# Terminology for sixth and ninth chords



## GuyBarry

As I mentioned elsewhere, I've just been experimenting with writing in a jazz idiom, and I'm finding some of the chord terminology quite confusing. I'm used to the terminology for seventh chords: 

a plain "seventh chord" (e.g. C7) is a major triad plus a minor seventh
a "minor seventh chord" (e.g. Cm7) is a minor triad plus a minor seventh
a "major seventh chord" (e.g. Cmaj7) is a major triad plus a major seventh
a "diminished seventh chord" (e.g. Cdim7) is a diminshed triad plus a diminished seventh

So far, so good. But when you get to sixths and ninths the terminology can be quite counter-intuitive. For example:

a "minor sixth chord" (e.g. Cm6) is a minor triad plus a _major_ sixth
a "minor ninth chord" (e.g. Cm9) is a minor triad plus a minor seventh and a _major_ ninth

You'd expect a so-called "minor sixth" or "minor ninth" chord to include the interval of that name, but it doesn't. The "minor" part refers to the triad and the "sixth" or "ninth" part is major by convention, apparently.

To confuse things still further, a "dominant minor ninth" chord actually _does_ contain a minor ninth - it's a dominant seventh plus a minor ninth (written C7b9 or C7-9). So a "donminant minor ninth chord" isn't a type of "minor ninth chord"!

Is this terminology used in classical music as well or is it unique to jazz and popular music? I find it horribly confusing and would like to know how it originated.


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## Vasks

Don't sweat it, Guy. All of what you said is correct, but jazz/pop chord theory is totally different than Classical music traditional theory. How is it different? Well, traditional Classical music theory is rooted in chord relationships in a key. Pop/Jazz chords ignores relationships and just says play this chord regardless of how it may or may not relate to the key. How did it evolve? I'm not sure but clearly simplicity was a driving factor.


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## GuyBarry

So how would a jazz "minor sixth" chord (e.g. C-Eb-G-A) be notated in classical theory?


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## Vasks

Well, first for Classical theory, the chord has to "exist" in a specific key either as a "diatonic" chord or a standard "chromatic" chord and then assigned Roman numeral analysis. Pop chord symbols are not used; so one can't call it Cm6. You also can not use an added sixth as part of Roman numeral analysis. Added seconds, fourths and sixths were not used until the 20th Century so they fall out of the range of traditional Roman numeral labeling. Thus if you were in the key of B-flat major, the Cm6 chord would exist only as a vii half-diminished chord (A, C, E-flat, G) in first inversion (the bass note being "C"). 

So you can see jazz/pop chord analysis is way different than Classical.


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## EdwardBast

Another difference between jazz and classical theory is that classical nomenclature is based on function and jazz nomenclature is largely descriptive — which I think is a different way of saying the same thing Vasks did. For example, jazz theory doesn't distinguish between chords of the augmented 6th and dominant 7th chords — they tend to get lumped together as so-called tritone substitutions for one another.


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## GuyBarry

Thanks for the above comments. I suppose I was wondering more about the _names_ of the chords rather than the notation for them. For most of the chords that I've used up until now, the names of the chords in jazz and popular music are the same as in classical music: major, minor, augmented, diminished and the various types of seventh chord. You also get things like suspended fourths which appear to be the same. It's only when you get on to sixth and ninth chords that the terminology appears to diverge. As already pointed out, a chord like C-E-G-A could only be analysed in classical theory as the first inversion of a minor seventh chord.

I suppose each genre of music is likely to adopt terminology that's suited to that particular genre. It's just a shame from my point of view that jazz has decided to use terminology for chords that's at odds with the established terminology for intervals.


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## EdwardBast

GuyBarry said:


> Thanks for the above comments. I suppose I was wondering more about the _names_ of the chords rather than the notation for them. For most of the chords that I've used up until now, the names of the chords in jazz and popular music are the same as in classical music: major, minor, augmented, diminished and the various types of seventh chord. You also get things like suspended fourths which appear to be the same. It's only when you get on to sixth and ninth chords that the terminology appears to diverge. As already pointed out, a chord like C-E-G-A could only be analysed in classical theory as the first inversion of a minor seventh chord.
> 
> I suppose each genre of music is likely to adopt terminology that's suited to that particular genre. It's just a shame from my point of view that jazz has decided to use terminology for chords that's at odds with the established terminology for intervals.


