Naming a Diminished Chord

[wolflen]

the function of the chord depends on how its is named..in many cases the diminished is used as a passing chord and named by its bass note..but in many cases it is used in a resolving function..in such I see it as a dominant function and would convert it to a 7b9..

In a progression like this-

F Eb/G Abdim F/A

I would see it as a passing chord function(chromatic) and named correctly..to name it any of its related tones (B D F) would seem out of place

In the example given G7 to Cmi..as bako said the leading tone should determine its name...but it could correctly be named a G7b9 because of its resolving function-G7 G7b9 Cmi as opposed to a passing chord--G7 Bdim Cmi

[bako]

I had a funny experience taking a theory placement test entering college.
I had analyzed a Debussy piano score using chord symbols and slash symbols for inversions.
It was the language that I was familiar with at the time.The teacher administering the test confused by my jazz symbology sent me to meet with the theory department head.

The main thing in my analysis that he took issue with was the way I had named some diminished chords.
He pointed at a chord and asked me what it was. I said Xdim and he said "no it's not".
I looked again and renamed it according to how it was spelled and told him ok, but this is just semantics.
He shouted back at me "No it's not". His point, naming/spelling can be indicative of function.

[Rob MacKillop]

I'd call it a G7b9, as that's what its function is. Function is important.

[Jonah]

I'll second G7b9 rootless - to it makes more sence for jazz functional approach...

But if you really accent F as root in this chord then it will bring in minor plagal cadence sound to the harmony.. in this case it could make sence to call it Fdim... it depends


In classical.. it should be Bdim inversion to be resolved in C minor triad inversion... but I dont see it can make any sence here.


And I would not call it 'passing dim chord' anyway... it's more like a 'leading dim chord'..

[JonR]

I like the Bdim7, leading-tone explanation. Also, if I saw that progression on a chart, I would be thinking of it as G7b9 rootless. And if it were a half-diminished I would think of it as a G9 rootless.

But that wouldn't apply in most jazz sequences.

In terms of derivation, you're right.
vii chord in C minor = Bdim7 (B D F Ab). Dominant function, resolves to Cm, so can be seen as rootless G7b9.
vii chord in C major = Bm7b5 (B D F A). Dominant function, resolves to C, so can be seen as rootless G9.

However, in practice, Bm7b5 is almost never used in that way. If you see Bm7b5 in a chord chart, it's a safe bet it will be followed by E7, and then probably Am. IOW, Bm7b5 is used as a ii chord in A minor - with a subdominant function, not a dominant one. In that sense, it makes more sense to see it as Dm6, or Dm/B - a version of the iv chord. A G bass would be out of place, subverting its A minor ii function.

[JonR]

BTW, there's a couple of other uses of dim7 chords. In fact, there's only 3 possible ways they can be used, seeing as there are only 3 dim7 chords....

The vii leading tone function - as discussed above - is probably the most common and best known.
Any time one of the notes in the dim7 chord (any of the 4) is a half-step below the root of the next chord, then it's acting as a vii leading tone chord. It's originally a minor key move, but used often in major keys too, and very frequently as a secondary chord (vii of any chord in a key other than I).

Use 2 is the "common-tone diminished", where any note of the dim7 is the same as the root of the next chord. This is almost always used before a major chord, usually the tonic, and often between two instances of the tonic. Eg, C-Cdim7-C. So it really is like a fully diminished version of the chord it's resolving to.

Use 3 - the remaining possibility - is where any note of the dim7 is a half-step above the root of the next chord. There's not really a name for this, AFAIK, other than "chromatic passing chord". Commonly it's part of a descending line, maybe between two min7 chords a whole step apart. (Fm7-Edim7-Em7). Sometimes you can think of this usage as the vii of the preceding chord; it often sounds like that. (Eg, Fm7-Edim7 sounds much like Fm7-C7(b9).)

Uses 2 and 3 don't derive from a local key, so enharmonic spelling is anything you like (although it still makes sense to work from the context). You find them quite often in Jobim tunes, and there's examples of #3 in "Night and Day".

[Reg]

Typically there are three types of Dim chord in jazz,
Passing, approach and auxiliary
Passing and Approach generally to a diatonic chord a half step higher or lower. How you spell, voice and voice lead doesn't really matter, your choice... Generally have dominant type of function.
Auxiliary dim have same root as target chord, usually I or V as root and are almost always non dominant, more of an embellishment... common tone or auxiliary dim. chord.

[rintincop]

B° to C, like a rootless G7b9 leading tone approach to C

[rintincop]

Typically there are three types of Dim chord in jazz,
Passing, approach and auxiliary
Passing and Approach generally to a diatonic chord a half step higher or lower. How you spell, voice and voice lead doesn't really matter, your choice... Generally have dominant type of function.
Auxiliary dim have same root as target chord, usually I or V as root and are almost always non dominant, more of an embellishment... common tone or auxiliary dim. chord.

