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Old 12-07-2017, 11:34 AM   #1
zanshin777
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Default Enharmonic Dominant Modulation

https://youtu.be/BThitegbIxk?t=1013 (Pinpointed Link)

1) I don't get the chord progression. (4-6-4 and 1-6-1) What does he mean?

2) Is Enharmonic Dominant Modulation is started with German Augmented 6th chord which is built on the 6th degree of the first key? As you see on the second example Ab is 6th on the first key;

Chord Prog :

IV VI iv (First Key)
Fm Abaug6 Db
iii V i (Second Key)

Last edited by zanshin777; 12-07-2017 at 11:55 AM.
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Old 12-09-2017, 04:01 PM   #2
JonR
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Quote:
Originally Posted by zanshin777 View Post
https://youtu.be/BThitegbIxk?t=1013 (Pinpointed Link)

1) I don't get the chord progression. (4-6-4 and 1-6-1) What does he mean?

2) Is Enharmonic Dominant Modulation is started with German Augmented 6th chord which is built on the 6th degree of the first key? As you see on the second example Ab is 6th on the first key;

Chord Prog :

IV VI iv (First Key)
Fm Abaug6 Db
iii V i (Second Key)
When he says "four six four" I think he means a IV in 2nd inversion, which is called "6/4" in figured bass.
However, that's not what he is playing. His Fm (iv in key of C minor) is voiced Ab-C-F, so it's first inversion (plain "6" in figured bass) not 6/4.

Then he plays the "German 6th" chord (a type of augmented 6th chord) which would normally resolve to the V. I.e., in this case Ab7 to G. (It's called "augmented 6th" because of the interval from Ab-F#, which resolves outwards to the G-G octave.)

Then he says "one six four" and this time he plays it right: Cm/G (2nd inversion Cm), which is what's called a "cadential 6/4" in classical harmony. He follows that with the convention classical cadence > a root position G and a root position Cm.

He then says "4 6 4" again wrongly (playing a "IV6" chord, not a "IV6/4").

He's over complicating it really - at least for a pop-rock-jazz listener. In a minor key, a bVI7 chord is pretty common, and we don't need to call it a "german 6th", nor do we need to refer to inverted chords in figured bass language (which is obviously confusing in speech because of all the different numbers involved: roman numerals, inversion numbers and maybe chord extensions)!

I.e, anyone playing blues or jazz in C minor will come across an Ab7 chord pretty often. Normally it goes to G (in true classical style), but it's easy to see that Ab7 is also the V7 in Db major, so it could equally go there.

It's the "tritone sub" principle, basically. Any dom7 can be replaced with one a tritone away. Ab7 can lead to either G or Db, wherever you find the G or the Db.
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Old 12-11-2017, 11:55 AM   #3
zanshin777
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Is Enharmonic Dominant Modulation should be made with the German Augmented 6th chord built on 6th degree like here?

Chord Prog :

IV VI iv (First Key)
Fm Abaug6 Db
iii V i (Second Key)[/QUOTE]
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Old 12-13-2017, 10:33 AM   #4
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Quote:
Originally Posted by zanshin777 View Post
Is Enharmonic Dominant Modulation should be made with the German Augmented 6th chord built on 6th degree like here?

Chord Prog :

IV VI iv (First Key)
Fm Abaug6 Db
iii V i (Second Key)
It's not so much "should" as "can".

Augmented 6th chords are always (or rather conventionally) built on the bVI degree, and always resolve to V. Conventionally in minor keys too, because the b6 degree is diatonic. They arise from a resolution of the b6 scale degree down to the P5, while at the same time a chromatic #4 is introduced to resolve upwards to the 5th above. The interval between b6 and the #4 above is an "augmented 6th" (half-step bigger than major 6th).

The augmented 6th triad is completed with the tonic note. So (in key of C minor) the chord would be built Ab-C-F#. The plain triad is the "Italian 6th". The "French 6th" adds the 2nd scale degree (Ab-D-C-F#), while the "German 6th" adds the 3rd scale degree (Ab-C-Eb-F#).

The "enharmonic" element is seeing F# as Gb, so the German 6th chord becomes a standard Ab7. And as such it can be used as a V7 chord to go to Db major (or C# minor come to that).

But you can also describe a jazz tritone sub as an "enharmonic dominant modulation". Ab7 can go to G (major or minor), wherever you find that G (or Gm) chord, because its tritone is enharmonic with the tritone in the normal V7 chord (D7).
As with the German 6th in C minor, it derives from the equivalence between F# and Gb.
In key of G, the V7 (D7) has C and F#.
In key of Db, the V7 (Ab7) has C and Gb.

But in this case the resolution is different. The augmented 6th resolves one way: by moving outward to the octave (Ab-F# > G-G). Its enharmonic equivalent, the minor 7th, resolves the other way, to a major 6th (Ab-Gb > Ab-F, 5th and 3rd of Db).

The tritone C-F# (augmented 4th) resolves outward to a minor 6th B-G (3rd and root of G major). The tritone C-Gb (diminished 5th) resolves inwards to the major 3rd Db-F (root and 3rd of Db).
But of course F# and Gb are exactly the same sound - which means D7 and Ab7 can both resolve to either G or Db.
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Old 12-15-2017, 09:58 AM   #5
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Thank you very much for your detailed answer JonR.
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