I believe that in classical music C-E-G-A, when it is a final chord, is occasionally analyzed as a major chord with an added 6th. If memory serves, this occurs in Mahler's _Das Lied von der Erde_?

I view it not as a shame, but as more of a purely practical matter that in jazz, for example, C-E-G-A is described as a major 6th chord rather than as a first inversion minor seventh chord. It is simply more concise to write C∆6 than to write Am7/C.


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## millionrainbows

GuyBarry said:


> As I mentioned elsewhere, I've just been experimenting with writing in a jazz idiom, and I'm finding some of the chord terminology quite confusing. I'm used to the terminology for seventh chords:
> 
> a plain "seventh chord" (e.g. C7) is a major triad plus a minor seventh
> a "minor seventh chord" (e.g. Cm7) is a minor triad plus a minor seventh
> a "major seventh chord" (e.g. Cmaj7) is a major triad plus a major seventh
> a "diminished seventh chord" (e.g. Cdim7) is a diminshed triad plus a diminished seventh
> 
> So far, so good. But when you get to sixths and ninths the terminology can be quite counter-intuitive. For example:
> 
> a "minor sixth chord" (e.g. Cm6) is a minor triad plus a _major_ sixth
> a "minor ninth chord" (e.g. Cm9) is a minor triad plus a minor seventh and a _major_ ninth
> 
> You'd expect a so-called "minor sixth" or "minor ninth" chord to include the interval of that name, but it doesn't. The "minor" part refers to the triad and the "sixth" or "ninth" part is major by convention, apparently.


Drop the interval thinking. 
Firstly, designate a chord by its quality: major or minor, which refers to its third.

Secondly, designate whether it is a seventh chord or not: 
Designate it a "seventh" chord if it has a flatted seventh. Call it a "major seventh" if it has a major seventh.

Examples: 
CM7 is C-E-G-B. (C major seventh)
Cm7 is C-Eb-G-Bb. (C minor seventh)
Cm/M7 is C-Eb-G-B. C minor/major seventh)



> To confuse things still further, a "dominant minor ninth" chord actually _does_ contain a minor ninth - it's a dominant seventh plus a minor ninth (written C7b9 or C7-9). So a "donminant minor ninth chord" isn't a type of "minor ninth chord"!


Don't call it that, then: call it a C7 flat nine.
It is a "dominant " chord because it is a 7 chord, meaning flatted seventh.
After that, designate its ninth, and whether it is altered.

Example: 
C9 is a C major with a flatted 7 and a ninth: C-E-G-Bb-D. The 7th is understood. You could say C7/9 if you wanted. But not C7-9, because the dash (-) means minor.

Some like to use the dash to denote minor chords: C-7 means C minor with a flatted seventh. I don't. I prefer Cm7.



> Is this terminology used in classical music as well or is it unique to jazz and popular music? I find it horribly confusing and would like to know how it originated.


It's not confusing if you straighten your thinking out. You sound like you already know figured bass, which uses interval distances.


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## millionrainbows

GuyBarry said:


> So how would a jazz "minor sixth" chord (e.g. C-Eb-G-A) be notated in classical theory?


You need to make the distinction between a chord name (what it is called orally) and chord designation, how it is written.

A jazz "chord name" like "minor sixth" does not really apply in classical theory, since classical deals with minor/major/diminished/augmented/seventh/ninth chords and does not specify alterations or upper extensions past the ninth, to my knowledge.


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## Vasks

millionrainbows said:


> Don't call it that, then: call it a C7 flat nine.
> It is a "dominant " chord because it is a 7 chord, meaning flatted seventh.


Well it's a dominant only if it goes to an F chord. But in jazz that C7flat9 might just go to any number of non-F chords.

Which is just one reason why trying to equate jazz chord designations with traditional theory does not work. Guy was just hoping there was a direct connection.


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## GuyBarry

Vasks said:


> Which is just one reason why trying to equate jazz chord designations with traditional theory does not work. Guy was just hoping there was a direct connection.


Yes, I was and obviously there isn't! I'm getting used to it gradually, but I really wonder how a beginner would cope with all this.