Good explanation. But can you explain the dominant type of function when the approach descends such as with
D-7 C#dim to C (tonic)

[wolflen]

Good explanation. But can you explain the dominant type of function when the approach descends such as with
D-7 C#dim to C (tonic)

ok...as Reg pointed out..the three types (Typically there are three types of Dim chord in jazz,
Passing, approach and auxiliary) passing and approach to a diatonic chord - generally a half step higher or lower..

it could be a dim approach chord..which makes the most logic to me..or convert it to a Gb7b9-no root (Gdim)

[Reg]

Good explanation. But can you explain the dominant type of function when the approach descends such as with
D-7 C#dim to C (tonic)

Depends what the tonic is... and yes most common function would be chromatic....

But when you actually play D-7 to Dbdim7 to Cmaj... It sounds lousy, like a mistake. You can stretch spelling and use blue notes... I mean when playing most jazz tunes... your going to use some type of bII7 or V7 to get to target of Cmaj or Min.

And even if you want a Dom reharm... the C#dim7 would become E-7b5 A7alt and then a II V to target of C? You would be adding a typical chord pattern.

And you cans always use root motion with modal interchange and call it deceptive dominant resolution.

If you change the target... to The D-7... pretty simple... D-7 to A7altered to C whatever... Maybe even like How Sensitive
It's just D-7 to A7alt.... you can just call the C#dim a sub or version of the D-7's V7 chord... pretty easy to see and hear the dominant function in that perspective... anyway, there are lots of choices... you need a tune for reference to really define the functional aspect.

[JonR]

Good explanation. But can you explain the dominant type of function when the approach descends such as with
D-7 C#dim to C (tonic)

Strictly speaking, that's not a "dominant type function".
The only "dominant type" of function a dim7 performs is when rising a half-step (Bdim7 > C).
(A chord leading to a tonic is not necessarily "dominant" in function - only when it can be seen to sub for the actual dominant, V. C#dim7 doesn't have enough in common with G7, even an altered one.)

What you have there is what I call a chromatic passing chord (the third usage for a dim7, after leading tone chord (half-step below target) and common-tone diminished (same root as target).
I kind of agree with Reg it sounds like a mistake - leading to a major tonic - but you do get dim7s descending by half-step when leading to non-tonic minor chords. ("How Insensitive", "Night and Day", etc.)

If C#dim7 can be said to have a "dominant type" function in that sequence, it's relative to the previous chord. C#dim7 is the leading tone chord in D minor. Dm7-C#dim7 sounds a little like Dm7-A7b9. (Even more in How Insensitive, because the melody note is A on both.)

[rintincop]

With "Wave" Bbdim7 acts as a disguised V7b9 of D7 with an A-7 inserted in between (forming its ii V)

| Dmaj7 | Bbdim | A-7 | D7 |
| Gmaj7 | G- | etc

[JonR]

With "Wave" Bbdim7 acts as a disguised V7b9 of D7 with an A-7 inserted in between (forming its ii V)

| Dmaj7 | Bbdim | A-7 | D7 |
| Gmaj7 | G- | etc

Right. Or you could call it C#dim7, which is the diatonic vii chord in D minor, often borrowed for D major. No need to invoke A7b9.

[JKessell]

D#dim7

I'm relatively new to theory but as far as I know you should always name the notes of a diminished chord as flattened versions of what they would have been in the major scale?

So the dim7 chord is defined as 1 b3 b5 bb7 but as this is a sharp chord would that mean I should write the notes as sharps? For example D# F# A C

If I write them as flats I'd end up D# Gb Bbb Dbb. Is that allowed? Shouldn't it be either consistently flats or sharps? I'm guessing the Bbb as well as A would be the augmented 4th?

Very confused, if anyone can enlighten me I'd be very grateful.

[BigDaddyLoveHandles]

It depends on how legit you want to be. Jazz cats often use enharmonic names for notes, and especially with diminished chords, because of that diminished seventh interval.

If you want to be legit:

1. You know it will be D#, F-something, A-something, C-something. Filling in the *somethings to get the right intervals we see:

D# F# A C.

2. If you wanted to start with the enharmonic Eb, it would be:

Eb, G-something, B-something, D-something

and filling that in:

Eb Gb Bbb Dbb

There's no need to mix and match between them.

3. Here's my favourite skill-testing question: what is Cb dim7?

[ColinO]

So the dim7 chord is defined as 1 b3 b5 bb7 but as this is a sharp chord would that mean I should write the notes as sharps? For example D# F# A C

I

That is the part that is not true and which is probably causing your confusion. b signs have nothing to do with it. To make a dim7 chord you are required to lower the 3d and 5th notes by a semitone and the 7th by a whole tone. Actually the "definition" is more accurately a 7th chord constructed by stacking 3 minor third intervals. The accidental signs you use are the tools that are available to you to write that on paper. The accidentals you use depends on the context.

For example, F# diminished according to your approach would have the notes F# A#b C#b and E#bb. Probably not the best way to convey the chord.

[wolflen]

D#dim7

I'm relatively new to theory but as far as I know you should always name the notes of a diminished chord as flattened versions of what they would have been in the major scale?

