Every diminished triad is just a half step away from being a Major Triad !

[m1469]

Okay, I know that this may be completely common knowledge for many people, but, I'm sorry, I just think it's SO cool  .

So, I have actually just learned this (not too long ago) in a way that means anything to me, so, you know, it's just exciting !

c# e g 

Move the root down a half step and the diminished chord becomes Major

C E G

Yippeeeeeeeeeeeee !!!

So, I am assumming this can be used as some kind of tool for modulations ... something I want to have a better grasp of.

bye bye !

[m1469]

Okay, so the new major triad can become the Major IV of whatever the new key is, and this movement creates a new vii diminished chord in the context of the new key.

So, c# diminished used to be vii dim in the context of D Ionian --

c# e g

move the root down half a step

C E G

becomes IV in the key of G Ionian -- subtracting one of the sharps (c#) within the key signature -- leaving the f# chord without it's former c# -- making that chord diminished which can be used as the leading chord (vii) to G Ionian/Major, which is a 5th down from the original key of D Ionian/Major.


Yippppeeeeeeee

[m1469]

So, if I wanted to modulate upwards by a 5th in a similar way, I guess one would just reverse the chord change and move the root of the IV chord up a half step, making it a dimished vii in the context of the new key !

*goes and tries it out*

So, there probably should be some other kind of ... warning before this sudden chord change, but it doesn't sound that bad to me.  I mean, I don't know all of the rules, but I actually like the way it sounds.  If anything, I guess there should be some way of getting there a little smoother ... but what could be smoother than a change of half a step ?

Of course, I guess one would maybe want to get the V or V7 of the new key in before coming to the new tonic ?

(V in new key would be what in old key ?  *goes to figure it out*)

[m1469]

oh, LOL, the V of the new key would be the tonic (I) of the old key ... ha ha !  IF we were moving down in key sigs by a 5th (what would it be if we were moving up in key sigs by a 5th ?).  Which is actually the same as the secondary chord V/IV in the old key .... meaning ....


*getting lost*

[nolan]

Also, think about the fully diminished 7th chord. For example, C# E G Bb.

Lower the root a half step and you have a Mm7 chord, C E G Bb.
Lower the third a half step and you have another Mm7 chord, Eb G Bb Db (enharmonically respelled and inverted).
Lower the fifth...F# A# C# E.
Lower the seventh...A C# E G.

The fully diminished seventh sliding to a dominant seventh in the new key is a great way to modulate.

[m1469]

Also, think about the fully diminished 7th chord. For example, C# E G Bb.

Lower the root a half step and you have a Mm7 chord, C E G Bb.

Okay, I have to take this a bit at a time ...

So, since that would be creating a Mm7th chord (AKA a dominant 7th, right ?) would it be better then to think of this new chord as the V7 in the new key rather than the IV like I had previously mentioned about the triad ?

I mean, actually changing where one might modulate to.

[nolan]

Code: [Select]

So, since that would be creating a Mm7th chord (AKA a dominant 7th, right ?) would it be better then to think of this new chord as the V7 in the new key rather than the IV like I had previously mentioned about the triad?
Yep...depending on the context (if the passage actually modulates) and how the new chord resolves, I would think of it as V7.

[opus10no2]

 

[daniloperusina]

Actually, a diminished chord is, not one, but four dominants! In disguise..

C# E G Bb works as a dominant seventh to:

Dmajor/minor, Fmajor/minor, Abmajor/minor & Bmajor/minor.

In this context, it is also known as dominant 7th with flattened 9th & without the root

This also determines the "spelling" of the notes, i.e C# or Db.
For example, if it leads to Dmajor/minor, it would be a A7b9(without A), and containing the above notes.

If however it would lead to Abmajor/minor it would be a Eb7b9(without Eb), and the notes would be Db Fb G Bb. Same notes, different names..

[daniloperusina]

m1469, I get a bit confused
I have to sort this out, at least for myself:

So, c# diminished used to be vii dim in the context of D Ionian --

c# e g

Or 3/4 of A7

-- leaving the f# chord without it's former c# -- making that chord diminished which can be used as the leading chord (vii) to G Ionian/Major, which is a 5th down from the original key of D Ionian/Major.

Or 3/4 of D7
(G is subdominant of D - subdominant means 5th down, as opposed to dominant, 5th up)

.. and move the root of the IV chord up a half step, making it a dimished vii in the context of the new key !
...
Of course, I guess one would maybe want to get the V or V7 of the new key in before coming to the new tonic ?

That's exactly what you are doing! You use this chord sequence: Gmajor - Cmajor - aminor7  - Dmajor, but substitute aminor7 for A7 (C# E G) and make it the dominant7th of the dominant..

V in the new key is a II in the old key, with raised third.

I think the diminished triads that you use here are dominants without the roots.
But without both the root, as well as the flattened 9th, there's a bit of ambivalence.

