#1
How is this not just a Major minor 7th chord? I mean it's not spelled as a 7th chord, it has the augmented 6th but say F A C D# gets you a Gr6 chord, but if you call the D# an Eb you have a Mm7 chord. I know intervals, etc. and it can't be a m7 of F unless it's an Eb. Is it called that because the interval is an aug6 not a m7? That's my guess at least. It obviously sounds like a Mm7 chord.
Earth without ART, is just Eh...
Last edited by metalzeppelin at Jul 22, 2009,
#2
Yeah that's right. And the reason the interval is an augmented sixth and not a minor seventh has to do with context, function, and how the chord is formed.
Si
Last edited by 20Tigers at Jul 22, 2009,
#3
Yeah, M3 + P5 + Aug6.
So is the only purpose for it for roman numerically analyzing a piece of music because you can't call it a 7th chord with a 6th in it?
Earth without ART, is just Eh...
#4
So in the key of Am you have a i iv V i progression.
Am Dm E Am

For the German 6th take the Dm and make it a Dm7 chord -> D F A C
Am Dm7 E7 Am

Put it in first inversion - F A C D

Then sharp the root note (the D) to a D♯ so that when you move to the E chord the D♯ moves up a semitone into the E while at the same time the F moves down a half step to the E root.

This D♯ increases the tension in the chord because of the internal harmony of the chord and because the D♯ is the dissonant tritone in the key of Am.

Because the tone in question is reached by raising D one semitone (NOT by lowering E by a semitone) it is called D♯. Thus the distance between that F bass and the D♯ is an augmented sixth as opposed to a minor seventh.

Does that help?
Si
Last edited by 20Tigers at Jul 22, 2009,
#5
You could just call the same chord an F7 (F dominant 7th chord) though which is F A C E♭ - enharmonically equivalent with the previous chord. But the above post explains the way in which it would be considered a German6th as opposed to a secondary dominant.

It's all to do with function.

The dominant seventh chord typically resolves with a root movement down a perfect fifth (or up a fourth) while the inherent tritone dissonance is resolves by the third moving up a semitone and the min7 moving down a semitone.

So F7 (F A C E♭ would see the bass move down a P5 (or up a P4) to a B♭ root. Meanwhile the A and E♭ diminished fifth dissonance in the chord is resolved by the A moving down a half step to the B♭ (root of the new chord) while the E♭ moves up a semitone to the F (the P5th of the new chord).

The German 6th resolves in a different way. The bass is resolved by a half step downward movement to the bass(root) of the new chord.
The tritone is resolved in the opposite manner as before. Now the A moves down a half step to the G♯ (the M3 of the E chord) while the D♯ moves up a semitone to the E of the new chord.

Context.

Of course not all dominant7 chords are functioning dominant chords. Sometimes we might have a non functioning secondary dominant which basically means it doesn't resolve in the way outlined above.

Also the German sixth is often followed by an inversion of the tonic before folding into the V chord. So it's messy when you start getting into these kinds of things but what you call it isn't really all that important. If you see how it works that's what you want to take away with you and play with.
Si
Last edited by 20Tigers at Jul 22, 2009,
#6
Ok. (I know how to resolve 7th chords.) So the difference is they resolve differently and the Gr6 has an aug6 and the Mm7 has a m7 basically?
Earth without ART, is just Eh...
#7
Yeah their differences lie in context and function.

They function differently even though they are, enharmonically speaking, the same chord. Thus they can be used as a pivot chord to modulate. The Gr6 in the key of A is also the dom7 chord in the key of B♭.

The Gr6 achieves the same effect as if we had a cycle of fifths progression II7 - V7 - I where the II7 is obviously a secondary dominant in the key of I. A tritone substitution on that II7 yields ♭VI7 which is enharmonically equivalent to the Gr6 in the key I.

