The dominant 7th chord is built from the 5th note of the major scale. It is used in all types of music but they are the main chords in Blues music.
This chord also acts as a lead in for a chord change usually a 4th away like from a G7 to a C chord.
Below is an example of the C scale. The G is the 5th note in this scale.
If we take every other note after the G we will build a G7th chord.
G – B – D – F These are the notes that make up a G7th chord.
Every major scale has a dominant chord built on it’s 5th note.
G Mixolydian Mode
The G mixolydian mode is the C major scale starting from the 5th note G. This scale along with others is used for improvising over dominant chords.
You will see this chord as the main chord in blues progressions. It will be used for all three chords in a 12 bar blues like C7, F7 and G7. You could also use dominant 9th chords
Years ago bands would use the Mixolydian scale as the main source for improvising over this progression. It is actually in 3 different keys because there is only one dominant chord in a najor scale.
Now the blues scales are the main scales used. In a Jazz-Blues sound many other scale and modes are used because they use a lot of chord substitution with altered chords.
Dominant Chord Forms
Here are some common chord forms for this chord.
These chords are movable just move to the root note. On the first chord just play the 1st 4 strings.
Here is where the roots are for the above chords going from left to right.
1st Chord – Root – 6th and 3rd String
2nd Chord – Root – 6th and 1st Strings
3rd Chord – Root – 4th String
4th Chord – Root – 5th and 2nd Strings
5th Chord – Root – 5th String
Dominant chords can have other notes in them along with the 7th. Any chord that is built from the 5th note of the Major scale is a dominant chord including altered chords. They usually all have a flatted 7th.
If a chord name has a 7 after the note name it’s a dominant chord. If it has a maj7 after it’s not a dominant chord.
Dominant chords can be 9th, 11th and 13th chords too. Altered chords with a flatted 7th can also be considered dominant chords too.
Dominant 7th – She’s a Woman
A good example of this chord is the Beatles song “She’s a Woman”. John uses the dominant 7th chord forms shown below.
She’s a Woman – Cd’s – Vinyl
She’s a Woman – Tab
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Dominant Chords in Major Scales
Here is a list the keys and dominant chord for that key. The dominant 7th is always built from the 5th note of a Major scale. This is also true in the Harmonic and Melodic minor scales.
The F♯ and G♭ are the same pitch just spelled different for each key.
Dominant 7th Chords
Here are dominant 7th chords for all the major keys.
These chords are used a lot in all styles of music especially Blues music.
Most of these chords are movable just keep track of where the root notes are.
I hope you found this page useful.