Guide to Chord Formation by Howard Wright (Howard@jmdl.com)
Chapter 6 : 9^{th}s, 11^{th}s, 13^{th}s
6.0 : 9^{th}, 11^{th} and 13^{th} Chords
Once you move beyond
7^{th}s and start adding notes from higher up
the
scale (e.g.
9^{th}s,
11^{th}s,
13^{th}s) there is one very important
thing to remember.
All of these chords must have a 7^{th} in them.
Just as there are 3 types of
7^{th} chord (
7^{th},
min 7^{th},
maj 7^{th}), you end up with 3 types for
9^{th},
11^{th} and
13^{th} chords by simply
adding to the
basic 7
^{th} chord.
To get a 9
^{th} chord, add the 9
^{th} to the (
flat) 7
^{th} chord
To get a min 9
^{th}, add the 9
^{th} to the
min 7
^{th} chord
To get a maj 9
^{th}, add the 9
^{th} to the
maj 7
^{th} chord
To get
11^{th} chords you can
add the 11
^{th} to the 3 types of 9
^{th} chord, but most of the time the 9
^{th} is not needed, so you simply add an 11
^{th} to the 7
^{th} chords to build the 3 types of 11
^{th} chord, and similarly with 13
^{th}s.
If you have a
voicing of a 13
^{th} chord that
also has a 9
^{th} or 11
^{th} in it, then that's fine: it's still a 13
^{th} chord, but most of the time these chords are just a normal 7
^{th} with an added note (9
^{th}, 11
^{th} or 13
^{th})
6.1 : 9^{th}, 11^{th}, and 13^{th} Chords
The
spelling for chords like
C9,
C11,
C13 (i.e. chords built on
C7  so they have a
flat 7^{th} in them) is:

9^{th}: 1^{st}, maj 3^{rd}, 5^{th}, flat 7^{th}, 9^{th}
11^{th}: 1^{st}, maj 3^{rd}, 5^{th}, flat 7^{th}, 11^{th}
13^{th}: 1^{st}, maj 3^{rd}, 5^{th}, flat 7^{th}, 13^{th}
It's worth noting here that the 5
^{th} can be
omitted from the chord.
The
essential notes for C9, C11 and C13 are the
1^{st},
3^{rd},
7^{th} and
9^{th}/
11^{th}/
13^{th}
Guide to Chord Formation by Howard Wright
Reformatted and noded (with permission) by Space Butler
< 6^{th} Chords 
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X/Y Type Chords >