dim, 7 b9 and m7 b5

I´m collecting chord equivalences and this is the part of the table from 7b9 chord:

7 b9:
1 3 5 b7 b9
C E G Bb Db

dim7 b13:
1 b3 b5 b6 bb7
E G Bb C Db

dim7:
1 b3 b5 bb7
G Bb Db E

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Quote:
Originally Posted by Jazzaluk
Pat Martino's book 'The Nature of Guitar" delivers a very eloquent way of looking at diminished chords and how they relate to Dominant 7th.

Take any diminished 7th chord (a stack of minor 3rds) and pick one note and lower it by a semi-tone. The result will be a Dominant 7th chord with the root of the note that was lowered.

For example:
take G#dim = G#, B, D, F
Lower G# to G gives G,B,D,F = G7th
Lower B to Bb gives G#,Bb,D,F = Bb7th
Lower D to Db gives G# (Ab),B, Dd,F = Db7th
Lower F to E gives G#,B,D,E = E7th

If you apply this to one position on the guitar and analyse the resulting chord forms you will see that each 7th chord represents a unique inversionn that basically conforms to one of the five guitar positions in the CAGED system.


G#dim.....G7....Db7...Bb7...E7
--4-------3-----4-----4-----4--
--3-------3-----2-----3-----3--
--4-------4-----4-----3-----4--
--3-------3-----3-----3-----2--
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As you probably already know, the diminshed chord form is symetric on the neck which means that if the same chord form is moved up in minor third intervals (3 frets), all the notes of the diminished chord are repeated (in a new inversion). So, using this characteristic, it is possible to quickly construct new inversions of these same 7th chords by moving diminished chord form 3 frets and applying the same Martino rule. Move the form again and more inversions are revealed. This will work for any of your favourite diminished chord forms.

Of course this is not music but merely another piece of the puzzle that may help open up the neck a bit.

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Yes, very interesting undeed.
By the way, curiously, if we raise any note a half step we get the half diminished chord (m7 b5 - hd):


G#dim......Bhd....Dhd....Fhd...Ahd
--4-------5-----4-----4-----4--
--3-------3-----3-----4-----3--
--4-------4-----4-----4-----5--
--3-------3-----4-----3-----3--
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I think this chord may be used:
-In major tonalities, as the 7th degree: an extention/substitution of the dominant (V):
G B D F -> B D F A

-in minor tonalities, as the 2nd degree: preparation or substitution of the dominant:
D F Ab C -> G B D F
Ab is the b9 of the dominant, and C is the 11th, so the II m 7 b5 is basically a DOM 7b9)

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