Wednesday, July 19, 2017

Symmetrically Extended (Sym Extended) Major 7th Arpeggios

Before working on this exercise, I recommend you review the previous posts on "3rd Rail Chord Symmetries":

The concept of "Symmetrically Extended Arpeggios" is part of the Fretography Symmetry in which you can think of certain chords or arpeggios as starting with a central interval and extending both up and down equally. In the case of the Major 7th chord, the interval structure is:

Root <maj3rd> 3rd  <min3rd> 5th <maj3rd> 7th

Notice that the intervals themselves form a symmetrical sequnce; two major 3rds around a central minor 3rd. When this 7th chord is extended to the next 3rd above and below the structure is:

Root <min3rd> 3rd <maj3rd> 5th <min3rd> 7th <maj3rd> 9th <min3rd> 11th

In the above diagram the F maj7 chord is shown with the notes D below it and G above it. The D could be thought of as a 13th. So rather than the entire arpeggio being a D minor 11th, we could describe it as a F major 9th/D or a "major 9/13 chord." I prefer "Sym. Extended Maj7th."

As you can see, the symmetry continues as a minor 3rd is added at both ends of the original major 7th chord.  The major 7th is now formally a minor 11th. This chord occurs on the 2nd and 6th degree of any major key. For instance, in the key of C major the two minor 11th chords are D min 11th and A min 11th. The D min 11th contains the F maj7th, the A min 7th contains the C maj 7th. When this sequence is arranged on the fret board across four consecutive strings it forms an "S" shape as shown in the diagrams below. 

These diagrams apply to any key you choose. The Roman numerals indicate the key degrees: 

We will refer to these arpeggios as "Symmetrically Extended Major 7ths" because the central four notes remain the most accessible — as a group — on the fretboard all at once. In the upper four strings, as shown above, the shape is perfectly symmetrical and occurs within the VII zone and the III zone.
Moving to the four middle strings the shape changes to a less symmetrical geometry and aligns in the III zone and VI zone as shown below:
In the four low strings the shape is once again symmetrical, positioned within the VI zone and the II zone as shown below:
In the next post we'll examine ways of combining these forms with each other and with other musical structures.

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