chords and seventh chords.
The dominant ninth chord adds the sixth scale degree as the ninth of the chord. In four part writing, one note must be omitted, usually the fifth of the chord, the second scale degree.
Pertaining to the omission of the root of chords, R.O. Morris says: "It seems to the author…that a chord from which the root has to be omitted ceases ipso facto to be that chord at all, and that no suport should be given to so paradoxical a method of classification."
So I have revised my speculation about the analysis of the phrase in BWV 114.7 with the cross relation; I have changed it to the analysis shown below. I think this unnecessarily complex, cumbersome and academic analysis highlights the fact that Bach wrote chiefly with melody in mind and was not concerned with the mental anguish of his students three hundred years later.
Home page for Robert Frank's Theory on the Web.
R.O. Morris, The Oxford Harmony Volume One, Oxford University Press, 1946.
ISBN 0 19 321491 1, p130
