5b: Seventh Chord Voice-Go-Round

Once you understand from the theory page the mechanical construction of the diatonic modes as maximally even subsets of the regular 12-tone system, you may apply the same idea to the construction of the 28 inversions of the seven diatonic seventh chords. The lower movie is more suggestive with regard to this analogy, while the upper movie shows, how to play the example on the SolFa Mode-Go-Round. Basically - on the basis of the seven scale degrees - you may think of a rotating square, whose vertices are moved one by one rather than simultanuously. In a more refined way - on the basis of the 28 tone roles (four tone roles for each scale degree) - you may literally think of a rotating square.

Think of the inversions of seventh chords as 4-tone modes in a world with seven (equally distributed) steps.

Instead of seven Modes with seven tones (Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian) one has four modes with four tones:

Root position (7 Chord)
First Inversion (6/5 Chord)
Second Inversion (4/3 Chord)
Third Inversion (4/2 Chord)

What would be the intrinsic "tone syllables" in such a world of seventh chord inversions? Help: Remember that the syllables do, re, mi, fa, so, la, ti refer to unique neighborhoods in the step interval pattern. Do is preceded from below by a half step and it followed above by two steps and one half step. Re is preceded from below by a full step and it followed above by a step, a half step, and again a step, etc.

Thus one may say that the tone roles in the seventh chord: prime, third, fifth and seventh behave analogously to the Solmization syllables (see the background image of the lower video):

The prime is always preceded by a second from below and followed by two thirds.
The third is always preceded by a third from below and followed by two thirds.
The fifth is always preceded by a third from below and followed by a third and a second.
The seventh is always preceded by a third from below and followed by a second and a third.

Each voice cycles four times through the syllables do - ti - la - so - fa - mi - re and cycles seven times through the tone roles prime - third - fifth - seventh seven times. The entire cycle completes after 28 tones in each voice.

In addition to just playing the "Voice-Go-Round" you may pick one of the four voices and sing the tone roles, while playing the other two voices on the instrument.

Note: It is not by accident, that the wording of this tutorial is stricly analogous to Tutorial 5a. Note, however, the subtlety in the relation between direction of the syllables and the direction of the tone roles. Here ascending tones roles correspond to descending syllables.

Doing two progressions at once leads to a kind of "ambling" square-walk ("Camel walk") around the circle. The result is a diatonic fifth-fall sequence (see 3rd video). This pattern will occur again in Tutorial 5a

NB: The video above was made from an Earlier Version of the App.