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| So far we have used only odd numbers to describe chords. | |
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| For over 500 years music theory has described harmony in terms of chords based on the interval of a third, 1 - 3 - 5 - 7 - etc. This is called tertian harmony. A theory that chords are built on fourths is called quartal harmony. If a composer is thinking "quartal" then the cadences will have these chords. Occasional quartal chords can be analyzed in tertian harmony. |
Chords built on thirds:
Chords built on fourths: |
| For this and other reasons, even numbers are sometimes used. | |
| C H O R D S |
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