There seem to be inconsistent ways of interpreting the nomenclature for seventh and sixth (or ninth) chords. "C major seventh" is interpreted as "C" + "major seventh", whereas "C minor sixth" is interpreted as "C minor" + "sixth". So in the case of seventh chords the "major/minor" refers to the added note, whereas in the case of sixth chords it refers to the third of the triad. There's no real rhyme or reason to this - it just seems to be convention.

I've tried asking about this on popular music writing forums but very few people there seem to have much knowledge of theory!


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## millionrainbows

Vasks said:


> Well it's a dominant only if it goes to an F chord. But in jazz that C7flat9 might just go to any number of non-F chords.


Read what EdwardBasks said in post #5 above, which confirms what I'm about to say: In jazz, "dominant" does not refer to function, but to color (type of seventh). Flat seven chords are referred to as "dominant 7s, altered dominants, etc." as a general classification of seventh chords.



> Which is just one reason why trying to equate jazz chord designations with traditional theory does not work. Guy was just hoping there was a direct connection.


"Dominant" is used in jazz theory as a general classification of seventh chords. It does not mean, in this case, that a C7 must resolve to an F; it only designates what kind of seventh the chord has.


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## millionrainbows

GuyBarry said:


> Yes, I was and obviously there isn't! I'm getting used to it gradually, but I really wonder how a beginner would cope with all this.
> 
> There seem to be inconsistent ways of interpreting the nomenclature for seventh and sixth (or ninth) chords. "C major seventh" is interpreted as "C" + "major seventh", whereas "C minor sixth" is interpreted as "C minor" + "sixth". So in the case of seventh chords the "major/minor" refers to the added note, whereas in the case of sixth chords it refers to the third of the triad. There's no real rhyme or reason to this - it just seems to be convention.
> 
> I've tried asking about this on popular music writing forums but very few people there seem to have much knowledge of theory!


You seem to be looking for inconsistencies. "Major" is used to denote only one type of seventh: the major seventh. This is the only exception.

Otherwise, "major" refers to the quality of the chord itself, before the seventh is added.

"C Major 7" is assumed to be a major chord with a raised seventh (major seventh). It is not necessary to say "C major/major seventh" since this sounds awkward. It IS necessary to say "C minor/major seventh" when the chord is minor and the seventh is raised, as this is an unusual chord.

These "inconsistencies" and "conventions" have been developed and accepted as the clearest way to denote chords, provided that the user possesses some small degree of familiarity with charts, and can see the logical reasons behind this way of designating chord types which possess many kinds of qualities, sevenths, upper extensions, and alterations.


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## GuyBarry

millionrainbows said:


> You seem to be looking for inconsistencies.


I'm not looking for them - they keep jumping out at me!



> "Major" is used to denote only one type of seventh: the major seventh. This is the only exception.


Not so. A "diminished seventh chord" consists of a diminished chord plus a _diminished_ seventh. Up until now I had always assumed that the "diminished" part referred to the added seventh, but now it seems it refers to the quality of the triad (i.e. minor third, diminished fifth). By your analysis it should be called a "diminished diminished seventh chord", and the name "diminished seventh chord" should be used for a half-diminished chord (diminished chord plus minor seventh). I think.



> These "inconsistencies" and "conventions" have been developed and accepted as the clearest way to denote chords, provided that the user possesses some small degree of familiarity with charts, and can see the logical reasons behind this way of designating chord types which possess many kinds of qualities, sevenths, upper extensions, and alterations.


Yes indeed, but they're by no means obvious to someone coming at it with my perspective - a mixture of classical training and self-taught analysis of popular music conventions.


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## Vasks

Well, since the thread continues I'd like to add an observation. Yes, millionrainbow, the term dominant seventh chord is used in jazz to explain its construction. But think about how odd it is that the only traditional theory term for chord relationships used is the dominant seventh. There's no discussion of a supertonic, subdominant, etc. For me, the usage of the term dominant is to explain the chord's function/hierarchy in a key and yet in this instance it's not.


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## EdwardBast

GuyBarry said:


> Not so. A "diminished seventh chord" consists of a diminished chord plus a _diminished_ seventh. Up until now I had always assumed that the "diminished" part referred to the added seventh, but now it seems it refers to the quality of the triad (i.e. minor third, diminished fifth). By your analysis it should be called a "diminished diminished seventh chord", and the name "diminished seventh chord" should be used for a half-diminished chord (diminished chord plus minor seventh). I think.


