Among the chords, the seventh chord is considered the most popular. Regardless of the type, seventh chords sound unstable, because they contain dissonances . To build one of them, you can add a third to the triad.
In jazz , seventh chords are the basis of harmonic movement.
About seventh chords
A seventh chord is a chord of 4 sounds: prima, thirds, fifths and sevenths. Its main form involves the placement of four sounds in thirds. The two extreme sounds of the seventh chord are located at intervals – the seventh, which is divided into large or small. By analogy, there are:
- Grand seventh chord – with a large seventh equal to 5.5 tones.
- Small (reduced) seventh chord – with a small seventh of 5 tones.
The purpose of seventh chords is to make the accompaniment more complex and interesting.
Types of seventh chords
Musical theory suggests the possibility of building 16 seventh chords. But not all of them are used in practice. Natural major and minor contain 4 seventh chords:
- Major – from the 3 lower sounds a major triad is obtained. Its varieties are the big major and small major chords .
- Minor is a combination of 3 minor lower sounds. It is divided into small and large minor chords .
- Augmented – formed from an augmented triad.
- Small introductory, semi-reduced, reduced introductory seventh chord – formed from a reduced triad, which was formed by three lower sounds. The difference between the small introductory and diminished is the third: in the small chord a it is located at the top and is large, and in the reduced it is small.
An augmented seventh chord is always a large chord, and a semi-reduced, or small introductory chord, is always a small one.
Harmonic minor and major contain 7 seventh chords, melodic – 5: it lacks a diminished and major major seventh chord.
Notation and fingerings
The seventh chord is denoted by the number 7. The quintsext chord is denoted by 6/5, the third quarter chord is 4/3, and the second chord is 2. The major major seventh chord is written Maj, the minor chord is m7, the semidiminished one is m7b5, the diminished one is dim/o.
This is how seventh chords are indicated on the stave.
Seventh chords built on fret steps
The step from which the seventh chord begins gives it its name:
- The dominant seventh chord is the most common among the 4-sounds. It belongs to the major types and is built on the 5th mode level.
- Small introductory: this is another name for a reduced seventh chord, which is built only in the major on the 7th step, but in general – on the 2nd step.
Here is the resolution of the sixth chord:
The seventh chord has 3 appeals:
- third quarter chord;
- second chord.
A reversal occurs when the bottom sound moves up one octave. It always contains a minor or major second. In the quintsext chord it is placed at the top, in the third quarter chord it is in the middle, and in the second chord it is at the bottom.
A seventh chord is a four-tone, formed from 3 sounds and a third. There are 16 types of seventh chords. They sound unstable due to the dissonance content . The easiest way to create a seventh chord is to add a third to 3 sounds.
Video for clarity: