Diminished chord notation question

Subject: RE: Diminished chord notation question
From: Stringsinger
Date: 31 Aug 13 - 06:12 PM

Another point about diminished sevenths. They often take the name of
the key for example in F: an F diminished could take the place of a G7b9 which could lead to Gmin7 and then C7. The theoretical choice would be B dim 7.

Another example, C# diminished seventh which subs for A7b9 could be also
a half-step up from the tonic C going to Dminor 7 to G7,
it could be labeled C Maj, C#o7, D min and G7 (the famous Rhythm changes in jazz based on "I've Got Rhythm" by Gershwin. This in place of C A7b9 Dmin7 G7.

This is based on the infamous I-VI-II-V7 progression. C-A-D-G7

Subject: RE: Diminished chord notation question
From: GUEST,Jack Campin
Date: 31 Aug 13 - 12:11 PM

Hey, M.Ted, wherever you've been for the last couple of years, welcome back.

Subject: RE: Diminished chord notation question
From: Mooh
Date: 31 Aug 13 - 11:44 AM

The realization that flattening any note of a diminished 7th chord results in a dominant 7th chord (or vice versa) was mind blowing to me at the time. Resultant modulations, chord substitutions, and just good old fashioned fun making up chord progressions was so helpful to ears and mind.

Peace, Mooh

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 30 Aug 13 - 05:13 PM

Off the top of my head, if you used an Am or Am7, it wouldn't function as a secondary dominant(which resolves to the Dm), it would just be an extension of the C, which is the tonic, so you need it to be an A7, ergo. It may be an arguable point, in the abstract, but I've seldom run across tunes where both a minor chord and a dominant seventh could be swapped out.

Subject: RE: Diminished chord notation question
From: Artful Codger
Date: 30 Aug 13 - 06:08 AM

M.Ted: No, the natural dominant in minor mode is minor; the major dominant is a substitution, occurring historically later--a frequent one nowadays, but an alternative nonetheless which has only partially supplanted the original minor dominant. It's not unusual to find pieces using both, in the same way one finds both minor II and major II (VofV) chords in major mode.

Subject: RE: Diminished chord notation question
From: Stringsinger
Date: 29 Aug 13 - 11:34 AM

Another point about the diminished seventh chord. The root of the chord can be defined by the chord that it goes to next up a half step. Take four notes of the diminished
seventh chord. C#-E-G-Bb. C# moves a half step up to D, the root of the next chord.
A7b9 also goes to D as the V7b9 to I. Now, take E as the root. E-G-Bb-C#. E moves up a
half step to F. But the C# must now be changed to Db which is the b9 of C7b9.
Now, take G as the root. G-Bb-Db-E. But now E must become Fb which is the b9
of Eb7b9 which goes to Ab as the V7b9 to I. Now that leaves the fourth note of the
diminished seventh chords. Bb. (once again the C# becomes Db). Bb-Db-G-Fb. Bb moves up to Cb (not B). It is now a Cb diminished seventh. Gb7b9 is the V7b9 of Cb.

Now, to add to the confusion, each of these chords can be spelled enharmonically
involving double flats and double sharps. C#-E-G-Bb can be spelled Db-Fb-Abb-Bb (a Db diminished seventh chord). E-G-Bb-C# can be spelled Fb-Abb-Bb-Db. G-Bb-Db-Fb can be spelled Abb-Bb-Db-Fb.   Finally, Bb-Db-Gb-Fb can be spelled Cbb-Db-Fb-Abb.
This gets pretty crazy although it's theoretically possible but who the hell wants to play
a Cbb diminished seventh chord? Not me. If you don't believe me about all this,
check it out on a keyboard.

If I made an error, please point it out.

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 29 Aug 13 - 08:20 AM

I was confused about what talking about back in 2004, Frank. I understand the concept, but just didn't get at first that was what you meant. This is because one can't skim thru explanations of music theory.

As to the A7, Artful Codger, it's not a "harmonic alternative", it is the dominant chord in the key of D minor, so when you move from C to A7, you've got a key change. The trick here is that the D minor chord is also the ii chord, and an extension of the Dominant harmony, in the key C(Dm: D F A, G9: G B D F A), so depending on where you go next from the Dm, you can be in either the key of D minor or the key of C.

