Watch the Other Chord Types online guitar lesson by Fareed Haque from Jazz Rock Workshop
sure you play this on the guitar and SEE it - don't just take my word for it. Verify this for yourself SLOWLY and CAREFULLY so it makes sense to you.
- Ab7b9 is Ab-C-Eb-Gb-Bbb (A natural), right?
- A dim 7 is spelled A-C-Eb-Gb, right?
- A dim 7 A-C-Eb-Gb is the same as C-Eb-Gb-Bbb (A natural) Ab7b9 with NO ROOT, right? Right!
- And since A dim 7 = C dim 7 = Eb dim 7 = Gb dim 7 (remember since all diminished 7 chords are built from minor third intervals, all four diminished chords above are spelled the same)
Ab7b9= A dim 7 and C dim 7 and Eb dim 7 and Gb dim 7
BUT also if
Ab7b9 = A dim 7 then
B7b9 = C dim 7 and
D7b9 = Eb dim 7 and
F7b9 = Gb dim 7 right? Right!
So check it!
A dim, C dim, Eb dim and Gb dim are all spelled A, C, Eb, Gb
Ab7b9 is spelled Ab + A, C, EB, GB
B7b9 is spelled B + A, C, EB, GB
D7b9 is spelled D + A, C, EB, GB
F7b9 is spelled F + A, C, EB, GB
Another way to see this is to play any voicing of a diminished chord and lower each note by one half step. Since each note of the dim chord can be the b9 of a dom 7 b9, then lowering each note by a half step should create a dominant chord. Let's see if that works:
Lets try C dim on the middle 4 strings spelled from low to high C-F#-A-Eb.
Lower the C a half step and YES! You get a B7 chord
Lower the F# a half step and YES! You get an F7 chord
Lower the A a half step and YES! You get an Ab7 chord
Lower the Eb a half step and YES! You get a D7 chord
So what does all this mean?
Well, I'm not telling you, it's important for you to figure it out for yourself. I will, however, give you a clue. Three pentatonics from Am – Am, Em and Bm – on Ab7b9 (and A dim 7)
Then three pentatonics from Cm – Cm, Gm, Dm – on B7b9 (and C dim 7)
And three pentatonics from Ebm – Ebm, Bbm, Fm – on D7b9 (and Eb dim 7)
And three pentatonics from Gbm – Gbm, Dbm, Abm – on F7b9 (and Gb dim 7)
Hey man that's not fair! That's all 12 pentatonics!
And since all those chords are related, you could, in theory, play any one of the 12 pentatonics over any one of the 8 chords above. In theory, yes you could, but in practice, the further you get from home, the "outer" or more dissonant (or just plain bad), it's going to sound. So use your ears and find what works for you.