2.15 The dominant seventh chord
|Category: Harmony | Tags: Chords, Seventh chords|
In Chapter 2.9 Chords you’ve learned that a four note chord is called a seventh chord and is comprised of 3 thirds. In this chapter, you will learn about the seventh chord built on the fifth tone of the scale. This chord is called dominant seventh chord. In the videos and examples I show how to make this chord.
1. The most important seventh chord
Because seventh chords are a lot more complex than triads, you learn about seventh chords starting at level 5. However, there is one seventh chord that is so common that it is important to pay attention to it now. Even in the simplest music you will encounter this chord. For example, if you play an F and G on the piano with the left hand and a D with the right hand, you are actually playing a seventh chord called dominant seventh.
2. What is a seventh chord?
The seventh chord G - B - D - F is made up of four notes. The lowest note G is called the root, the B is called the third, and the D is called the fifth. What is the name of the highest note, the F?
The highest note F is called seventh. This, because the distance between the lowest note G and the highest note F is a seventh.
3. What is a dominant seventh chord?
A triad built on the fifth tone (dominant tone) of a scale, the fifth degree (V), is called dominant. In C major, G is the fifth tone. The triad made on the G, the fifth degree (V), is comprised of the notes G - B - D. In C major, the triad G - B - D is called dominant, this is the dominant chord.
Next we are going to add a seventh to this dominant chord, or in other words we are going to make it a seventh chord. In the example at point 2 you have seen that F is the seventh. We get the seventh chord G - B - D - F. As this seventh chord is made on the fifth note of the scale, this chord is called dominant seventh chord. Dominant, because it is made on the fifth note of the scale.
The dominant seventh chord in C major.
4. How does the dominant seventh chord resolve?
The fifth degree has an unstable character and is often followed by the first degree. This is because the fifth degree contains two important tones from the scale, the dominant tone and the leading tone, that want to resolve to the tonic.
In C major, G - B - D is the dominant chord. The root of this chord is G. The G is the fifth tone of the scale of C major, the dominant tone, and wants to resolve to the tonic, the C. The third of the dominant chord is B. The B is the seventh tone of the scale of C major, the leading tone, and also wants to resolve to the tonic, the C.
Making the dominant chord a dominant seventh chord adds an unstable tone. This is because the seventh, F, is a half step above the third, E of the first degree and wants to resolve to it.
In C major, G - B - D - F is the dominant seventh chord. The seventh F of this chord is the fourth tone of the scale of C major and is a half step above the third tone of the scale, the E. The first degree is comprised of the tones C - E - G. The dominant seventh chord has three tones that resolve to tones of the first degree. Namely, G and B resolve to C and the F resolves to E.
Because of the seventh, the dominant seventh chord is even more powerful than the dominant chord. The chord progression dominant - dominant seventh - tonic is often used.
Listen to dominant - dominant seventh - tonic
5. The dominant seventh chord simplified
In practice, you will not encounter the dominant seventh chord G - B - D - F in this form very often. For example, this chord is not easy to play on the piano and the notes are all close together, so it does not sound clear. This is why the dominant seventh chord is usually simplified. You can do this in a number of ways. You can omit a note, you can play an inversion, or you can omit a note and play an inversion. You can also divide the notes between two hands (for the piano) or divide them between multiple instruments.
Omit a note
To simplify the dominant seventh chord, it is possible to omit notes without changing the chord. The tones you certainly can't omit are the root G and the seventh F. If you omit the root, the chord becomes B - D - F. The B is now the new root and you have a completely different chord, namely the seventh degree. If you leave out the seventh note F, then the chord becomes G - B - D and you have an ordinary dominant chord again.
The notes that can be omitted are the third B and the fifth D. As the third B is an important note, the leading tone of the scale, the fifth D is the first to be considered for omission. The dominant seventh chord can be played well without the D and is the one you will encounter or use the most. The dominant seventh chord without the leading tone B also occurs.
Play an inversion
In Chapter 2.11 Root position and inversion you’ve learned how to make inversions of triads. If a triad is inverted, the root is not the lowest note. The lowest note is the third or the fifth. You can also make inversions of the dominant seventh chord. The lowest note is the third, the fifth or the seventh.
Omitting a note and inverting
The dominant seventh chord most often occurs in an inversion with a note omitted. For example, G - B - D - F is played as B - D - F - G. This is an inversion, G is played an octave higher. Then the D is omitted. You get B - F - G. This form of the dominant seventh chord is most commonly used for the piano.
But you can also omit the B in the inversion B - D - F - G. You get D - F - G. You also often see this form of the dominant seventh chord.
Divide between two hands or multiple instruments
On the piano, the notes of chords are often divided between two hands. For example, if you play an F and a G with your left hand and a D or a B with your right hand, you are playing a dominant seventh chord. Are you playing with other instruments together? Then it is also important how the notes of a chord are distributed among the different instruments. For example, if the double bass plays a G, the cello a B, the viola a D and the violin an F, then together they play the dominant seventh chord G - B - D - F.
Inversion of the dominant seventh chord in C major.
6. The notation of the dominant seventh chord
The dominant seventh chord is indicated by: V7.
7. Ear training: learn to recognize chord functions by ear
It is also possible to distinguish the differences between the degrees I, IV, V and V7 by ear. Listen to four examples:
Listen to I-V-I, or tonic - dominant - tonic
Listen to I-V7-I, or tonic - dominant seventh - tonic
Listen to IV-V-I, or subdominant - dominant - tonic
Listen to IV-V7-I, or subdominant - dominant seventh - tonic
To learn to recognize the different degrees and chord functions by ear, a number of different exercises have been made for the enthusiast. These exercises are called Recognizing degrees, Notating degrees and Degrees and melody and can be found from level 2 to level 6.
Find out more about Recognizing degrees, Notating degrees and Degrees and melody in Chapter 2.25 Degrees: ear training.