Subject: RE: Diminished chord notation question
From: Stringsinger
Date: 28 Aug 13 - 07:01 PM

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Subject: RE: Diminished chord notation question
From: M.Ted - PM
Date: 24 Aug 04 - 06:12 PM

Oh-- I missed those posts from Frank and MCP--

So Frank-What does this mean?>

OK. Here's a concrete example. Let's take C#o7 (C# diminished seventh).
C# is the third note of the scale of A. A is the generator.

A7b9 is spelled A-C#-E-G-Bb (R (for root) 3-5-b7-b9. Root=Generator.
The top four notes of this chord are C#-E-G-Bb. This spells the C#o7 chord.
(C# diminished seventh).

The third of this A7b9 becomes the root of the diminished seventh.
The C# now being the root, the chord is spelled R-b3-b5-bb7. There is no 6th
in a diminished seventh chord.

So, the C#o7 (diminished seventh) substitutes for the A7b9.

Ultimately, C#o7 substitutes for an A7 chord.

This is the classic use of the diminished seventh chord.

You'll have to look at this a while to get it. Try writing it out in another key.
For example, G7b9 becomes Bo7 which subs for G7.

Subject: RE: Diminished chord notation question
From: GUEST,Stim
Date: 28 Aug 13 - 01:16 AM

You had to ask that!!!! Damn you!!!;-)

Given that you've made it this far in life without knowing the answer to that question--you may ask yourself two things--1)"why haven't I gleaned the answer to this from years of casual conversation with my musical friends?" and 2) "Am I willing to make the effort it takes to make sense out of what is basically the music theory version of the blind men and the elephant?"

But seriously, this question has a big, technical answer, and it's not something that can be spelled out in a half a paragraph by someone who really should be putting away laundry, or dishes, or maybe driving over to the Home Depot to get some hardware to repair something he's been meaning to fix since last February.

Anyway, the answer, which is pretty much the central idea underlying music theory from the before Bach to slightly before Stravinsky really deserves a thread of it's own. Give Jack Campin or Stringsinger, or a few of the others who like to expound on this sort of thing a
crack at it...or you can go to Julliard and see what they know....either way.

Subject: RE: Diminished chord notation question
From: Artful Codger
Date: 27 Aug 13 - 08:23 AM

Ahem, the progression C/A7/Dm/G7 does NOT follow the circle of fourths going from C to A, though the circle is followed from then on.

Note also that A(7) is not a native chord to C major; even in the temporary tonality of Dm, it's a harmonic alternate of the natural Am(7). While these progressions sound perfectly fine, what's happening harmonically in the move from C to C#dim/A7 isn't adequately explained. Yes, it works, but WHY?

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 25 Aug 04 - 11:36 AM

This phrase:
"When he talks about a chord being mislabelled and how it officially works--he really means finding a label for the chord that makes what is happening in terms of music theory"--

Should read like this:

"When he talks about a chord being mislabelled and how it officially works--he really means finding a label for the chord that makes sense of what is happening in terms of music theory"--

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 25 Aug 04 - 11:33 AM

For those whose brains hurt---sorry for the confusion--

Here is a bit of clarification for Frank's point--

When he talks about a chord being mislabelled and how it officially works--he really means finding a label for the chord that makes what is happening in terms of music theory--

He uses the chord C#° as an example--

To make it easier--here is the kind of chord progression that it would occur in: C/ C#°/Dm/G7--

So the question is--why does that C#° chord make sense in a chord progression that otherwise seems to be in the key of C?

Before we get to Frank's answer, remember that we've talked about the fact that the Dominant Seventh Chord(G7, A7, D7, etc) contains a diminished triad--

G7 is G-b-d-f   and the b-d-f are a diminished triad--

So if you take a diminished triad, such as b-d-f-, and add a note that is a major third (two major scale steps) below the root of the diminished chord (which, in this case, is b) you get G-b-d-f--which is G7--

Frank points out that generally, in chord notation, the diminished chord is usually a diminished 7th--

Frank's example is a C#°, which would be C#-E-G-Bb--so when we add the major third below the root of the diminished chord, we have A- C#- E -G- Bb, which is an A7b9 chord--

Now if we substitute this chord, we end up with this progression: C /A7(b9)/ Dm /G7--which is a circle of fouths chord progression that we all understand--

(I put the b9 in parens because, as is always the case, those extra notes are flavoring, and can be left off without altering the chord progression)

This means that when you see a diminished chord, such as B° or C#° in a chord chart, you can simply turn it into a dominant seventh chord by adding the note two major scale steps below, and play the G7 or A7 instead--

Subject: RE: Diminished chord notation question
From: Grateful Ted
Date: 25 Aug 04 - 10:49 AM

errh.... I'll get my coat.

