Gain complete freedom with chords: The Chord Code

The 'spelling' of a 7th chord is : root – third – fifth – seventh

That is, when we add a seventh note to the basic triad (root – third – fifth), we get one of the seventh chords.

How many sevenths – note options

Root and fifth – there are only one note each. there are no two roots, two fifth notes.

But, the third note has two options – minor or major third

The seventh note also has two note options to choose from – minor seventh or major seventh

So when you form a seventh chord, fix the root, find the fifth, then there are two options for the third note, two options for the seventh note.
Total 4 possibilities of combination of notes.

The 4 possibilities are shown on the image at the top :

Chord             Notes
minor7           Root     5th    m3     m7
Dominant7    Root     5th    M3     m7
Major7            Root     5th    M3     M7
mM7               Root     5th    m3     M7

Dominant 7th is the chord we refer to when we say ' the seventh chord'. For example if you see G7, that is G dominant 7th.

Minor 7th is also written as '-7'. For example G-7 is G minor 7th

Major 7th can be written as Δ. For example FΔ is F major 7th.

Minor major 7th is the root chord of melodic minor, but we may not find it so often in pop music.

The four 7th chords for root C

Root is C. Fifth of C is G.

Minor 3rd is Eb. Major 3rd is E

Minor 7th is Bb. Major 7th is B.

Use the table above.

Substituting for the root, fifth, third and seventh positions with corresponding note for C root, we get :

Chord                 Notes
C minor7           C     G    Eb     Bb
C Dominant7    C     G    E       Bb
C Major7            C     G    E       B
C mM7               C     G    Eb     B

Playing the 7th chords on the guitar

Here are the 4 seventh chords of C played on the first three frets of the guitar.

C7 (C dominant 7th)

This chord you can play the lower E too, if you choose to, because it is part of the chord notes – C E G Bb.

C minor 7th

Here both the open E strings are to be omitted because E is not a chord note in C minor – Eb is. (Cminor : C Eb G, C minor7th : C Eb G Bb)

C major 7th

C minor major 7th

Here both the open E strings are to be omitted because E is not a chord note in C minor – Eb is. (Cminor : C Eb G, C minor major7th : C Eb G B)