The Architecture of Music

Chords

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Identifying The Notes of Chords Using Symbols: Circle, X, Triangle, Square

To identify the different notes in a chord’s interval diagram, it became necessary to symbolize the different notes in a way that could easily be understood without using symbols which are already commonly used in music today, such as numbers and letters. It quickly became apparent that geometrical objects could be used to simply describe the notes. In other words:

Circle, X, Triangle, Square = 1, 2, 3, 4.

Circle = 1 Continuous line, 1st note or Root Note
X = 2 Intersecting lines, 2nd note or Perfect 5th
Triangle = 3 Intersecting lines, 3rd note (this interval names the chord)
Square = 4 Intersecting lines, 4th note or “add” note

Identifying the notes of a chord in an interval diagram