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 25 Aug 04 - 10:34 AM

This is from s&r's link--read it first, and it will help make sense out of the stuff we have written above--Music theory can really can be very straight forward, providing you start at the right place--

http://www.fact-index.com/d/di/diminished_chord.html

Diminished chord
Generally speaking, a diminished chord is a chord which has a diminished fifth in it. More specifically, it is a three-note chord consisting of a minor third and diminished fifth above the root - if built on C, a diminished chord would have a C, an E flat and a G flat. The interval between the upper two notes is also a minor third - thus, the chord consists of two minor thirds stacked on top of one another. It resembles a minor triad with a lowered (or diminished) fifth.

In the common practice period, the diminshed chord is considered dissonant, or unstable. It lacks tonal center or drive because the diminished fifth symmetrically divides the octave. Adding a further minor third on top of the chord (if built on C, this results in a chord consisting of C, E flat, G flat and B double-flat, the last of which may be enharmonically respelled as A) makes a diminished seventh chord (so called because C to B double-flat is the interval of a diminished seventh). This chord is ambiguous as to root because a diminished seventh chord built from any note of it produces that same chord. This, combined with the fact that any of its notes may be eharmonically changed, makes it a useful pivot chord for modulation.

A diminished chord occurs in a major scale only on the seventh scale degree; in the key of C, this is BDF. This also occurs in the seventh chord built on the fifth note (that is, the dominant seventh); in C, this is GBDF. The diminished chord on the leading tone can thus function as a dominant seventh and resolve to the tonic chord. The diminished fifth is part of the strong sense of resolution possible in the progression from the dominant seventh to the tonic.

In a twelve tone equal tempered tuning, a diminished chord has 3 semitones between the third and fifth, 3 between the root and third, and 6 between the root and fifth. It is represented by the integer notation 0,3,6.

Subject: RE: Diminished chord notation question
From: s&r
Date: 25 Aug 04 - 06:32 AM

I find this a straightforward explanation of diminished chords.

Stu

Subject: RE: Diminished chord notation question
From: The Fooles Troupe
Date: 25 Aug 04 - 05:55 AM

I did 5th Grade Music Theory, and my head still hurts - we certainly didn't go into this sort of depth... but keep it up, it's certainly educational!

Robin

Subject: RE: Diminished chord notation question
From: Grateful Ted
Date: 25 Aug 04 - 03:55 AM

My brain hurts!

Subject: RE: Diminished chord notation question
From: Cluin
Date: 25 Aug 04 - 02:33 AM

The basic diminished triad is easier to play on other instruments (like the piano) than it is on the guitar, where we commonly opt for the 4 note diminished 7th chord (unless we play jazz). That way we don't have deaden as many strings.

It makes a nice sliding chord too... move it up three frets and the same chord (just a different inversion of it) is repeated. And any note of the chord can be considered the root note,
i.e. Cdim7 = Ebdim7 = Gbdim7 = Adim7
   xx1212

This means there are only really three diminished chords, guitar-centrically speaking. But like all chords they can be played in several positions for different sounds and effects.

Guitarists simply call it a Xdim chord, eg. Edim or Eo. If one of your fancy-shmancy jazz guitarists want to refer to the 3 note diminished chord, it's called a diminished 5th chord, eg. E dim5 or E-5

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 25 Aug 04 - 12:38 AM

OK--it just wasn't clear from the way he had worded it--at any rate, it always seemed to me that the inverse was the case, that the altered dominant 9th chord could be substituted for the appropriate diminished 7th chord--or actually is just an extension of that chord--

Subject: RE: Diminished chord notation question
From: GUEST,MCP
Date: 24 Aug 04 - 06:51 PM

M.Ted

Frank's post relates to the fact that the upper 4 notes of a dominant 7th with a flat 9th make up a diminished 7th chord chord:

C7b9 = [C E G Bb Db]

Take the top 4 notes: [E G Bb Db] and you have an Edim7 and this can substitute for the altered dominant 9th chord with the root omitted (or as Frank puts it Edim7 substitutes for the C7b9 chord, whose root C is a major 3rd lower than the root E of Edim7).