For example in the key of A major our II7 V7 I progression would be B7 E7 A. A tritone substitution on the B7 gives us F7 (♭VI7 in the key of Am). This as we have seen already is the enharmonic equivalent of a Gr6 in the key of A.

Both the tritone sub on the II7 chord and the Gr6 resolve to the V7 in the same way described in the last post. - The Gr6 and the TT sub on the II7 are just two different paths leading to the same place.

It's about function resolve and how you got there. Is the chord an inverted altered IV chord - which would make it a Gr6 - or is it a tritone substitution for a II7 - which would make it a ♭VI7 chord. Ultimately it achieves the same effect. But it's worth understanding how it all fits.
Si
Last edited by 20Tigers at Jul 23, 2009,
#8
Ok. Thanks for taking the time to explain it. I don't know if I'll ever actually use a Gr6 chord, but it's nice to know. One other thing. I saw the bVI7 chord in my music book. What does that mean?
Earth without ART, is just Eh...
#9
Wow, this is pretty informative. I'd heard of these chords before and never known what they meant, thanks guys!

@metalzeppelin: the bVI7 chord is the tritone substitutuion for the II7 chord. LIke the bII7 is a tritone substitution for the V7 chord. (right?)
#10
Yeah it's cool stuff. I don't know if I'll ever use them but w/e. I'm also learning Italian 6th and French 6th chords.
Earth without ART, is just Eh...
#11
Quote by metalzeppelin
Ok. Thanks for taking the time to explain it. I don't know if I'll ever actually use a Gr6 chord, but it's nice to know. One other thing. I saw the bVI7 chord in my music book. What does that mean?

Yeah the ♭VI7 appears in my last post too.
One question...
Do you get how tritone substitutions work?

Anyway ♭VI7 means a dominant seventh chord built off a ♭6 in a given key.

So the major scale can be written as 1 2 3 4 5 6 7 and the diatonic chords for the major scale could be represented by roman numerals - I ii iii IV V vi viidim.

If we use a chord that is out of key, such as a chord built off the ♭6 we simply carry the ♭ into the chord name so that it becomes ♭vi or ♭VI. If we build a chord using the ♯4 as a root then the chord might be ♯IV etc.

So in the key of A the 6 is F♯ and lowering that a semitone the ♭6 is F. So ♭VI7 in Am uses F as the root and we build a dominant seventh chord on that root to get F7.
Si
#12
So in practice, why would you label a chord a Gr6 rather than a bVI7? Would this kind of thing only apply in, for example, SATB writing when the two voices actually move in that way (one up a semitone to the root of the V, the other down) or would it be equally applicable in accompaniment in a pop song?
#13
Quote by werty22
So...why would you label a chord a Gr6 rather than a bVI7?
I can't answer that because, I don't know.

My interest is in how the chord works.
Si
#14
Quote by werty22
So in practice, why would you label a chord a Gr6 rather than a bVI7?


I don't think they are in any way the same thing. I may be wrong.

Where does the tritone of the tritone substitution come in? I know it is a b5 or aug 4th, but I don't get where it occurs in the tritone substitution.
Earth without ART, is just Eh...
Last edited by metalzeppelin at Jul 25, 2009,
#15
Quote by metalzeppelin
I don't think they are in any way the same thing. I may be wrong.

Where does the tritone of the tritone substitution come in? I know it is a b5 or aug 4th, but I don't get where it occurs in the tritone substitution.


To clear the air, the very basic idea of a tritone substitution is that a dominant 7th chrd (e.g. a7) can be substituted by another dom 7 chord rooted on the note a tritone away from the 7 chord it is substituting for (here it'd be d#7).
#16
To elaborate even more, the most important notes of a dominant seventh chord are the third and the flat seventh, which form a tritone with one another. For example, G7 contains the notes G B D F. The dominant 7th chord a tritone away from it is Db7, which contains Db F Ab Cb. The notes in bold (the most important notes that define it as a dominant) are shared by both chords (Cb being the enharmonic equivalent to B).