[jlh]

If you lower the root in a dim triad it will always be Major, but if you raise the 5th in a dim triad it will always be minor...

[m1469]

I am still going to deal with only triads for the time, since it helps me cope.

Let's say we were originally in D Ionian (two sharps). 
We change the diminished triad c# e g to  C Major by moving the root down a half step and we get : 

CEG

This could be I or IV or V in the new key, depending on which key we move to (if we consider only the naturally found, Major triads in the Ionian scale). 

I in C Ionian
IV in G Ionian
V in F Ionian

No matter what, another step needs to be made (another chord formed) to establish a new tonality (even if we wanted to actually move to C Ionian, since tonality wasn't *really* established just by creating this chord once).

So, let's say I wanted to go to "C" -- I could go from this new C Major chord to G7 and then back to C ?  Would that sound like we have actually arrived somewhere new, or would more be needed ?  It actually sounded convincing to me (but I only did a few chord changes and wasn't improvising or anything).

If I wanted to go to G Ionian, the C Major chord could act as the IV of that scale -- I know I would want to make it to V7 of the new key (D7) before trying to claim I have actually modulated to a new key.  I could go C Major, D7, G Major (in whatever inversion sounds best).  It also seemed okay to me.

If I want to go to F Major, C Major is already acting as V of that key, but I would probably want to make it a V7 to really establish a true modulation.  So, I would go C Major, C dom 7, F Major.  It seemed okay to me as well.

So, we could move from the key of D Ionian to C Ionian.  We could move from D Ionian to G Ionian, or from D Ionian to F Ionian all by way of changing the c# dim triad to C Major and then going from there. 

I know that thinking of the C chord as V of the new key seems "better" but, the movement from the key of D to F seems less likely (relationship of a third with the key signature change of 2 sharps to one flat) than the movement from the key of D Ionian to G Ionian -- with a circle of 5ths relation and a key signature change of 2 sharps to 1 sharp.  The latter seems more likely and smooth.

What do ya' think ?

[m1469]

Also, think about the fully diminished 7th chord. For example, C# E G Bb.

Lower the root a half step and you have a Mm7 chord, C E G Bb.
Lower the third a half step and you have another Mm7 chord, Eb G Bb Db (enharmonically respelled and inverted).
Lower the fifth...F# A# C# E.
Lower the seventh...A C# E G.

The fully diminished seventh sliding to a dominant seventh in the new key is a great way to modulate.

Okay, I read through this again last night and I could digest it a bit better  .  So, with all of these examples, according to whatever dom7 we have made it, that would indicate where we could go next ?  Let me see :

C E G Bb -- dom7 of F Ionian

Eb G Bb Db -- dom7 of Ab Ionian

F# A# C# E -- dom7 of B Ionian

A C# E G  -- dom7 of D Ionian (which is where we hypothetically were, actually.  So, in this case we would only have done something "colorful" and wouldn't have actually changed keys).

This is very cool.

[m1469]

Actually, a diminished chord is, not one, but four dominants! In disguise..

C# E G Bb works as a dominant seventh to:

Dmajor/minor, Fmajor/minor, Abmajor/minor & Bmajor/minor.

In this context, it is also known as dominant 7th with flattened 9th & without the root

This also determines the "spelling" of the notes, i.e C# or Db.
For example, if it leads to Dmajor/minor, it would be a A7b9(without A), and containing the above notes.

If however it would lead to Abmajor/minor it would be a Eb7b9(without Eb), and the notes would be Db Fb G Bb. Same notes, different names..

I am not sure I understand this, exactly.  I DO notice that the keys you have said it acts as a dom7 to are the same ones that I posted about just above, so I can see that there is some kind of common thought.  But, you are suggesting that we don't need to change the chord's form at all (no note alterations), and instead think of it as a dom7 chord with a flatted nine, minus the root ?  I can get this intellectually but I will need to play with it to really have it mean something for me.

But, thinking of it in this way, whose music or what style would we typically find this in ?  I would think we would not see this too much before Chopin or beyond ... but maybe even Mozart and those guys employ this sometimes ?

[m1469]

m1469, I get a bit confused
I have to sort this out, at least for myself:

So, c# diminished used to be vii dim in the context of D Ionian --

c# e g

Or 3/4 of A7

What do you mean by 3/4 ?  Do you mean 3 out of 4 of the notes of an A7 chord ?

-- leaving the f# chord without it's former c# -- making that chord diminished which can be used as the leading chord (vii) to G Ionian/Major, which is a 5th down from the original key of D Ionian/Major.

Or 3/4 of D7
(G is subdominant of D - subdominant means 5th down, as opposed to dominant, 5th up)

Okay, so again it's 3 out of the 4 notes found in the D7 chord ?  And, it would be called subdominant vs dominant since it's a 5th down and not up.  I think I knew that at one time, but it makes a lot more sense now as to how subdominant gets its name (is that why it's called this ?).  I had orginally learned that it was called subdominant (the IV chord was) because it lives below V -- but, that's not the reason ? 