Hey Guys, (and Vasks and Millions ) The real rule governing all seventh chords is this: When the 3rd and 7th are the same, one iteration is used, as in major 7th, minor 7th, and diminished 7th. When the 3rd and 7th are different, another designation is required, as in (just plain) 7th for dominants, minor major 7th, and the strangest case of all, the half diminished 7th (diminished-minor 7th) which ends up being called a minor 6th chord. So there really is a sort of system to the madness. And 6th chords are inversions of 7th chords. Except when they aren't.

The principles at work behind the rule are concision and expediency.


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## EdwardBast

GuyBarry said:


> … when you get to sixths and ninths the terminology can be quite counter-intuitive. For example:
> 
> a "minor sixth chord" (e.g. Cm6) is a minor triad plus a _major_ sixth
> a "minor ninth chord" (e.g. Cm9) is a minor triad plus a minor seventh and a _major_ ninth


I didn't directly address your specific cases in my last post. As I wrote above, the root of a Cm6 chord isn't C, it is A, a half diminished 7th chord. In general, inversions of 7th chords are called 6th chords.

9ths follow the same rule as 7ths noted above. If the 3rds and 7ths agree, one uses one iteration of either minor or major (C∆9, Cm9) and one adds a number understood to be diatonic in relation to the root. When the thirds in dominant chords don't agree, one writes (or assumes) a plain 7. So, C9 assumes a M3, m7, and diatonic 9th. Alterations of 9ths require flats or sharps.



GuyBarry said:


> Is this terminology used in classical music as well or is it unique to jazz and popular music? I find it horribly confusing and would like to know how it originated.


I would assume it evolved to meet the needs of players for unambiguous symbols that are as concise as possible. Survival of the fittest and most concise.


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## GuyBarry

Thanks for all the comments, everyone. I think the complexity of the topic can be inferred from the Wikipedia article on the subject:

https://en.wikipedia.org/wiki/Chord...usic)#Rules_to_decode_chord_names_and_symbols

It certainly requires some study!


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## millionrainbows

GuyBarry said:


> Not so. A "diminished seventh chord" consists of a diminished chord plus a _diminished_ seventh.


The "diminished" designation refers to the quality of the chord (major, minor, diminished, or augmented).



> Up until now I had always assumed that the "diminished" part referred to the added seventh, but now it seems it refers to the quality of the triad (i.e. minor third, diminished fifth).


That is correct.



> By your analysis it should be called a "diminished diminished seventh chord", and the name "diminished seventh chord" should be used for a half-diminished chord (diminished chord plus minor seventh). I think.


Look at it this way: In jazz, "major/minor/diminished/augmented" all refer to the quality.

If it is a seventh chord (which adds a fourth note to the triad), a "7" is used, which assumes it is a flatted (dominant) chord. This is the "default" 7th.

A diminished chord is a special case: it is simply called a "dim 7."

If it is other than a flat-seven, it must be designated as a "major seventh."

C-G-D, are all "major" chords, which function as I chords. If they are minor, "Cm or C minor" are designated.

If a seventh is present, it is assumed to be a flatted "dominant" type chord: C7, G7, D7.

Or if minor, Cm7, Gm7, Dm7. (Sometimes notated as C-7, G-7, D-7).



> Yes indeed, but they're by no means obvious to someone coming at it with my perspective - a mixture of classical training and self-taught analysis of popular music conventions.


There is a consistent logic to it; you don't see not yet. This comes through reading charts and encountering different situations.


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## millionrainbows

EdwardBast said:


> ...and the strangest case of all, the half diminished 7th (diminished-minor 7th) which ends up being called a minor 6th chord.


Those are best called "Minor seven flat five" chords. (D min7b5)


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## GuyBarry

millionrainbows said:


> There is a consistent logic to it; you don't see not yet. This comes through reading charts and encountering different situations.


I've read all the charts and analysed the different combinations, and I'm afraid I don't see any consistent logic. In the case of seventh chords, the seventh may be minor, major or diminished depending on the quality of the chord. In the case of sixth and ninth chords, the sixth or ninth is always major by default, irrespective of the quality of the chord.

I think you just have to sit down and learn it, to be honest.


