General Guitar Playing Music Theory

Published on June 23rd, 2014 | by Sam

2

Music Theory – 7th Chords

Most of jazz uses 4 note chords that are commonly called “7th chords.”  In order to spell these we are simply going to add a 4th note to the triads we’ve already figured out how to spell.  Let’s start again with the Major family – the Major 7th chord.

Major 7th Chord

We are just going to add the 7th note of the scale to the major triad to get the major 7th chord. Simple right?  Our triad spelling was R35.  So that makes our Major 7th chord spelling:

R357

Let’s use the key of D again:
D E F# G A B C#

Dmaj7 would be:
D  F#  A  C#
R   3   5   7

That’s it!

Dominant 7 Chord

The next chord we’ll create is the dominant 7th chord.  This chord is very common both in jazz and pop.  The spelling is the same as the major 7th but with a lowered 7th.  So it will be:

R 3 5 b7

So D7 is:

D  F#  A  C
R   3   5  b7

Minor 7 Chord

The minor 7 chord is simply a Dominant 7 chord with a lowered 3rd.  The spelling is:

R b3 5 b7

Dmin7 is:

D  F  A  C
R b3 5  b7

Minor 7b5 (Half Diminished)

The half diminished chord is a less common chord, but still comes up a lot in jazz.  It’s simply a minor 7 chord with a lowered 5th.  The name ‘half diminished’ comes from the triad – diminished – but the 7th is a lowered 7th (as opposed to a diminished 7th interval).  They commonly come up in the ii-V-i in a minor key as the ii chord.

The spelling is:

R b3 b5 b7

The Dmin7b5 chord is:

D  F  Ab  C
R b3  b5  b7

Diminished 7 Chord (Fully Diminished 7th)

The Diminished chord is another somewhat rare chord.  In jazz it’s most often heard as part of a Dominant 7b9 chord.  It’s rarely heard in pop or country music.  They come up now and then in blues.  The spelling of this chord can be a bit confusing though.
R b3 b5 bb7

So they are the same as a half diminished chord but with a double flatted 7th.  So the 7th degree has to be lowered 2 half steps.  The part of this that gets tricky is that they are still the same LETTER as the original 7th.  So in D our 7 was C#.  If we lower that 2 half steps we end up with Cb, which is the same as B.  The technical name still has to be Cb because the 7th has to some type of C.

Do7 is:
D  F  Ab  Cb
R b3  b5  bb7

Minor Major 7

Minor and Major, huh?!  Ok, this one is really a combination of the Minor triad with the major 7th.  It’s really only heard as a ‘tonic minor’ – or as the i chord in a minor key.  These hardly come up in pop or country music, though they are somewhat common in jazz.  The spelling is simple, but the chord is a little strange.

R b3 5 7

DminMaj7 is:

D  F  A  C#
R b3  5  7

Diatonic 7th Chords

That’s how you spell all the 7th chords on their own.  These also have a pattern for how they occur in the keys.  When we came up with the diatonic triads, we just used every other note.  If we add another pitch to that we end up with (in Eb):

D Eb F G Ab Bb C
Bb C D Eb F G Ab
G Ab Bb C D Eb F
Eb F G Ab Bb C D
1 2 3 4 5 6 7

Again, analyzing these all compared to the numbers above, we would end up with this pattern:
Maj7   Min7  Min7  Maj7  Dom7  Min7  Half Diminished

In the key of Eb then,

Ebmaj7  Fmin7  Gmin7  Abmaj7  Bb7  Cmin7  Dmin7b5

This pattern holds up in every key, so again we can easily figure out all of the diatonic 7th chords very quickly.

That does it for my music theory basics series!  Make sure to check out the others in the series too:

Part 1-Major Scales | Part 2-Key Signatures and Cycle of Fourths | Part 3-Triads

(Photo Credit: Surat Lozowick)

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2 Responses to Music Theory – 7th Chords

  1. ryan says:

    I understand everything up until the diatonic seventh chords. You have listed the scales wrong
    the d scale is D-E-F#-G-A-B-C#. But then I just thought you flattened the notes according to the pattern major-no change and minor- flat. until I came across the dom7 which you flatted the A to Ab but in the G scale which is G-A-B-C-D-E-F# you did not flat the D(dom7) to a Db. Either you skipped mentioning something or you messed up somewhere. Please help

    • Sam says:

      Ryan- I just want to make sure I’m understanding your questions:
      These spellings are how to spell each individual chord based on the scale. So a D dominant chord is being based off the D scale. In other words, I’m not spelling the dominant chord IN D, but the D Dominant chord (which would be in the key of G – just a different way of thinking about it).

      The Ab occurs in the Half Diminished (and fully diminshed) chords.

      Let me know if that helps clear things up. If not, don’t hesitate to email me at sam@samsmileymusic.com and we can go from there. Thanks!

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