Triads (or chords) are an important part of music. They are built by combining 3 (therefore TRI-ad) notes that are separated by an interval of a third. Remember that a minor third is 3 half steps and a major third is 4 half steps (or two whole steps). The interval always uses three note names. Example: C,d, E, three note names = a third.

The quality of the chord is based on the type and order of the intervals.

The chart below should be read from the lowest pitch (on the bottom) to the highest pitch. Major is abbreviated as "M" and minor as "m". Diminished triads are abbreviated with a "º" while augmented is abbreviated with a "+" symbol.

Major	minor	diminished	Augmented
m3	M3	m3	M3
M3	m3	m3	M3

Triads have a "natural quality". This is the native character of the triad before any notes are altered either by a key or accidentals. The table below lists the seven possible spellings and their native quality. To change a chord's character, simply re-order the thirds by use of accidentals.

Example: ACE occurs naturally as a minor triad. To make it major, we raise the third one half step so it becomes AC#E. Please note that the perfect fifth (the outer interval) is unchanged. Major and minor triads differ only in internal quality; both chords have the same outer interval (a perfect fifth).

The diminished triad only occurs naturally once (BDF). It's outer interval is a diminished fifth.

The augmented triad does not occur naturally. It is always a result of having one or more note(s) manipulated. It's outer interval is an augmented fifth.

Learn the triad spellings. They will be an enormous help to you. When you know the spellings and their native quality, you can find almost any interval within them.

Other chords are built by adding thirds to the triad. Most common among these are the seventh chords. Sevenths get their name because adding the third to the triad creates an outer interval of a seventh.

Adding still more thirds creates ninths, elevenths, and thirteenths.

Chords may be played in root position with the note upon which it is built as the bottom note of the chord or in inversions with other chord tones on the bottom.  If the third of the chord is in the bass, it is 1st inversion. With the fifth on the bottom, the chord is in 2nd inversion. Sevenths can also have a third inversion and ninths a fourth.

For more detailed study of music theory visit www.teoria.com

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Last modified: 07/23/06.