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## Vox Gabrieli

GuyBarry said:


> I've read all the charts and analysed the different combinations, and I'm afraid I don't see any consistent logic. In the case of seventh chords, the seventh may be minor, major or diminished depending on the quality of the chord. In the case of sixth and ninth chords, the sixth or ninth is always major by default, irrespective of the quality of the chord.
> 
> I think you just have to sit down and learn it, to be honest.


Concepts such as this are much easier to understand when you're looking at scores hands-on, be it Jazz, or Classical. Go to your local Music Theorist professor, at whatever college you may or may not be near, and ask. Sometimes Wikipedia doesn't cut it when you're trying to learn things as convoluted as this can get.


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## millionrainbows

GuyBarry said:


> I've read all the charts and analysed the different combinations, and I'm afraid I don't see any consistent logic. In the case of seventh chords…


…meaning "dominant seven" chords...



> ...the seventh may be minor, major or diminished depending on the quality of the chord.


No, that's inconsistent. Remember, "seventh" chords, such as C7, means a flat seven, because it is a dominant seventh chord.

"Major 7" chords are designated "major 7" because they are not dominant; they have a major 7th and function as I chords.

"Diminished" chords are called "diminished," whether they are 7th or not. "Diminished" refers to the fifth, not the seventh.



> In the case of sixth and ninth chords, the sixth or ninth is always major by default, irrespective of the quality of the chord.


A sixth chord (such as C6) is major unless it is designated minor.
A ninth chord is C9, meaning C major with an added ninth. If it is a minor chord, it is called "Cm" or "Cm9" and the minor refers to the chord quality, not the type of ninth.
If it is Cm(b9), C(b9), or C(#9), the #9 or b9 refers to the type of ninth. It's best to use parenthesis to avoid confusion.


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## EdwardBast

millionrainbows said:


> "Major 7" chords are designated "major 7" because they are not dominant; they have a major 7th and function as I chords.
> 
> "Diminished" chords are called "diminished," whether they are 7th or not. "Diminished" refers to the fifth, not the seventh.


The diminished in C°7 indicates _both_ the 5th and the 7th, just as the major in CM7 indicates both the 3rd and 7th, and the minor in Cm7 indicates both the third and the 7th.



millionrainbows said:


> A ninth chord is C9, meaning C major with an added ninth.


No, C9 indicates a C7 chord plus a 9th.


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## GuyBarry

I'm in danger of just repeating myself in this thread, but I'll say it again slightly differently:

"Cmaj7" = "C" + "maj7"
"Cm6" = "Cm" + "6"

In the first one, you have to take the "maj" with the "7". In the second, you have to take the "m" with the "C". I regard that as an inconsistency. However, I'm happy to live with it.


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## millionrainbows

GuyBarry said:


> I'm in danger of just repeating myself in this thread, but I'll say it again slightly differently:
> 
> "Cmaj7" = "C" + "maj7"


That's correct; it doesn't contradict anything I've said.



> "Cm6" = "Cm" + "6"


"Cm6" = Cminor + "6" That's correct.



> In the first one, you have to take the "maj" with the "7".


True; that's because it is designating an exceptional seventh, not the old dominant flat-seven.



> In the second, you have to take the "m" with the "C". I regard that as an inconsistency. However, I'm happy to live with it.


No; remember, the flat-seven is the default seventh, designated as "7" with no need to qualify it as a minor seventh.

In "Cm6," there is no seventh. The "minor" therefore refers to the quality of the C chord, not a seventh or sixth.


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## millionrainbows

EdwardBast said:


> The diminished in C°7 indicates _both_ the 5th and the 7th, just as the major in CM7 indicates both the 3rd and 7th, and the minor in Cm7 indicates both the third and the 7th.


No; diminished refers to the fifth, as in the dim chord B-D-F, with no seventh. It is a primary triad, just as major/minor/augmented are. If you add a seventh, you must designate it as "diminished seventh," as in B-D-F-Ab.



> ...just as the major in CM7 indicates both the 3rd and 7th…


No; in "CM7", the "major" refers only to the seventh, since it is not the "default" flat-seven.



> ...and the minor in Cm7 indicates both the third and the 7th.


