Guide to Chord Formation by Howard Wright (
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 7th.

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:
  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 7th chord. If you add the major 7th of the scale, you get the major 7th chord. If you add the flat 7th to the major triad you get the so-called dominant 7th chord.

When guitarists talk about '7th chords' as in 12-bar blues etc, then they mean chords with the flat 7th.

Major 7th chords are written as Cmaj7, Dmaj7 etc., but the flat 7 or 'blues' 7th is written simply as C7, D7 etc.

So for a major 7th 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 7th chords you could double up on the root, 3rd, 7th or 5th.
Take a standard 7th chord, E7:


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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