TRIADS AND OTHER CHORDS




In western tonal music we tend to use normally four types of  three-note chords, plus a couple of four-note chords.  There are more also, but these are the most widely used.

Three-note Chords

Three-note chords (called triads) have a characteristic sound to each type, based on the interval spacing between the three notes in the chord.  The spacings are as follows:  (see Music Theory / Intervals for a  discussion of intervals)

Chord
type
lower
interval
upper
interval
Major
M2
m2
Minor
m2
M2
Diminished
m2
m2
Augmented
M2
M2


So, a major chord with a bottom (root) note of C would contain: these notes: C, E, G

A minor chord built on a bottom (root) note of A would contain these notes: A, C, E.

A diminished chord built on a bottom (root) note of B would contain these notes: B, D, F

an augmented chord built on a bottom (root) note of C would contain these notes: C, E, G#

The note names need to be two letters apart.  In the last example, you say C, E, G#, not C, E, A-flat.

These chords don't have to appear with the root note always on the bottom.  When they do, that's called 'root position'.  But when the middle note in the definition appears on the bottomm, that's called 'first inversion.'  And whtn the top note in the definition appears on the bottom, that's called 'second inversion.'

Four note chords

The most popular four note chord is called a seventh chord.  Normally it's made of a major chord plus a note that is a minor seventh, or sometimes a major seventh, above the root.  For example,

G, B, D, F

is a G major chord with a minor 7th above it, called Gm7, where the capital G stands for major, and the m7 is the minor 7th above.

There are also 9th chords, with a major or minor 9th above the root note.  Jazz guitar players keep mentioning flatted 13th chords..... which would be an octave plus a sixth above the root.

These are the basic types of chords available.  But the next step is to understand how people commonly use them in a piece of music.

CHORD FORMS                                    Music Theory