Mick

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 24 Aug 04 - 06:27 PM

GUEST posted again, and I missed it, cause I was writing my post--the way to keep things straight is to think about direction of the movement through the chord changes----the half diminished chords mostly are used as a substitute for the II minor chord leading into the dominant 7th--such as Am7-5 D7/ G G

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 24 Aug 04 - 06:12 PM

Oh-- I missed those posts from Frank and MCP--

So Frank-What does this mean ?

"The root of the diminished chord is taken from the "generator" or the dominant seventh flat nine chord which is a major third below that root"--

When you are in the key of C and scrunch up a half step, you go to a C#diminished--yes, you are actually moving though the circle of fifths to the A dominant call it what you want (and into the key of D)--but you wouldn't want to name it that way on a chart is that you want the player to know that you are moving up from the tonic by half steps and not down by a minor third (which is what you will get if you punch an A7b9 or onto the chart--

On a score, which has all the part written out, the chord naming(which is, because all the parts are written out, academic) would follow the movement through the circle of keys, but on a chart, the chord names are there to give a sense of how the bass line is supposed to move--

Subject: RE: Diminished chord notation question
From: GUEST
Date: 24 Aug 04 - 05:47 PM

"Okay, I think I got it now..."

Looks like my software is calling C, Eb, Gb - the basic diminished triad - "Cdim." "C diminished."

1, b3, b5, bb7(6) - e.g. C, Eb, Gb, A - my software is calling "C with the little circle symbol" .... If I follow the discussion, this is what is known as a "diminished 7th" chord - in this instance, "C diminished 7th."

1, b3, b5, b7 - e.g. C, Eb, Gb, Bb - My software is calling Cm7b5. "C minor7th flat5th." This is the one you guys are calling a "half-diminished" chord. "C circle with a line thru it" or "C circle with a line thru it and a '7' following."

So, I'm happy. Thanks people. My theory lesson for the day. Now if I can only remember it.

I am familiar with basic diminished chord theory. The way I remember it is each interval is composed of a minor 3rd...minor 3rds stacked on top of each other. I think I'm going to have to memorize the "1, b3, b5" in order to keep straight in my head the difference between a true "diminished 7th" chord (the 3rd, 5th and "dominant7" or "b7" intervals are "diminished" by a half tone) ...and the "half diminished" chord (the 3rd, 5th, but NOT the "dominant7" or "b7" interval is diminished by a half tone) ....

Thanks again.

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 24 Aug 04 - 05:27 PM

God help GUEST! Here is the answer to your question--Yes.

As is more or less pointed out above, the dominant chord (V7--G7 in C, etc) is really a diminished chord-- B D F --based on the leading tone,( which is a half step below the fundamental) that holds on to the fifth step of the tonic chord.

I mention this only because it allows me to introduce my "slinky" chord theory--which is that you think of the scale as a slinky which you either scrunch up or stretch to make chords---Start with the tonic, C E G--stretch it down a half step with the top end anchored down and you get the
dominant--B D F   G--keep the top anchored scrunch it up, and you get C#dim--C# E G--slide the whole thing up, and you get Dm--D F A--keep the bottom fixed and scrunch down for a Cdim--

Subject: RE: Diminished chord notation question
From: GUEST,MCP
Date: 24 Aug 04 - 05:06 PM

Sky-Coyote - Sorry about that (bb5 in my post should of course have been bb7) - thanks for the correction!

