Now we will go on to constructing chords consisting of four notes. These are called “seventh chords” because there is an interval of a seventh between the lowest and highest notes. Seventh chords are a basic staple in popular music. As you recall, chords are built up in thirds, and there are two kinds of thirds, major and minor. The major third consists of four half steps and the minor third consists of three. Remember that the half step is the smallest interval on the piano.
The seventh chord is used most frequently in rock music, sometimes called the dominant seventh chord. These notes are the I (first), 3 (third), 5 (fifth) and b7 (flattened seventh) notes of the major scale.
The chord formula for the seventh chord is:
1 3 5 b7
A flattened seventh, (b7), is created by lowering the seventh note of the scale by one semitone. The seventh chord is simply a major chord with a flattened seventh note added.
When the numeral “7” stands alone after a chord root, that means a “dominant seventh” chord is what is being talked about here.
The G7 chord is made from the G major scale. It is good to know your scales because chords come from scales. And chord progressions come from chords and progressions make songs. That's the formula for success in music theory and now you have a good foundation to build on.
Using the above chord formula on the G major scale below, it can be seen that the G7 chord contains the notes G, B, D, and F. When the seventh note of the G major scale (F#) is flattened, it becomes an F note.
G A B C D E F# G = Note Name
1 2 3 4 5 6 7 8 = Note Number
1 3 5 b7 = Seventh chord Formula
G B D F = G Major chord
Remembering our past lesson on inversions, because the G7 chord contains four notes, there are three inversions plus the root inversion. So, the first inversion is 3 5 b7 1 or C-B-D-F-G, the second inversion is 5, b7, 1, 3 or C-D-F-G-B. The third inversion is b7, 1, 3, 5 of the G7 chord or C-F-G-B-D.
So, to summarize what we’ve learned about the Seventh Chord:
The seventh chord is formed by adding a flattened 7th note to the major chord.
Thus, the C7 chord consists of the first, third, fifth and flattened seventh notes of the C major scale. So we have a major triad (major third and minor third) and above that a minor third.
C D E F G A B C = C Major Scale
1 3 5 b7 = Chord Formula
C E G bB = Notes
The symbol “maj7” stands for a “major seventh” chord consisting of a major triad (major third and minor third). And on top of that, a major third.
The Fmaj7 chord contains the notes F, A, C, and E.
In the key of C major, here are the basic 7th chords:
Cmaj7
Dm7
Em7
Fmaj7
G7
Am7
Bm7b5
I = maj7
ii = m7
iii = m7
IV = maj7
V = 7
vi = m7
vii = m7b5
So whenever you want to play a vi-ii-V-I progression, you can embellish all of those chords, or none if you don't want to, with that seventh note.
Learn to use these chords because they are the building blocks for improvisation in blues and jazz. They provide the basis of the tension and the chords sound more lush.
So, we’ve completed some basic training on 7th chords. But did you know that there are eight types of 7th chords in all keys? Here we go:
The Major 7th
The Major 7th with a raised 5th (+5)
The dominant 7th
The dominant 7th with a flatted 5th (-5)
The minor 7th
The minor.major 7th
The half-diminished 7th
The diminished 7th
Wow, so a seventh chord can be major, minor, augmented or diminished. Remember that the 3rd is the note that determines whether it is major or minor.
The 7th chord formula is: 1 - 3 - 5 - b7
The major 7th chord formula is: 1 - 3 - 5 - 7
The minor 7th chord formula is: 1 - b3 - 5 - b7
You now have quite a vocabulary of piano chords under your belt. Your options increase as a cool keyboard player to play more fuller sounding chords. I love the sound of seventh chords. It's a fun chord. Use them in your playing of jazz and country songs and enjoy.
I have been playing music with many talented musicians for a very long time. I love all genres of music, especially jazz and blues. I teach piano to all ages and at all levels.