So the dim7 chord is defined as 1 b3 b5 bb7 but as this is a sharp chord would that mean I should write the notes as sharps? For example D# F# A C

If I write them as flats I'd end up D# Gb Bbb Dbb. Is that allowed? Shouldn't it be either consistently flats or sharps? I'm guessing the Bbb as well as A would be the augmented 4th?

Very confused, if anyone can enlighten me I'd be very grateful.

I consider the dim7 formula 1 b3 b5 6 (double flats/sharps are confusing at best)..in the diminished/augmented/symmetric harmony world they are just a PITA..

...read up on some ways to think about and use diminished scales/chords...in and of themselves they can be very confusing..

some points may make them a bit easier to digest--

there are ONLY three diminished scales (many musicians just use flat notes in dim chords/scales)

C Db D

each scale embeds FOUR diminished 7 Chords

C dim7 Eb dim7 Gb dim7 and A dim7
Db dim7 E dim7 G dim7 Bb dim7
D dim7 F dim7 Ab dim7 B dim7

if you just look at the root notes of all these chords you will notice-they cover ALL 12 notes of the chromatic scale-this will be more valuable information the more you become familiar with how to use diminished chords ( just using all flat notes takes the task of having to think/convert D# to Eb and so on-that way there is only ONE dim chord-not two)

and for me..the most important short cut in understanding diminished chords...the confusing whole step/half step and Half step/whole step issue..some insist they are separate scales--

I disagree..here is the C diminished scale

C D Eb F Gb Ab A B in the whole step half step configuration

here is the C diminished scale starting on the B note

B C D Eb F Gb Ab A -- this is called the half step/whole step config

The notes are the same but the starting point is different..it is NOT a separate scale--Its the C dim scale starting on the B note..Just as starting the G major scale on the F# note would not be called an F# major scale..in using this type of approach you eliminate a lot of confusion and a bunch of "scales/chords" that you already know..if you dig deeper into diminished scale use and theory (symmetric harmony) you will find many chords embedded in the scale..major minor and dominate and altered dominate chords..and a couple of very cool tri tone scales..

hope this does not confuse you more..

[cosmic gumbo]

As usual, context is the answer. If you had a progression in a key, you would have something to base the chord spelling on. I like thinking of dim7 as min6b5.

[bako]

A leading tone diminished is named a half step below it's target.
A common tone diminished by the root of the chord it shares commonality with.
Technically diminished are spelled in 3rds. Example below shows the pitfalls of strict adherence.
Often musicians will use pragmatic adjustment spellings while others spell oblivious to function.
As players, it's our job to make musical sense of it either way.


C Eb Gb Bbb ----------- B# D# F# A

Eb Gb Bbb Dbb -------- D# F# A C

Gb Bbb Dbb Fbb ------- F# A C Eb

A C Eb Gb

-------------------------------------------

C# E G Bb --------------- Db Fb Abb Cbb

E G Bb Db ---------------- Fb Abb Cbb Ebb

G Bb Db Fb

Bb Db Fb Abb ------------- A# C# E G

----------------------------------------------
D F Ab Cb

F Ab Cb Ebb ----------- E# G# B D

Ab Cb Ebb Gbb -------- G# B D F

B D F Ab ---------------- Cb Ebb Gbb Bbb

Be kind to musicians when possible.

[Runepune]

Never got this dim7 thing...It has always been called dim over here, and nothing else Or, I get that it's supposed to indicate the use of that last minor third, but if anything I'd call it a 6. If I didn't know better I would have thought dim7 was a diminished triad + the minor 7th.

[mr. beaumont]

It's a simple question to answer...when is the only time you'd need to write out the notes in a D#diminished chord?

Music school test, or if you're writing instructional material.

In both cases, you...call it Eb dim and never speak of it again

[Doublea A]

D#dim7

I'm relatively new to theory but as far as I know you should always name the notes of a diminished chord as flattened versions of what they would have been in the major scale?

So the dim7 chord is defined as 1 b3 b5 bb7 but as this is a sharp chord would that mean I should write the notes as sharps? For example D# F# A C

If I write them as flats I'd end up D# Gb Bbb Dbb. Is that allowed? Shouldn't it be either consistently flats or sharps? I'm guessing the Bbb as well as A would be the augmented 4th?

Very confused, if anyone can enlighten me I'd be very grateful.

I would say:

D# F#. A. Cb

Because to me you want to see the letter names D. F. A. C


Sent from my iPhone using Tapatalk

[Doublea A]

D#dim7

I'm relatively new to theory but as far as I know you should always name the notes of a diminished chord as flattened versions of what they would have been in the major scale?

So the dim7 chord is defined as 1 b3 b5 bb7 but as this is a sharp chord would that mean I should write the notes as sharps? For example D# F# A C

If I write them as flats I'd end up D# Gb Bbb Dbb. Is that allowed? Shouldn't it be either consistently flats or sharps? I'm guessing the Bbb as well as A would be the augmented 4th?

Very confused, if anyone can enlighten me I'd be very grateful.

And yes I would keep my sharps and flats consistent


Sent from my iPhone using Tapatalk

[matt.guitarteacher]

I would say:

D# F#. A. Cb

Because to me you want to see the letter names D. F. A. C

But C natural as opposed to Cb...