Tuesday, September 29, 2009

Symmetrical Root Position Triads

BoldTriads are simple chords consisting of three tones. In the most fundamental form, the Root Position, the lowest pitched tone in a triad is the root. Chords are named for the root tone. The next tone in the chord is the 3rd, which is two steps above the root. The highest pitched tone in a root position triad is the 5th, which is two steps above the 3rd.

Every major key contains a set of seven triads, one rooted in each tone of the key. Because of the sequence of whole-steps and half-steps which comprise a key, three of the triads are major, three of the triads are minor, and one triad is diminished. The structure of these three triad forms is as follows;

Major Triad
Root [ major 3rd ] 3rd [ minor 3rd ] 5th
C - - - - - - - - - - - - E - - - - - - - - - - - - G


Minor Triad
Root [ minor 3rd ] 3rd [ major 3rd ] 5th
D - - - - - - - - - - - - F - - - - - - - - - - - - A


Diminished Triad
Root [ minor 3rd ] 3rd [ minor 3rd ] 5th
B - - - - - - - - - - - - D - - - - - - - - - - - - F

The sequence of major, minor and diminished chords in each key is as follows;

I - - - - ii - - - - iii - - - - IV - - - - V - - - - vi - - - - vii - - - - I
major -- minor -- minor -- major -- major -- minor -- dimin -- major

The diagram at the top of this entry shows the triads of the keys of C, D and E on the four top strings in their symmetrical positions around the Aeolian Axis and the Void Axis.

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