Definition of the Window
On the series of fifths, a form of "Window",
through which one sees 7 adjacent members,
will enable us to select any desired diatonic system (key),
having from 0 to 7 sharp or flat notes.
When the series of fifths is disposed vertically,
the flat notes are below and
the sharp notes are above in the series.
We will, for greater simplicity, always use the Window
containing the 7 natural notes (F, C, G, D, A, E, B).
All of the concepts proposed would also apply
to any other diatonic system (any other key),
by simply moving the Window.
We will start by inserting the MEDIAN (major or minor)
in the center of each FRAME:
G in the FRAME E-B,
C in the FRAME A-E,
F in the FRAME D-A, and
B in the FRAME G-D,
E in the FRAME C-G,
A in the FRAME F-C.
Disposition of triads
We now have 3 minor triads in the top of the Window
(E-G-B, A-C-E, D-F-A)
and 3 major triads in the bottom
(G-B-D, C-E,G, F-A-C).
Definition of triad mode
A triad is minor when it has
a major third (4 semitones) placed above, and
a minor third (3 semitones) placed below.
A triad is major when it has
a major third (4 semitones) placed below, and
and a minor third (3 semitones) placed above.
In each group of 3 triads (the minor group and the major group)
the TONIC Chord (I) is in the center
A-C-E, the Minor TONIC and C-E-G, the Major TONIC.
Definition of TONIC
The TONIC chord is the one around which all harmony is built.
It is the chord of final rest on which a piece ends.