What's the difference between a diminished chord and a diminished 7th chord?

[edh]

Yes, that's a common way of spelling it. rpguitar and I were just using abbreviations for "minor" (m) and "diminished" (d) for the respective intervals. This is more correct theoretically, and can sometimes help avoid confusion.

ahh...yes, I see it now. At first read thru I was reading d and b. My mind converted d to b. My mistake.

[chrisb587]

I know the theory thanks - but that's my point isn't it - there is a difference between a dim and a dim7 but jazzers may call them both dim ? This has been my experience aswell at home ... as possibly it's much easier to play a dim7 quickly on the guitar ?

Makes it difficult for people with less experience to learn ... don't you think ?

For instance a G7 with an added 6th note wouldn't be called a G7 would it ?

Crazy

[JonR]

I know the theory thanks - but that's my point isn't it - there is a difference between a dim and a dim7 but jazzers may call them both dim ?

Yes, because basically they never play a dim triad! They'll always add a 7th - either a minor 7th (to get a half-dim or m7b5) or a diminished 7th to get a dim7.
So they often call (or write) the latter as "dim" for short, or the little circle, without the "7"; the dim7 extension is assumed. (Unless it clearly specifies m7b5, or the half-dim symbol.)
It's similar to the way we use the word "sus" to mean "sus4", because you almost never see a "sus2" in jazz. (Sus2s would tend to be regarded as an inverted sus4.)

This has been my experience aswell at home ... as possibly it's much easier to play a dim7 quickly on the guitar ?

There is that too. Dim triads are awkward, or don't sound too good. They always benefit - both soundwise and technically - from the addition of one or other 7th. (Although of course you need to know which.)

Makes it difficult for people with less experience to learn ... don't you think ?

Yes. It often seems like a jazz conspiracy, to make the symbols as cryptic as possible to maintain some kind of "secret" . But really it's just an evolved system of shorthand, where experienced players know what they mean, and only need to give hints to each other.
It's similar to the way jazz musicians play too: never overstating, communicating in nods and winks.

For instance a G7 with an added 6th note wouldn't be called a G7 would it ?
Crazy

It doesn't seem crazy to me to change the name of a chord when you change the notes!

G7 with a 6th added would be called "G13" - which seems logical enough to me: either thinking "6+7 = 13", or looking at the stacking process: 1-3-5-7-9-11-13. The 13th note is the same note as the 6th, but the figure "13" implies the inclusion of the 7th (and maybe 9 and 11), because it's just the last note added to the stack. Same as "9" = 1-3-5-7-9, and "11" means 1-3-5-7-9-11.
(However, complications arise due to exceptions made for practical aural reasons: eg the omission of 11ths from "13" chords.)

[chrisb587]

Thanks for response - I agree with you but it's a contradiction isn't it - on the one hand a chord has an extra note but you call both chords dim - whereas a G7 with an extra note in it will be called something else - now that's crazy

Believe me for someone learning to understand this - it's important to know the difference in the chord names before you start calling them the same based on knowledge ..

See I don't believe it's strictly G13 either - G7/6 possibly; a G13 needs a ninth and an eleventh in the theory book I own (Understanding Harmony - Leon White) , but in practise we play a chord with neither in and call it a G13 - that's fine but that's application - not the theory isn't it ?

The point I'm trying to make (badly maybe) is that there must be readers here who are building up their knowledge reading this (and who would never dare to add a comment) not realising there are assumptions and shorthands going on ...

btw Leon White doesn't acknowldedge the sus2 at all - like you sus to him means sus4

[ColinO]

The point I'm trying to make (badly maybe) is that there must be readers here who are building up their knowledge reading this (and who would never dare to add a comment) not realising there are assumptions and shorthands going on ...

That would be unfortunate. But the best way to learn how to speak a language is to be immersed in it and dive right in and try and speak it yourself. You will make mistakes, no doubt, but you will also learn. You won't learn the shorthand if no-one ever uses it in front of you.

[JonR]

Thanks for response - I agree with you but it's a contradiction isn't it - on the one hand a chord has an extra note but you call both chords dim - whereas a G7 with an extra note in it will be called something else - now that's crazy

Not really, when you see the reason for the names.
Dim7s get called "dim" (often, not always), because no other chord in common use gets that name (dim triads being vanishingly rare).
G7 and G13 are both common, so definitely need different names.
And if in any doubt, then any jazz player will specify "dim7" when necessary.