No, the "7" in "Cm7" refers only to the quality of the chord. The seventh needs no designation, since it is the default flat-seven, as all 7 chords are.



millionrainbows said:


> A ninth chord is C9, meaning *C* *major* with an added ninth. If it is a *minor* chord, it is called "Cm" or "Cm9" and the minor refers to the chord quality, not the type of ninth.





> No, C9 indicates a C7 chord plus a 9th.


The seventh is assumed, so I do not need to say it.

The full context of my statement was to clarify the difference between "chord quality" and the upper extensions, such as seventh or ninth. Emphasis was added for clarity in seeing this.

Remember, the seventh, in a chord with upper extensions such as 9, 11, and 13, is assumed, so there is no need to designate it as "C7/9".


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## GuyBarry

millionrainbows said:


> No; remember, the flat-seven is the default seventh, designated as "7" with no need to qualify it as a minor seventh.
> 
> In "Cm6," there is no seventh. The "minor" therefore refers to the quality of the C chord, not a seventh or sixth.


And that's the inconsistency that I was pointing out. With seventh chords, the "maj" or "m" or whatever it is refers to the added seventh note. With sixth (and ninth) chords, it refers to the chord quality.

We're in agreement about the facts, but I see it as an inconsistency and you apparently don't. I can't see any _prima facie_ reason why the notation for sixth and ninth chords should work differently from that for seventh chords, beyond simple convenience. I learned that "Cmaj7" means "C" + "maj7" a long time ago, so I initially assumed that "Cm6" must mean "C" + "m6". I now know that it doesn't, but there's nothing in the notation itself to suggest that. You just have to learn it.


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## millionrainbows

GuyBarry said:


> And that's the inconsistency that I was pointing out. With seventh chords, the "maj" or "m" or whatever it is refers to the added seventh note. With sixth (and ninth) chords, it refers to the chord quality.


I think what you are failing to grasp, in jazz theory, is that chords are, indeed, categorized by function: as major (I), minor (usually ii), dominant (7), and altered dominant (seems like somebody said they weren't earlier).

In jazz, if a chord is of the dominant type, meaning a flatted seventh, it is referred to as a "7" chord. If the seventh is other than flatted, it must be specified, as with M7.

All "7" chords in jazz are dominant types, so they are assumed to be major in quality. If not, they are specified as minor, with either a dash (C-7), or a small "m" (Cm, Cm7, Cm7b5).



> We're in agreement about the facts, but I see it as an inconsistency and you apparently don't. I can't see any _prima facie_ reason why the notation for sixth and ninth chords should work differently from that for seventh chords, beyond simple convenience.


The quandary is answered by determining the function of the chord. If it's a sixth or ninth chord, simply call it that: C6, Cm6, C6/9, C7/6, Cm6, all of which contain the note "A" as the sixth.



> I learned that "Cmaj7" means "C" + "maj7" a long time ago, so I initially assumed that "Cm6" must mean "C" + "m6".
> I now know that it doesn't, but there's nothing in the notation itself to suggest that. You just have to learn it.


It seems self-explanatory if you keep function in mind. By your logic, "Cmin7" would mean "C (major) + min7," just as "Cmaj7" would mean "C (major) + maj7." That seems equally inconsistent.

With "C7" understood as a dominant chord, which takes care of both the quality (C major) and the type of seventh (dominant=b7), then the problem is solved.


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## GuyBarry

millionrainbows said:


> I think what you are failing to grasp, in jazz theory, is that chords are, indeed, categorized by function: as major (I), minor (usually ii), dominant (7), and altered dominant (seems like somebody said they weren't earlier).
> 
> In jazz, if a chord is of the dominant type, meaning a flatted seventh, it is referred to as a "7" chord. If the seventh is other than flatted, it must be specified, as with M7.
> 
> All "7" chords in jazz are dominant types, so they are assumed to be major in quality. If not, they are specified as minor, with either a dash (C-7), or a small "m" (Cm, Cm7, Cm7b5).


Yes, that's what I've always understood.



> The quandary is answered by determining the function of the chord. If it's a sixth or ninth chord, simply call it that: C6, Cm6, C6/9, C7/6, Cm6, all of which contain the note "A" as the sixth.


Indeed, as has been discussed at length.



> It seems self-explanatory if you keep function in mind.


It seems self-explanatory _if you already know it_. It's not remotely self-explanatory if you're just trying to learn it.



