Dominant Seventh Chords – Theory And Practice
This article is going to discuss the dominant 7th chords, usually just abbreviated to 7, e.g. E7 and A7. Don’t confuse the dominant 7th chord with the major seventh chord. The major 7th chords,or maj7, are a different chord.
Unlike the Major Chord and Minor Chord lessons where I just showed you the chord shapes and fingerings, I’m going to show you a little music theory, major scale theory, chord formula, and learn how to play dominant 7th chords.
First off, I’m going to show you what the major scale looks like. Starting off at the root note and going up to the same note one octave higher, it goes:
Where whole is a whole tone, or two frets on the guitar, and half is one fret.
If we take the E Major scale, the root note is the open sixth string. The diagram below shows the notes on the sixth string of the guitar.
Counting up the fretboard, the notes of the E Major scale are E F# G# A B C# D# and E.
The Major chord uses the first, third, and fifth notes of the Major scale. The E Major chord consists of E, G#, and B. The diagram below shows the E Major chord. Starting from the sixth string, the notes played are E, B, E, G#, B, and E.
The 7th chord formula is the first, third, fifth, and flatted seventh notes of the Major scale. E7 consists of E, G#, B, and D. The first version of E7 below uses all four fingers and can’t be used as a bar chord. The notes are E, B, E, G#, D, and E.
The next version of E7 below only uses three finger and can be used as a bar chord further up the neck of the guitar. The notes are E, B, D, G#, D, and E.
This last version of E7 is even easier and uses only two fingers. The notes are E, B, D, G#, B, and E.
You should see now that there are different ways of playing the same chord. As long as the four notes E, G#, B, and D are played, it’s an E7 chord.
We’re now going to take two variations of E7 and move it up the fretboard to play a G7 chord. Remember that we can’t use the first version because it uses all four fingers and doesn’t leave the first finger free to form the bar.
Using the same principle as before, the notes of the G Major scale are G, A, B, C, D, E, F#, G. The first, third, fifth, and flatted seventh notes forming the G7 chord are G, B, D, and F.
The diagram below shows the second version of E7 moved up to the 3rd fret to form G7. The notes are G, D, F, B, F, and G.
Finally, the diagram below shows the easy two finger version of E7 moved up to the 3rd fret to give G7. The notes are G, D, F, B, D, and G.
If either of these two chord shapes are moved up to the fifth fret, we have an A7 chord, Move it up to the seventh fret, we have a B7 chord, and so on. The root note of the chord is the note played on the sixth string.