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Four-note chords (seventh chords)

A four-note chord is based on a three-note chord to which is added an additional note located at an interval of seventh of the root note.

Before diving into 4-note chords, be sure to be familiar with the three-note chords.


Like three-note chords, four-note chords are formed, in the root position, by a stack of thirds.

FIGURE 1 - In root position, a four-note chord is constituted by a stack of thirds
Third Third Third

A four-note chord can therefore be broken down into a three-note chord, to which is added an additional note, called seventh because it is written at an interval of 7th of the root note of the chord.

FIGURE 2 - A four-note chord is formed of a three-note chord (below, a major perfect chord) and an extra note located at a seventh interval of the root
7th Perfect major chord


Audio of figure 2 (the notes are first arpeggiated then played all at once)

The third and fourth notes of the chord together form a third. Since this third may be either major or minor, it is possible, from each three-note chord, to produce two four-note chord variants.

In the following paragraphs, we will study the four-note chords from the three-note chords studied in the course on three-note chords.

For each chord, we try to best describe the sound effect produced by the chord to better help you recognize them by ear.

Four-note chords based on the perfect major chord

Dominant seventh chord

The dominant seventh chord is formed of a major perfect chord with a minor third on top of it. The interval formed by the root note and the upper note is thus a minor seventh.

Be careful not to confuse the nature of the seventh (here, minor) and the nature of underlying three-note chord (here, major).

FIGURE 3 - Dominant seventh chord in root position
G Major perfect chord Maj. 3rd Min. 3rd Dominant seventh chord Min. 3rd Min. 7th


Audio of figure 3 (the notes are first arpeggiated then played all at once)

The dominant seventh chord is so called because it is "naturally" present on the dominant (the 5th degree) of any major key.

For example, in C major, the dominant is G (because it is the 5th note of the scale). If you stack three thirds from this note, you naturally get the seventh dominant chord.

This four-note chord is the most frequently encountered, in all styles of music. It is particularly at the base of the Blues. However, it does not have the same function in all music. The name "dominant seventh" is relevant in classical, but much less (if at all) in jazz for example. That's why, in jazz or rock, we use the term seventh chord.

By ear, this chord is quite consonant and sweet. The presence of a major third, a perfect fifth and a minor seventh (less tense than a major seventh) makes it the most consonant seventh chord, hence its massive use in all musical styles.

Last update on 2021/05/07

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