#811  by ebick
 
So, now we now that building chords is more science than magic.....the science of mathematics.

....Actually, a guy named Ted Greene thinks of it more as Chemistry. In fact he wrote a book many of you might be interested in called Chord Chemistry (ISBN 0898986966). I will caution you though.....if you are like me and have short, fat fingers, you might have some difficulty, as I did, with many of his chord charts. If your hand is more the classic guitar player hand, long thin fingers, you might do allright with this.

To pick up where we left off......

A major chord is formed by combining the 1st, 3rd and 5th notes of the major scale. One of the most commonly used chords is a minor. So, how do we turn a D into a Dm? Very easily. You simply lower the 3rd note one half step. Let's put this theory to the test.

A D Major in the first position is like this:

E @ 2 = F# (3rd)
B @ 3 = D (1st)
G @ 2 = A (5th)
D @ 0 = D (1st)

So, to lower, or flat the third, we mean use an F instead of an F#. Is this not a Dm?

E @ 1 = F (Flatted 3rd)
B @ 3 = D (1st)
G @ 2 = A (5th)
D @ 0 = D (1st)

Let's try one more. A Major

E @ 0 = E (5th)
B @ 2 = C# (3rd)
G @ 2 = A (1st)
D @ 2 = E (5th)
A @ 0 = A (1st)

Am.......

E @ 0 = E (5th)
B @ 1 = C (Flatted 3rd)
G @ 2 = A (1st)
D @ 2 = E (5th)
A @ 0 = A (1st)


7th Chords

A very popular modifcation, and one that comes in 3 very common forms.

1st, the blues 7th. This is achieved by adding a note to the chord.....namely a flatted 7th (thus, the name). Let's have a look.

A D Major in the first position is like this:

E @ 2 = F# (3rd)
B @ 3 = D (1st)
G @ 2 = A (5th)
D @ 0 = D (1st)

And D7 in the first position......:

E @ 2 = F# (3rd)
B @ 1 = C (flatted 7th)
G @ 2 = A (5th)
D @ 0 = D (1st)

And another

G Major Barred

E @ 3 = G (1st)
B @ 3 = D (5th)
G @ 4 = B (3rd)
D @ 5 = G (1st)
A @ 5 = D (5th)
E @ 3 = G (1st)

We can do this one a couple of ways

E @ 3 = G (1st)
B @ 3 = D (5th) or B @ 6 = F (Flatted 7th)
G @ 4 = B (3rd)
D @ 3 = F (Flatted 7th)
A @ 5 = D (5th)
E @ 3 = G (1st)

Hopefully, this triggered something in your mind.......when you see chords with numbers, such as A6, D9, E4....those number mean "add that note".

We also have Maj7 and Min7

For a Maj 7th, we simply add the natural 7th from the major scale. Here's an example. The A scale is made up of the following notes:

A-B-C#-D-E-F#-G#-A, and the chord, A-C#-E. An Amaj7 adds the G#.

E @ 0 = E (5th)
B @ 2 = C# (3rd)
G @ 1 = G# (7th)
D @ 2 = E (5th)
A @ 0 = A (1st)

Here's a nice Gmaj7

E x (muted)
B @ 3 = D (5th) 2nd finger
G @ 4 = B (3rd) 4th finger
D @ 4 = F# (7th) 3rd finger
A x (muted)
G @ 3 = G (1st) 1st finger

And, finally, the Minor 7th

To achieve this, we must do two things. First, lower the third to get the minor, and second, add the flatted 7th

Here's an Em7

E @ 0 = E (1st)
B @ 3 = D (Flatted 7th)
G @ 0 = G (Flatted 3rd)
D @ 2 = E (1st)
A @ 2 = B (5th)
E @ 0 = E (1st)

or this one, a C#min7

E @ 4 = G# (5th)
B @ 5 = E (Flatted 3rd)
G @ 4 = B (Flatted 7th)
D @ 6 = G# (5th)
A @ 4 = C# (1st)


At this point, I'm going to move on to the next subject, though I

A) encourage folks within the community to add other chord formulations to this topic, and
B) reserve the right to come back here and do more of this myself

 #821  by Budz
 
Could you please explain Harmonic minor, if you get a chance.