I realise looking that I also made another mistake when I said that sharpening any note of a diminished 7th chord created a dominant 7th chord - that should have been flattening any note of a diminished 7th chord creates a dominant 7th chord. Thus if we look at Cdim7:

Cdim7 = C Eb Gb A

Flattening the notes one at a time (and rewriting the notes and reordering to make the chord clear) gives:

  1.  Cb Eb Gb A = B D# F# A                      = B7
  2.  C Ebb Gb A = C D Gb A = C D F# A = D F# A C = D7
  3.  C Eb Gbb A = C Eb F A = F A C Eb            = F7
  4.  C Eb Gb Ab = Ab C Eb Gb                     = Ab7
  

Mick

Subject: RE: Diminished chord notation question
From: GUEST,Frank
Date: 24 Aug 04 - 05:02 PM

Many times a diminished seventh chord is mislabled. (o7). Here's how it officially works. The root of the diminished chord is taken from the "generator" or the dominant seventh flat nine chord which is a major third below that root. Put simply, if you have a C#o7 chord, the generator is
A and the chord is built on A7b9. So the diminished seventh chord substitutes for the dominant seventh flat nine. Root of diminished seventh has generator a major third below.

When you see a designation for a diminished chord with the "o" it means a diminished seventh always. This is a carryover from pop music of the 20's through the 50's and used sparingly later. The three note diminished chord is generally not used in lead sheets.

Frank

Subject: RE: Diminished chord notation question
From: Sky-Coyote
Date: 24 Aug 04 - 04:22 PM

Hello Guest,MCP
Thanks for the continuation on Diminished Chord Theory. Just a quick edit that a diminished 7th chord (dim7 or o7) is made up of[1 b3 b5 6 (bb7)] of the scale as I saw a typo in the last message and just thought that I would make sure there is no question lurking in anyone's mind.
Thank You, Sky-Coyote the Jazzin' Hobo.

Subject: RE: Diminished chord notation question
From: GUEST,MCP
Date: 24 Aug 04 - 04:07 PM

To amplify on the diminished type chords:

The diminished triad is just the [1, b3, b5] chord, so called because the interval 1-b5 is a diminished interval. This is the one written as Cdim for example.

The chord you'll probably come across most often is the diminished 7th chord (dim7) [1 b3 b5 6(or bb5 as Sky-Coyote noted above)]. This chord can be created by taking a dominant 7th chord [1 3 5 b7] (like C7) and flattening every note except the root, thus dominant 7th=[1 3 5 b7], flatten every note except the root gives [1 b3 b5 bb7]=[1 b3 b5 6]=diminished 7th chord, often written as Cdim7 or Co7 or just Co and is the chord most often meant in standard chord sequences when Cdim is written. (The chord is useful because sharpening any one note of the chord produces a dominant 7th chord and thus depending on which note you sharpen, lets you go off in several directions).

The half-diminished chord is a minor 7th chord with a flattened 5th: [1 b3 b5 b7] and may be written as Cm7b5, Cm7-5 or again as Sky-Cotote noted as Cø7 or Cø.

Mick

Subject: RE: Diminished chord notation question
From: Sky-Coyote
Date: 24 Aug 04 - 02:43 PM

Hello Guest,
Try thinking about a diminshed chord as 1-b3-b5-bb7 (bb7 is in reality the 6) in it's construction and your software is most likley making a distinction between what is really a -b5 ("-" means minor) chord with no b7 or in most jazz charts it would be a half diminished chord which is marked as o with a slash through the circle (and almost always has a b7) versus a true 4 tone diminished chord with the bb7 (Co). I find in my playing and notation that while I do occasionally play three tone "diminshed" chords I find it usefull to be able to distinguish what the chords are in a pratical sense. Their are many schools of thought on notation and I am sure all are useful and so is your software because it gives you a clear choice on note selection. Diminished four tone chords and half dimished chords are a wonderful thing and the Inversions sound great when building tension in a song and/or moving into another position.
Have Fun, Sky-Coyote the Jazzin' Hobo

Subject: RE: Diminished chord notation question
From: M.Ted
Date: 24 Aug 04 - 02:34 PM

Curious to know what names they use for the both of them--

Subject: RE: Diminished chord notation question
From: GUEST,MMario
Date: 24 Aug 04 - 02:16 PM

it looks to me that they are using the two means to distinguish between the triad and the 4 note chord.

Subject: Diminished chord notation question
From: GUEST
Date: 24 Aug 04 - 01:58 PM

I have a chord finder freeware program that makes a distinction between a diminished chord and the same chord notated with the little "o" symbol. For example:

It lists the notes for Cdim as C, Eb, Gb. It lists the notes for C(with the little "o" symbol) as C, Eb, Gb, A.

I thought "dim" and "o" following a chord meant the same thing. Perhaps not?

Thanks in advance.