Diminished Scale Theory

Jazz Theory Discussion
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Since you posted this, @Jovino I’ve been studying your lessons on the diminished and the triads that can be used with it and with the dominant seventh. Before Covid came along I had a local jazz keyboardist as teacher who used the term “polyphonic dominants”, describing the major triads that could be added on top of the dominant based on the flat 6, flat five, flat 3 and flat 2. The last two are of course also the flat 6 and flat 5 of the subdominant and vice versa, so it works with both dominant and subdominant. He didn’t mention minor triads at all*. Does this fit in with the way you view dominants and diminished chords? Do the minor chords you describe come in when you change the underlying dominant from (say)c7 to a “rootless” edim = cb9 ?? I suppose I’m looking for a “formula” that quickly lets me work out the possibilities in a practical way.

*edit - this might just be because covid intervened in the lessons.

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Hello George,
Thanks for your question. The possible triads will be different depending on the kind of chord. Even with dominant 7th chords, it will depend on what kind of 9th and 13th the chords have. if you can be more specific about which chords you are referring to, I will tell you which triads can be used. Of course, the triads can be extracted from the scale used in the chord, such as the auxiliary diminished scale for 7(#9) chords, altered scale for 7(#9b13) and so on. I hope this helps. Best, Jovino

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