In 1722 Jean Philippe Rameau wrote his famous "Treatise on Harmony".The second section of this treatise deals with the nature and properties of chords: and on everything which may be used to make music perfect.This whole notion of perfect music is so much nonsense. Just as there is no perfection in life; how can we be expected to produce perfection in music? You see "music theory" is a compilation of hundreds of different perspectives on a single main method of music construction. Almost all forms of music utilize chord progressions.
Chords are made from the scales that are inherent in all the keys. Simple formulas can be used to determine the spelling of any chord in any given key.
We'll start with the key of "C" since there are no flats or sharps in this key to get in your way. You must remember, however, that when transferring this information to other keys, all of the flats or sharps in that key signature have to be maintained.
First we assign a numerical sequence to each of the degrees of the scale. i.e. C=1,D=2,E=3,F=4,G=5.A=6,B=7.
Next are the formulas.
C minor chord = 1-b3-5. C-Eb-G.
C6 Chord= 1-3-5-6, C-E-G-A .
C7 chord=1-3-5-b7, C-E-G-Bb.
Cm7 chord=1-b3-5-b7,C-Eb-G-Bb.
C+ or Aug. chord=1-3-#5,C-E-G#,
Co or Cdim.=1-b3-b5 C-Eb-Gb.
Cdim7=1-b3-b5-bb7, C-Eb-Gb-Bbb (A)
Cmaj7=1-3-5-7,C-E-G-B.
C9=1-3-5-b7-9,C-E-G-B b-D.
Cm9=1-b3-5-b7-9,C-Eb-G-Bb-D
C11=1-3-5-b7-9-1 1,C-E-G-Bb-D-F.
C13=1-3-5-b7-9-11-13,C-E-G-Bb-D-F- A.
Apply these formulas to all keys to determine the chord equivalency.In the next section we will talk about altered chords and how to figure them out easily based on what you've already learned.
When
improvising over any chord, remember the notes that
are common to the chord. These are the
Consonances. Any notes you play outside of the chord
tones can result in Dissonances that must eventually
be resolved to the notes that exist within the chord
itself or the chord that follows. The next page deals with "Altered
Chords".