If we were talking strictly in terms of scale degrees, and not chords, the fourth also being labeled as "subdominant" -- would that also imply the same thing ?  It is called that because it is a 5th DOWN from tonic ?

.. and move the root of the IV chord up a half step, making it a dimished vii in the context of the new key !
...
Of course, I guess one would maybe want to get the V or V7 of the new key in before coming to the new tonic ?

That's exactly what you are doing! You use this chord sequence: Gmajor - Cmajor - aminor7  - Dmajor, but substitute aminor7 for A7 (C# E G) and make it the dominant7th of the dominant..

V in the new key is a II in the old key, with raised third.

I think the diminished triads that you use here are dominants without the roots.
But without both the root, as well as the flattened 9th, there's a bit of ambivalence.

I am going to need to come back to this part in order to truly sort it out ... hee hee.

[m1469]

If you lower the root in a dim triad it will always be Major, but if you raise the 5th in a dim triad it will always be minor...

Well, of course given the nature of the diminished triad (two, stacked minor thirds), this makes *complete* sense.  I should'a thought of that but I didn't get there yet ... LOL !  So, given this, I guess it opens up a whole other field of possibilities in terms of potential modulations !

[daniloperusina]

I've also always thought sub-dominant means below the dominant. Just recently I was told that the person who invented the names actually meant dominant=5th up; subdominant=5th down.

Not that I think it matters a great deal

Yes, 3/4 of A7 meaning one note missing.

I think the diminished seventh chord was used most frequently before the romantic era. Bach and Mozart uses it a lot. For Beethoven, one could perhaps say it's his signature chord. You know the development section of Moonlight, mvt1? The part where he climbs up and up and reaches the highest note of the movement? That's a series of diminished seventh chords played as arpeggios.

The romantics, to avoid sounding like Beethoven, I think shunned away a bit from using the diminished seventh.

A regular dominant with flattened 9th, though, was a particular favourite of Schumann's. Kinderszenen, for example, is full of them!

[daniloperusina]

I tried your progression:
Dmajor - C#dim - Cmajor - C7 - Fmajor

This is, of course, a modulation. But you haven't established Fmajor as a new key. the Fmajor simply sound too resteless.

Even adding one more dominant:

Dmajor - C#dim - Cmajor -C7 -Fmajor - C7 - Fmajor

..makes it only slightly more at ease. Still, the Fmajor begs to be modulated away, for example:

Dmajor - C#dim - Cmajor - C7 - Fmajor - C7 - Fmajor - - Fmajor - A7 - Dminor - E7b9(without E, = D F G# B) - Dmajor/A - A7 - Dmajor.

If you play that, you'll hear how the Dmajor at the end sounds perfectely stable, even though you just came from Fmajor.

[steve jones]

Diminished triads and 7ths are amazingly useful chords, substituting dominant chords, harmonizing chromatic passages, tonicizing / modulating as well as in none functional series'. Being symetrically, you can have loads of fun inverting them and messing around. Chopin did this to great effect in his Etude Op 10 No 3, where he figures chromatically descending / ascending diminished chords to create wonderfully dissonant passages.

If you are interested in diminished chords, I would recommend checking out the octatonic scale. This is really gem! It builds diminished chords on every degree. But it facilitates minor third false progressions, tritone root movements, all kinds of wonderful sounds. Scriabin used it for his 6th sonata to great effect. But you find nuggets of it in earlier works. I noticed it being used in Chopin Op 10 No 9 (although Chopin maybe have consciously used the scale).

SJ

[ramseytheii]

Diminished triads and 7ths are amazingly useful chords, substituting dominant chords, harmonizing chromatic passages, tonicizing / modulating as well as in none functional series'. Being symetrically, you can have loads of fun inverting them and messing around. Chopin did this to great effect in his Etude Op 10 No 3, where he figures chromatically descending / ascending diminished chords to create wonderfully dissonant passages.

If you are interested in diminished chords, I would recommend checking out the octatonic scale. This is really gem! It builds diminished chords on every degree. But it facilitates minor third false progressions, tritone root movements, all kinds of wonderful sounds. Scriabin used it for his 6th sonata to great effect. But you find nuggets of it in earlier works. I noticed it being used in Chopin Op 10 No 9 (although Chopin maybe have consciously used the scale).

SJ

The octatonic was a favorite of Bartok's, and Liszt also used it.  It comes up several times in the "Totentanz," comes up generally when a lot of dminished seventh chords are being used.

Walter Ramsey

[steve jones]

The octatonic was a favorite of Bartok's, and Liszt also used it.  It comes up several times in the "Totentanz," comes up generally when a lot of dminished seventh chords are being used.

Walter Ramsey

The Totentanz is an absolutely astonishing piece. Love it! But I think Korsakov is reported to have been among the first to use this scale to any great extent in romantic music. Eitherway, it is a fantastic scale.

SJ