> By your logic, "Cmin7" would mean "C (major) + min7," just as "Cmaj7" would mean "C (major) + maj7." That seems equally inconsistent.


My understanding is that sevenths are minor by default, so "C7" = C + min7. However, if the chord quality is explicitly specified, then the type of seventh can change. "Cm7" or "Cmin7" = Cmin + min7, but "Cmaj7" = Cmaj + maj7 (not Cmaj + min7), and "Cdim7" = Cdim + dim7 (not Cdim + min7).

This principle does NOT apply to sixth and ninth chords. The sixth or ninth is always presumed to be major, regardless of the chord quality. That's the inconsistency I was pointing out.


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## millionrainbows

GuyBarry said:


> My understanding is that sevenths are minor by default, so "C7" = C + min7.


In classical theory, there is no "major seventh" chord. It's a leading tone. You must be speaking on behalf of the classical academic approach.



> However, if the chord quality is explicitly specified, then the type of seventh can change.


Not in classical, to my knowledge. There is only one kind of seventh, flatted. For example, in the key of C the flatted seventh can be "F" in a G dominant.

There is no "I7" chord, such as "CMajor7," because those type chords do not exist, and have no function.



> "Cm7" or "Cmin7" = Cmin + min7…


Yes, that could happen in the key of Bb major, where Cm7 is the ii chord.



> ...but "Cmaj7" = Cmaj + maj7 (not Cmaj + min7)…


But in classical, there is no "Cmaj7" chord.



> ...and "Cdim7" = Cdim + dim7 (not Cdim + min7).


No, that's incorrect, even in classical terms. There is a chord, Bdim, which functions as vii, and is a triad: B-D-F.

If it is a seventh chord, "7" is added to specify the seventh. The "dim" _already_ means a flatted (diminished) fifth.



> This principle does NOT apply to sixth and ninth chords. The sixth or ninth is always presumed to be major, regardless of the chord quality. That's the inconsistency I was pointing out.


I have heard of seventh and ninth chords in classical, but not "sixth" chords.


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## Larkenfield

Vasks said:


> ... Pop/Jazz chords ignores relationships and just says play this chord regardless of how it may or may not relate to the key...


As a former life-long jazz musician, I haven't found this to be exactly true that there's a lack of chordal relationships in jazz harmony, though some compositions will not necessarily modulate logically from one chord to another, but will jump from one chord to another in some type of a seemingly random but still repeated pattern.

What I've found that helps in the study of chords and chord notation is to isolate those tones that make for the altered chord. In the matter of a C7-9, it's still a major chord with a flat 9 and its essence can be heard using the scale of C, Db, E, F, G, A, and Bb. The key matter is to determine the scale upon which any chord is built. In the matter of a Cm7-9, its scale would consist of C, Db, Eb, F, G, A and Bb. Also note the melody over the chord, because it will help determine the exact scale the altered chord is based on.

I also highly recommend the great jazz vibe player Gary Burton's teachings on improvising and jazz harmony in which he clearly explains the details of what I've tried to share and the importance of determining the scale that any altered chord consists of:


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## Phil loves classical

GuyBarry said:


> Yes, that's what I've always understood.
> 
> Indeed, as has been discussed at length.
> 
> It seems self-explanatory _if you already know it_. It's not remotely self-explanatory if you're just trying to learn it.
> 
> My understanding is that sevenths are minor by default, so "C7" = C + min7. However, if the chord quality is explicitly specified, then the type of seventh can change. "Cm7" or "Cmin7" = Cmin + min7, but "Cmaj7" = Cmaj + maj7 (not Cmaj + min7), and "Cdim7" = Cdim + dim7 (not Cdim + min7).
> 
> This principle does NOT apply to sixth and ninth chords. The sixth or ninth is always presumed to be major, regardless of the chord quality. That's the inconsistency I was pointing out.


Yes, I see the inconsistency. The minor sixth was "mutated" from the major sixth chord, and kept the major 6 interval, not relating to the minor key notes. It came from the use of harmony first and was given the name afterwards. But you wouldn't have derived that chord originally based on the name itself. More correct term would be minor major sixth


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## millionrainbows

The thing to remember about classical vs. jazz is that jazz musicians need clarity, and practical answers and solutions. Classical musicians do not; they simply follow the notation of what they play, and are not "paid to think". They are "paid to follow tradition."


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