Chords - Seventh Chords ②

1. Various Forms of Seventh Chords

In the previous section on seventh chords ①, we studied the four basic types of seventh chords: major 7th, minor 7th, dominant 7th, and diminished 7th. As seen in the earlier key section, these seventh chords are the diatonic chords of the major scale and frequently appear in music.

In this section, you will learn about various forms of seventh chords that are often used to enrich harmonies in genres like pop, film music, and jazz, as well as sixth chords that can substitute seventh chords.

2. Diminished Seventh Chord (Dim7)

The diminished seventh chord is built by adding a diminished seventh interval to a diminished triad, consisting of the root, minor third, diminished fifth, and diminished seventh. For example, the C diminished seventh chord is composed of C (root), E♭ (minor third), G♭ (diminished fifth), and B♭♭ (diminished seventh).

The C diminished seventh chord is commonly called 'C diminished seven' and is notated as Cdim7 or C°7 in sheet music.

The diminished seventh chord has a very unique and symmetrical structure, where all intervals between notes are minor thirds. This means the notes are closely spaced, causing the tones to clash and produce strong tension when sounded together. Due to this structural characteristic, the diminished seventh chord has a very unstable sonic nature.

3. Major Seventh Sharp Five Chord (Maj7#5)

The major seventh sharp five chord is a major seventh chord with the fifth raised by a half step, consisting of the root, major third, augmented fifth, and major seventh. For example, the C major seventh sharp five chord is composed of C (root), E (major third), G# (augmented fifth), and B (major seventh).

This chord is commonly called 'C major seven sharp five' and is notated as CM7#5, Cmaj7#5, or C△7#5 in sheet music.

The major seventh sharp five chord adds tension with the augmented fifth to the bright and dreamy feel of the major seventh chord, creating a mysterious yet tense sound.

4. Minor Major Seventh Chord (MinMaj7)

The minor major seventh chord is built by adding a major seventh interval to a minor triad, consisting of the root, minor third, perfect fifth, and major seventh. For example, the C minor major seventh chord is composed of C (root), E♭ (minor third), G (perfect fifth), and B (major seventh).

This chord is commonly called 'C minor major seven' and is notated as CmM7, CmΔ7, or C-△7 in sheet music.

The minor major seventh chord combines the dark atmosphere of the minor triad with the tension of the major seventh, producing a mysterious and somber sound.

5. Suspended Seventh Chord (7sus)

The suspended seventh chord is formed by replacing the major third of a dominant seventh chord with a perfect fourth, consisting of the root, perfect fourth, perfect fifth, and minor seventh. For example, the C suspended seventh chord is composed of C (root), F (perfect fourth), G (perfect fifth), and B♭ (minor seventh).

This chord is commonly called 'C seven sus' and is notated as C7sus or C7sus4 in sheet music.

The suspended seventh chord has less tension and a softer feel than the dominant seventh chord. Therefore, it is frequently used in popular music to replace the dominant seventh chord for a smoother sound.

6. Sixth Chord (6th Chord)

The sixth chord is built by adding a major sixth interval to a major or minor triad. There are two types: the major sixth chord, which adds a major sixth to a major triad, and the minor sixth chord, which adds a major sixth to a minor triad.

In chords, the sixth interval creates less tension than the seventh and produces a softer sound. Because of this characteristic, in various modern music genres, musicians often use major sixth chords instead of major sevenths, or minor sixth chords instead of minor sevenths or minor major seventh chords, depending on the mood they want to express. In jazz and other rich, dynamic musical styles, it is also common to add a sixth as a tension to a seventh chord, creating a chord where the sixth and seventh tones sound simultaneously.