Believe me for someone learning to understand this - it's important to know the difference in the chord names before you start calling them the same based on knowledge ..

Right. And that's what we're explaining here.
If you're studying theory from scratch, you learn about dim triads, dim7s and half-dims first (I mean along with other chord types and their structures). You don't dive into jazz charts and expect to understand all their shorthand: the logic is often concealed behind abbreviations, which you pick up the more you study jazz.
IOW, theory in books is one thing. Chord symbols are something else: a shorthand designed for reading (by those familiar with the language) not for illustrating theoretical concepts perfectly.

See I don't believe it's strictly G13 either - G7/6 in the books I own; a G13 needs a ninth in the theory book I own, but in practise we play a chord with no ninth in it and call it a G13 - that's fine but that's application - not the theory isn't it ?

Well, yes. The 9th in a G13 is optional.
I've seen the symbol "G7/6" occasionally (specifying the exclusion of 9 and 11), but never in jazz charts or books. That's because the musicans those charts and books are aimed at know that a "13" chord omits the 11th anyway, and it makes little difference whether the 9 is in or not (although they will also know the difference the 9th makes, and if some contexts might make it important). So "G7/6" is redundant.

You're right the theory may not tell you that, although really it should (IMO). Theory is based on practice, after all (not vice versa), and it's a little silly to state - as some sources do - that a G13 chord has every note in it: G B D F A C E. The C would never be included. All the other notes could be; but as I say, the A doesn't make a lot of difference (in or out). Neither does the D.

This is, admittedly, another level of the theory: the reasons why (and when) certain potential chord tones might be omitted. You could call it "application", but seeing as these practices are common enough to be standard, I'd say they were part of theory. "Jazz theory" at least.
I'd agree you can't possibly know the ins and outs by seeing a "G13" symbol, and trying to rationalize from a basic knowledge of chord forms.

The point I'm trying to make (badly maybe) is that there must be readers here who are building up their knowledge reading this (and who would never dare to add a comment) not realising there are assumptions and shorthands going on ...

OK, fair point. But one should never try to learn theory by reading threads on jazz theory boards!
(At the same time, knowledgeable folk shouldn't overestimate the knowledge of those asking questions.)

People on jazz sites do tend to know their stuff (a lot better than the average person on rock sites), but they tend to know it so well that they forget that for many people things need spelling out.

[BigDaddyLoveHandles]

Thanks for response - I agree with you but it's a contradiction isn't it - on the one hand a chord has an extra note but you call both chords dim - whereas a G7 with an extra note in it will be called something else - now that's crazy

The language is somewhat informal.

[Patrick2]

Great points and interplay between JonR and Chrisb587. This has been a very informative thread for me . . for two reasons. Firstly, I learned some stuff from those who contributed and secondly . . being away from studying jazz theory for such a long time . . . it caused me to further research dim vs dim7 chords. Ceck out what I found . . .

Diminished seventh chord - Wikipedia, the free encyclopedia

[chrisb587]

Thanks for all the advice - Jon - I'm only chirping up because I want to learn ..

[edh]

Thanks for all the advice - Jon - I'm only chirping up because I want to learn ..

As you should. I'm always chirping up and have recieved helpful information.

The guys here are very cool.

[docbop]

Greg Fishman has some good info on his site.

Article 3

[JonR]

Thanks for all the advice - Jon - I'm only chirping up because I want to learn ..

No problem.
I like practising my explanations too! Always good to fill the holes...

[BigDaddyLoveHandles]

Greg Fishman has some good info on his site.

Article 3

I love his example #2, playable only on the piano: Bdim7 (B D F Ab) in LH and A#dim7 (A# C# E G) in RH. Jelly.

[Lafayette]

Hello everyone! I'm new here. I am not into jazz that much, although I like Benny Goodman and Bing Crosby and others from that era. What I'm into is learning music and you people know a whole lot and that is why I'm here.

