AMT on dom7 chords

[guitarjazz]

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Hmm.

George used to always say that they Concept gives you lots of possibilities!

[guitarjazz]

I haven't checked your work against the chart. There is a lot of redundancy especially when dealing with the aux scales. When I think of C7 I think mostly of of Bb Lydian, Db lydian, and E lydian. There are other ways to expand on this, inside and outside the Concept , no pun intended.

[chespernevins]

P/AMT..LT...Most Ingoing Principal Scale on C7
II.........Bb...Bb Lyd
+V.......E.....E Lyd Aug
VII.......Db...Db Lyd Dim
I..........C.....C Lyd b7
+IV......F#...F#Lyd b7
III........G#..G# Lyd Aug

Hey Joe. These chord categories look good. You're certainly correct about II, +V, VII, I, and +IV. I treat a 7th chord on Lyd Aug III like a conceptual modal genre, instead of vertical, and in fact, chart A lists Lyd Aug III as a I chord over III, and not as a 7th chord.

IV.........G....G Lyd Aux Dim
VI.........Eb...Eb Lyd Aux Dim Blues
bVII......D....D Lyd Aux Aug
bIII.......A....A Lyd Aux Dim Blues

After looking at Chart A he seems to have not included a few of those himself, namely my last 4 entries:
IV (G Lyd Aux Dim), VI (Eb Lyd Aux Dim Blues), bVII (D Lyd Aux Aug) and bIII (A Lyd Aux Dim Blues).
Why?

I think this is because of the focus on chord families. There aren't chord families on degrees IV, bVII, and bIII, and VI is primarily a minor chord family, so I think Aux Dim Blues VI is seen as a diminished scale coloration of minor.

I think that the Lydian Tonic Interval figures into this. The Aux Dim Blues VI is going to have C, the chord root, and Eb, the LT, which suggests a minor chord much more strongly than it does a 7th chord.

Maintaining the quality of the chord family doesn't seem to always hold true though. For example, he lists some 7th chords on +IV, which is primarily a min7b5 category. Either of these chord types seems to gel with the Lydian Tonic Interval.

The other thing I noticed about my list is that there are 10 possible LTs on C7, the only 2 omissions being the two "avoid-notes" F and B.

But if I include the horizontally oriented scales in my list it will expand so as to include the F as an LT as well (but not the B).

P/AMT..LT...Most Ingoing Principal Scale on C7
V.........F.....F Major

Horizontal scales are not considered chord producing scales, so I don't think there's really a Major V category.

[chespernevins]

1. I realize that the right hand side of Chart A treats all PMG III chordmodes as being inversions of PMG I chordmodes, but he himself also lists III as an AMT for both II and +V chordmodes on the left hand side.

Very good point.

He does list III as a vertical alternative to II and +V. I kind of forgot that, but I have been aware in the past - and am now reminded - that I am taking artistic license considering LA III (Major b7) as a CMG.

I just happen to like considering the Mixolydian b6 as one of my horizontal scales. Also, C Lydian (Aug) is flat-lying to an E Major triad, so it has some charactaristics of the CMGs.

On chart A, GR lists III as a horizontal alternative to VI minor, and this is consistent with what the book says about conceptual modal genres, starting on p. 116 - that there is a minor triad on degree III. So at least the book is consistent with Chart A.