Guide to Chord Formation by Howard Wright (Howard@jmdl.com)
Chapter 4 : 7th Chords
4.0 : 7th Chords
4.1 : Minor 7ths
For
minor chords there is one common type of
7th - the
minor 7th. As you might expect, you start with the minor triad, then add
the minor 7
th.
So, as an example lets take
D minor 7th (
Dm7).
-
The spelling is: 1st, minor 3rd, 5th, minor 7th.
Using the table of intervals above, we count up from D to get the other notes.
To get the min 3rd, count up 3 semitones - F
To get the 5th count up 7 semitones - A
To get the min 7th count up 10 semitones - C
So Dm7 is made up of the notes: D F A C
If you use the open D string for the D note, you could
use these two shapes:
EADGBE EADGBE
xx0211 xx0565
Dm7 Dm7
Min/maj 7th chords
There is another chord called the
min/maj7th. This is a bit
of a
weird fish, but you might come across it once in a
while. It's made up by taking the
minor triad and adding
the
major 7th to it.
-
So Dm/maj7th would be: D F A C#
4.2 : Major 7ths and flat 7ths (dominant 7ths)
With major triads you can build two types of 7
th chord.
If you add the
major 7th of the scale, you get the major 7
th
chord. If you add the
flat 7th to the major triad you get
the so-called
dominant 7th chord.
When
guitarists talk about '7
th chords' as in
12-bar blues etc,
then they mean chords with the
flat 7
th.
Major 7
th chords are written as
Cmaj7,
Dmaj7 etc., but the flat 7
or 'blues' 7
th is written simply as
C7,
D7 etc.
So for a major 7
th chord the spelling is:
-
1st major 3rd 5th major 7th
If we start with F as our root and count up, we get this:
Go up 4 semitones from F for major 3rd: A
Go up 7 semitones from F for 5th: C
Go up 11 semitones from F for maj 7th: E
So the notes of the chord Fmaj7 are: F A C E
To build an
F7 chord, the only difference is that we add a
flat 7 instead of a maj7. So we add an
Eb instead of
E,
so the notes of a
F7 chord are:
F A C Eb
As with simple
triads, you can double up on some of the notes
to make a chord. With 7
th chords you could double up on
the
root,
3rd,
7th or
5th.
-
Take a standard 7th chord, E7:
EADGBE
020100
The notes are: E B D G# B E, so the root and 5th have both been doubled.
Guide to Chord Formation by Howard Wright
Reformatted and noded (with permission) by Space Butler
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