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Secondary Dominants - Diminished Chords.


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#1 Happyhacker

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Posted 28 August 2017 - 14:47

I am trying to understand the following description:

 

Diminished Chords Functioning as Dominants

 

"Diminished 7th chords may function as rootless 7b9 chords. The diminished 7th chord occurs naturally on the 7th step of harmonic minor tonality with the label viio7. The same label is used when diminished chords function as secondary dominants.

 

An important difference in the analysis of a diminished 7th chord is that in order to be considered a functioning secondary dominant, it must be followed by one of it's intended targets: a diatonic chord half a step above any of it's tones (any tone of a diminished 7th chord may be thought of as it's root).

 

Motion of Diminished chords with secondary dominant function in C major:

 

viio7/ii (C#o7) target is: iim7 (Dm7)."

 

The text goes on to list the four other V - I resolutions in that key. I do not understand how they have arrived at C# but must be something to do with the first sentence of that text. can anyone explain this? I am a beginner at piano Jazz and do a lot of theory study to go with it so go easy if you can. Thanks.


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#2 Hildegard

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Posted 02 September 2017 - 05:38

Secondary dominant chords are dominants of another chord, rather than of a key. However, to understand them, think in terms of a key.

Think of the key of D minor. The author has made a diminished 7th on the leading note (the 7th degree of the scale), which is C#.
Diminished 7th chords consist of minor 3rds piled upon each other, so the chord is C#-E-G-Bb.
Because this is followed by a chord of D minor it sounds like a dominant minor 9th (A-C#-E-G-Bb) of D minor, but without its root (A).

Now switch back to thinking in terms of chords rather than keys.
The example is not actually in the key of D minor. It is a (rootless) V9 chord that resolves onto chord ii of C (i.e. the chord of D minor).


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#3 jazzrob

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Posted 12 September 2017 - 13:57

In line with Hildegard, but going back a step, I was taught (and I now teach) the importance of understanding what a diatonic chord is. In doing so you learn the functionality, and nature of them.

 

A secondary dominant is a dom7 of a Diatonic chord. Simple as that really.

 

Eg, In C maj, Dmin is chord II- (IIm7). The secondary dom of Dmin is A7 (labelled as V7/III).

 

The incomplete Dom7(b9) chord that your'e looking at is not something that I would like to cover until the secondary dominants are understood. Diminished chords can function different ways (as your text mentioned).

 

Rob


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#4 Dharma

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Posted 24 September 2017 - 12:57

Wizardry.
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#5 Kai-Lei

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Posted 26 September 2017 - 20:23

....deleted....software can't manage inflexion signs. 


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#6 Kai-Lei

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Posted 14 October 2017 - 12:34

FOR GOODNESS SAKE! 

 

WHY CAN'T THIS SITE SHOW CONVENTIONAL FLAT AND NATURAL SIGNS? 

THE SOFTWARE CHANGES ALL TO "?" WHICH MAKES A MESS OF THE EXPLANATION.  I'LL HAVE TO DELETE THE POST ABOVE BECAUSE IT BECOMES INCOMPREHENSIBLE.  

 

CAN'T THIS BE PUT RIGHT?


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#7 Ilewydh

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Posted 14 October 2017 - 13:08

Not sure if this is going to work but I had to copy and paste from Word a (b) and an (n) in the font Tamburo.  

 

Not the ideal solution but something, IF it works!

 

b  n


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#8 Kai-Lei

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Posted 17 October 2017 - 21:20

Thank you. But it's still a surprise where these signs would often appear that the site can't handle them !


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