What led me here is my confusion concerning diminished and diminished seventh chords. I have seen on the internet and in a Mel Bey guitar chord book that the diminished chords have a seventh note added to them. I can understand and appreciate the logic of calling dim7s diminished sevenths if they have a seventh added to them, but not when there is no seventh. To me and others like me trying to learn music this becomes chaotic.

I have thought of another question. What if I was to write a song giving guitar chords (without diagrams) and I included a diminished chord with just the triads, but without the seventh. How would the guitarist know that he/she was to omit the seventh when most of the music literature includes the sevenths?

Lafayette

[Rob MacKillop]

I think the original question has been answered: yes, in jazz terms they are often the same.

Moving on to usage, this might help some...

1. The dim7 is a great passing chord between chords a tone apart in any key. For instance (I can't find the sharp sign on my iMac keyboard...)

C Major = Cmaj7 Dm7 Em7 Fmaj7 G7 Am7 Bdim

becomes

Cmaj7 (Csharp dim7) Dm7 (Dsharp or Eb dim7) Em7 Fmaj7 (Fsharp dim7) G7 (Gsharp dim7) Am

In other words, it's a great chord to place on the chromatic notes between chords

2. In the V - I progression, G7 to C, we can make the V chord into G7b9 - which includes all four notes of F dim7 - F B D Ab. So we can play a dim7 chord or run starting from the 7th or b9, or 3rd or 5th of a V7 chord.

There are other uses, of course, but these are the most common.

[nikolozj]

Also very common thing for diminished chord is that as long as they are built with thirds, that also means that the chord shape will be same on each third on fingerboard if you move it around.

There are actually only three dims:

Cdim / F#dim / Ebdim / Adim
C#dim / Edim / Gdim / Bbdim
Ddim / Fdim / Abdim / Bdim

So, to get back to thread question, what did we found out finally about terms?

They call full diminished chord "diminished 7" and they call half diminished chord "diminished chord"?

[JonR]

Hello everyone! I'm new here. I am not into jazz that much, although I like Benny Goodman and Bing Crosby and others from that era. What I'm into is learning music and you people know a whole lot and that is why I'm here.

What led me here is my confusion concerning diminished and diminished seventh chords. I have seen on the internet and in a Mel Bey guitar chord book that the diminished chords have a seventh note added to them. I can understand and appreciate the logic of calling dim7s diminished sevenths if they have a seventh added to them, but not when there is no seventh. To me and others like me trying to learn music this becomes chaotic.

I have thought of another question. What if I was to write a song giving guitar chords (without diagrams) and I included a diminished chord with just the triads, but without the seventh. How would the guitarist know that he/she was to omit the seventh when most of the music literature includes the sevenths?

Lafayette

Hopefully the guitarist would know from context which 7th to include. Eg:

"Bdim - E - Am" - implies Bm7b5, not Bdim7.
"Bdim - Cm" - implies Bdim7, not Bm7b5.

If you don't think they'll know that, then you need to specify. There could easily be other contexts where it isn't as clear, so I'd never think it was a good idea to just label a chord "dim" - unless you intend it to be dim7, which would be the usual assumption (from jazz shorthand). Or unless you really don't mind which type of 7th, and are happy to leave to the player's judgment.

Eg, "Bdim- C(maj)" could work as either Bm7b5 (diatonic vii chord) or Bdim7 (borrowed from C minor). The latter has a chromatic Ab, so you'd need to believe that that could sound equally good as A natural - and leave it to the player to put his/her own interpretation/preference on it. (At the same time, it's probably more likely to cause confusion, as a player stops to wonder what you really mean... Sure, they could avoid the issue by just playing the triad, but it still seems an unnecessary risk.)

Don't forget that just because you label a chord in full (Bm7b5, Bdim7) that doesn't mean a jazz player will necessarily include all the notes. He/she may decide to omit the 7th anyway if they think they can get better voice-leading between chords either side without it.
IOW, think about why you're putting a dim chord in your progression anyway, and which type of dim chord it would be (what's its function?); then label it clearly (depending perhaps on the experience of whoever it is you're writing for, but always better to give too much info than too little).

[Lafayette]

Thanks everyone for your knowledgeable input. It's going to take me a little while to digest it, but that is why I'm here.

Incidentally, when I mention writing a song I meant it for the general public not just for jazz musicians.

Lafayette