How are guitar
chords built? What makes a chord minor or major? If
you're not sure about this, then read on ... Some background
theory makes a tremendous help when learning how to play guitar chords.
Let's get
started with the C major scale :
| C
Major Scale |
C D E F G A B |
| |
1 2 3 4 5 6 7
|
Triads (chords that are built with 3 notes) and seventh chords
(chords that are built with 4 notes) are based on thirds.
There are 2 kinds of thirds (or 3rds) :
| minor third |
interval of 3 half notes |
symbol : b3 |
| major third |
interval of 4 half notes |
symbol : 3 |
Let's start by stacking 2 thirds on the 1 (first note) of the C major scale
The result is a
C major triad or C. From C to E is a major third and from E to G a minor
third: every major chord has this structure. The thing to remember here is what we
call the chord formula for major chords: 1-3-5
Another thing to remember : another name for the 1 of a chord is the root.
Let's do the same for the 2 of the C major scale :
The result is a D minor triad or Dm. From D to F is a minor third and
from F to A is a
major third : every minor chord has this structure.
Again the thing to remember is the chord formula for minor chords : 1-b3-5
Now we're going to skip a few notes and stack thirds on the 7 of the C major scale:
The result now is a B diminished triad or Bdim. From B to D is a minor
third and
from D to F is also a minor third : every diminished triad chord has this structure.
So the chord formula of diminished chords is : 1-b3-b5
I'll summarize and complete the other notes of the C major scale :
| |
Notes |
Formula |
Chord Name |
Symbol |
| 1 |
C E G |
1 3 5 |
C major |
C |
| 2 |
D F A |
1
b3 5 |
D minor |
Dm or D- or Dmin |
| 3 |
E G B |
1
b3 5 |
E minor |
Em or E- or Emin |
| 4 |
F A C |
1 3 5 |
F major |
F |
| 5 |
G B D |
1 3 5 |
G major |
G |
| 6 |
A C E |
1
b3 5 |
A minor |
Am or A- or Amin |
| 7 |
B D F |
1
b3 b5 |
B diminished |
Bdim or B° |
Augmented
triads are probably the least common in rock and pop, but they definitely do
happen occasionally, and they are used fairly regularly in jazz and classical music.
An
augmented triad is built with a root (I) and a 3rd (III), just like a major triad.
However, the 5th is sharped in this case (#V). Therefore an augmented triad is
comprised of I - III - #V. In the key of C, this would give us C - E - G#.
C
augmented triad = C - E - G#
___________________________________________________________________________
The construction
of seventh chords follows the same principle as constructing triads :
stacking 3rds on top of each other. Triads were made by stacking 2 thirds on top of
the root. Seventh chords are constructed by stacking 3 thirds on top of the root.
Let's stack 3 thirds on the 1 of the C major scale :
The result is a C major 7 chord or Cmaj7. From C to E is a major third,
from E to G is a
minor third and from G to B is a major third : every major 7 chord has this structure.
So the chord formula for major 7 chords is : 1-3-5-7
Let's do the same for the 2nd note of the C major scale :
The result is a D minor 7 chord or Dmin7. From D to F is a minor third,
from F to A is a major third and from A to C is a minor third : every minor 7 chord has
this structure. So the chord formula for minor 7 chords is : 1-b3-5-b7
Now let's skip some notes and stack 3 thirds on top of the 5th note of the C major scale :
The result is a G dominant 7 chord or G7. From G to B is a major third,
from B to D is a minor third and from D to F is a minor third : every dominant 7 chord has
this structure. The chord formula for dominant 7 chords is : 1-3-5-b7
We'll skip some more notes and stack 3 thirds on top of the 7th note of the C major scale
:
The result is a B half diminished chord or Bm7b5. From B to D is
a minor third, from D to F is a minor third and from F to A is a major third : every half
diminished 7 chord has this structure.
The chord formula for half diminished 7 chords is : 1-b3-b5-b7
I'll summarize and complete the other notes of the C major scale :
| |
Notes |
Formula |
Chord
Name |
Symbol |
| 1 |
C E G B |
1 3 5
7 |
C
major 7 |
Cmaj7 |
| 2 |
D F A C |
1
b3 5 b7 |
D
minor 7 |
Dm7
or D-7 or Dmin7 |
| 3 |
E G B D |
1
b3 5 b7 |
E
minor 7 |
Em7
or E-7 or Emin7 |
| 4 |
F A C E |
1 3 5
7 |
F
major 7 |
Fmaj7 |
| 5 |
G B D F |
1 3 5
b7 |
G
dominant |
G7 |
| 6 |
A C E G |
1
b3 5 b7 |
A
minor 7 |
Am7
or A-7 or Amin7 |
| 7 |
B D F A |
1
b3 b5 b7 |
B
half diminished |
Bm7b5
or Bmin7b5 |
Diminished Seventh chords
A
diminished seventh chord begins with a diminished triad and you add a
"double-flat" seventh, which is really the same thing as the sixth (this is
another one of those things in music that you just have to accept as
truth without really questioning why). The diminished seventh chord has an
interesting structure and can perform very versatile functions within a chord progression.
Cdim7
= C - Eb - Gb - Bbb (A) (I - bIII - bV - bbVII)
The
interesting thing about the diminished seventh chord is that it is a "symmetrical
chord." Notice that each interval in the chord is a minor third, or three half steps.
Because of this, you could say that any of the notes of the chord could be considered the
root note--or, to put it another way, a Cdim7 is the same as an Ebdim7, which is the same
as a Gbdim7, which is the same as an Adim7. Strange, huh? Check it out:
Cdim7
= C Eb Gb A
Adim7 = A C Eb Gb
Ebdim7 = Eb Gb A C
Gbdim7 = Gb A C Eb
Augmented Dominant Seventh chords
An
augmented seventh chord is just like a regular dominant seventh chord, except that the
fifth is raised (a.k.a. sharped, a.k.a. augmented):
C7aug
= C - E - G# - Bb
Augmented Major Seventh chords
An
augmented major seventh chord is just like a regular major seventh chord, except that the
fifth is raised (a.k.a. sharped, a.k.a. augmented):
Cmaj7+5
= C - E - G# - B
Minor/Major Seventh chords
A
minor/major seventh chord begins with a minor triad, but unlike the minor seventh chord,
it adds a natural seventh degree to the chord:
Cm(maj7)
= C - Eb - G - B
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tom@newjerseyguitarlessons.com
