Blues Chords On Guitar – Dominant Sevenths

B.B King, Stevie Ray Vaughan, Gary Moore, Ray Charles, Robert Johnson… All phenomenal and legendary blues guitarists that changed music history forever. Scratchy, mournful and passionate. However you want to describe blues, it remains to be one of the purest and rawest forms of music. It’s always stayed true to that original sound.

So how do you play like a Robert Johnson or a B.B King? There are many ingredients that make a blues guitarist great. It’s not like you can say: Learn this scale, and you are now a blues guitarist.

What I will do this lesson is introducing you to dominant seventh chords. Dominant seventh chords have a really specific sound that’s very popular in blues. Mastering these chords will be the first of many steps to playing blues as the grandmasters did.

Blues Chords On Guitar

Seventh Chords

We did a piece about seventh chords in this blog: Seventh Chords.

Here’s a quick summary:

Seventh chords are built from four notes. A root, a third, a fifth and a seventh:

Inside a major scale, using only the notes of a major scale, there mostly major seventh chords and minor seventh chords. Those are the seventh chords we talked about last time.

Major seventh chords have the following four notes:

  • Root
  • Major third
  • Fifth
  • Major seventh

Minor seventh chords have different types of thirds and sevenths:

  • Root
  • Minor third
  • Fifth
  • Minor seventh

As you can see, when a third is major, the seventh is major as well. When the third is minor, the seventh is minor as well. If you want to know what makes these intervals major or minor, I advise you to read the post I linked above. It’s all explained in there as clearly as possible

Now, these types on seventh chords have a really jazzy tone and can be used in blues as well, but they’re not dominant seventh chords. So what’s the difference between a regular seventh chord and a dominant seventh chord?

Dominant Seventh Chord

A dominant seventh chord is always major.

You’ll see that blues progressions often revolve around the I, IV and V chords. That’s because those are the major chords of the major scale. If you’re not familiar with the roman numerals that are used to represent chord progressions, this lesson might be helpful to you: I, ii, iii, IV, V, vi, viº.

The seventh in a major seventh chord would be major as well but in a dominant seventh chord, the seventh does not follow the third.

This means a dominant seventh chord always has the following notes:

  • Root
  • Major third
  • Fifth
  • Minor seventh

This may seem a bit abstract, so let’s see what dominant seventh chords look like:

C dominant 7:

Blues Chords On Guitar

As you can see, the seventh is not in the C major scale. This is largely what makes these chords so tense. C is the I chord of the C major scale. Let’s look at the IV chord:

F dominant 7:

Blues Chords On Guitar

Again, the seventh is a note outside of the C major scale. Finally, let’s look at the V chord:

G dominant 7:

Blues Chords On Guitar

In G7, the seventh is a note inside of the C major scale. This is important because this means the V position in a major scale is always a dominant seventh.

Blues Chords On Guitar

A dominant seventh chord has a root, a major third, a fifth and a minor seventh. This doesn’t mean those notes are only played once. It’s perfectly possible to play a root, two fifths, two thirds and a seventh. This means there are hundreds of combinations possible all over the fretboard.

I’m not going to share all those combinations, because that would simply be too difficult. The following dominant seventh chords are the most popular and the easiest blues chords. Remember that they are all major. There are no minor dominant chords.

C7

Blues Chords On Guitar

  • The low E string is muted.
  • The seventh note is played with our little finger on the third fret of the G string.

D7

Blues Chords On Guitar

  • The low E string and A string are muted.
  • The D string is played openly
  • The seventh note is played with our index finger on the first fret of the B string.

E7

Blues Chords On Guitar

  • The D, B and both E strings are played openly.
  • The seventh note is played on the open D string

F7

Blues Chords On Guitar

  • We place a barre with our index finger over all the strings.
  • The seventh note is played inside the bar on the first fret of the D string.

G7

Blues Chords On Guitar

  • The D, G and B strings are played openly.
  • The seventh note is played with our index finger on the first fret of the high E string.

A7

Blues Chords On Guitar

  • The low E string is muted.
  • The A, G, and high E string are played openly.
  • The seventh note is played on the open G string.

B7

Blues Chords On Guitar

  • The low E string is muted.
  • The B string is played openly.
  • The seventh note is played with our ring finger on the second fret of the G string

I – IV – V

As said before, blues chord progressions often revolve around the I, IV and V chords. When we play dominant seventh chords, we add the number 7 after the roman numeral.

Below you can find a chart of all I7, IV7 and V7 chords that can be found in the most popular keys.

Blues Chords On Guitar chart

So let’s play a slow blues in A. You can see on the chart we can use A7, D7, and E7. Let’s have a listen:

 

The chord progression goes like this:

I7

I7

IV7

I7

V7

I7

In our backing track this became:

A7

A7
D7

A7

E7

A7

But if we were to transpose this progression to G it would become:

G7

G7

C7

G7

D7

G7

As you can see, you can just fill in the notes from the chart above, and you can play blues in pretty much every popular key.

Outro

I hope this lesson was valuable to you. It’s a long way to play blues like the grandmasters of the genre, but dominant seventh chords are necessary for the genre, so a clear understanding is important.

If you have any questions or comments, feel free to leave them below. I will be here to answer them.

Happy strumming,

Timo

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