Hi, carrying on from the last blog. I'm going to explore Transformational triad theory as applied to 7th chord quality extensions, (Major 7 is explored in the previous blog, Riemannian Reimannian).
Namely mi7 , dominant 7s, and mi7b5s. I'd just like to say that transformations in upper structure triads if they apply, do sound pretty good to me. Something a little new and fun to do.
We apply R. L. moves outline in previous blogs first to mi7s. The application of (P.) will change the basic 7th chord quality and so won't be used in the mi7 chord. The scale-tone triads use will be from the Cmi7—dorian mode.
a) The Cmi7: transforms the Cminor triad Cmi—Ab/C (L.) = Ab/Cmi7... has uses as an Ab major chord inversion.
Cmi—Eb (R.) = Cmi7 and of course works like a Cmi7.
Going on to the next available triad up a third in Cmi7 (Dorian has the most available triads in it) being Eb, transformations are applied to it over the Cmi7 chord. Eb(/Cmi7) = Cmi7.
b) Applying transforms to Eb(/Cmi7):
Eb(/Cmi7) — Cmi(/Cmi7) R. = just Cmi7.
Applying L. to Eb(/Cm7) i.e. Eb—Gmi both over Cmi7 creates a Cmi9 chord.
Going up a third in the C dorian scale the triad built on the 5th of Cmi is Gmi. Remembering that all these exercises are over Cmi7, we now apply transformations of Gmi(/Cmi7):
c) The Gminor(/Cmi7) triad transforms to:
Gmi—Eb (L.) and Gmi—Bb (R.) N.B. that (P.) is not used as it will change the basic quality of the chord in question.
Gmi/Cmi7 = Cmi9, Eb/Cmi7 = Cmi7 (still a useful move), Bb/Cmi7 = Cmi11 a new chord extension chord.
d) Going up another 3rd of the C dorian scale the triad built on Bb(/Cmi7) should transform to create a cool juxtaposition of Cmi7 quality extensions.
The useable transforms (in Cmi7) of Bb are: Bb—Gmi (R.), and Bb—Dmi (L.). If we put those transforms over Cmi7:
Bb/Cmi7 = Cmi11,
Gmi/Cmi7 = Cmi9,
Dmi/Cmi7 = Cmi13(11, 9)
These can be played directly or as transformations of Bb/Cmi7 i.e. Bb/Cmi7–Dmi/Cmi7; Bb/Cmi7—Gmi/Cm7 for some fun color interaction in a minor 7th chord.
e) Going up another 3rd of the C dorian, is the chord Dmi(/Cmi7) which creates a Cmi13.
The transforms of Dmi(/Cmi7) are: Dmi—Bb (L.), and Dmi—F (R.).
Over Cmi7 these transforms become:
Dmi/Cmi7 = Cmi13(11,9)
Bb/Cmi7 = Cmi11.
f) The next C dorian scale-tone triad is F which has only one usable transform: F—Dmi. It has the transform F—Ami but Ami does not fit into the C dorian scale. The F—Dmi (R.) / Cmi7 can be used of course.
Other locations of minor 7ths chords in a major scale: iii Phrygian and vi Aeolian can be explored in a similar way: There will no doubt be various choice that will be interesting but less choices in these scales than the dorian scale allows.
I'll put some music graphics up next week to further clarify.
In the next blog we'll explore transformations in Dominant chords if any. There are more dominant scales to choose from too..