Is the chord of the notes C E G Bb A, a C7th add 6th or is it a 13th? The main point of my question is do you need the 9th and the 11th to diffrentiate?

And is that critical? In other words are music exams on these points very precise?



4 Answers 4


In real life, anything above a 7th chord must contain that 7th note - be it a major, minor or even diminished seventh. (Augmented don't count here!)

So, a 9th chord will basically be 1,3,5,7 and 9. If not, it'll be an 'add9' chord.

However, when it comes to 11th and 13th chords, things can get very muddy. Let's face it - a C13 could contain C,D, E, F, G, A and B/B♭! Which may be possible to voice nicely in an orchestra or bigband, possibly on piano, impossible on guitar.

So things can and do get left out. An obvious is the 5 (unless it's +5 or -5), but that still leaves potential clashes of other notes. With 11th and 13th chords, it's best to listen carefully to what voicings will work in each circumstance - and omit notes accordingly.

11th chords often miss the 9th note (and/or 5th), and 13th chords can miss the 9th and 11th notes, without losing their recognisable sound.

As far as exams are concerned, sometimes they're more concerned with theory rather than practice, so are occasionally in a parallel universe (!) so here, it makes sense to actually ask the question to the board in question. They are by and large very helpful - and there are example test books which will give clues, too.

  • For a theory exam things aren't muddy: 7:1,3,5,7, and 9:1,3,5,7,9, 11:1,3,5,7,9,11, and 13:1,3,5,7,9,11,13. But if the exam asks, which of the notes are more important and which of them can be left out ... Then you might take the often used guitar "C13" fingering 8-x-8-9-10-x, which only has four notes in it, even though a C13 is supposed to have seven. :) Nov 17, 2019 at 10:49

Short answer: in a music theory exam question asking what notes there are in a chord named "C13", a C13 has the notes 1,3,5,(flat)7,9,11,13, i.e. C, E, G, Bb, D, F, A. In other words, C13 is "C11add13", C11 is "C9add11", and C9 is "C7add9".

However if the music exam asks how a C13 chord might actually be played in practice, then I'd say that the importance order of the notes when a C13 is written to be used as a dominant or blues chord is, from most important to least important: 7, 3, 13, 1, 9, 11, 5.

It's somewhat subjective, but I think most people would agree on at least leaving out the 5th. The importance order (of which some people may disagree in some situations) comes from the role and use of the chord. There are basically two essential things that define a chord's harmonic function:

  • (1) is it a major or a minor (or sus4), and
  • (2) if it's a major chord, does it have a dominant seventh or not. (as opposed to major-7th or no seventh at all)

The 13 is a "dominant chord" and it must have a flat 7th. And it's a major chord and has to have a major 3rd. The same applies to a 9 chord, it must have a flat 7th. You can use a 13 chord or a 9 chord as a thicker and jazzier dominant-seventh chord. The 13th can be thought of as the same note as 6th, but the chord is not a 13 if there's no 7th. If there's only a 6th, then it's a 6 chord. If there's a 6th and a 9th but no 7th, then it's a "69" chord which is a thing in itself.

Why do I say the 1 i.e. the root of the chord is only fourth-most important note? It's because the root can often be implied or imagined because of other things, and it's not a so important as a harmony changer. And as a starting point here we have been given a 13 chord! Depending on the style of music you're doing, you might as well consider the root as the most important note. Maybe in some very basic pop you would use just roots instead, but then you would not have 13 chords either.

Here's some rootless blues where 13 chords are played with only the first three notes from my priority list. Root notes are left out deliberately to demonstrate what it sounds like if you leave out root notes from dominant/blues chords.

(Is it "roots" music if roots are left out?)

  • In my experience, there seems to be a strong split between the Jazz and Classical approach to a 13(th) chord. Jazz would just about literally never include the natural 11, only #11. Classical musicians are taught that it includes all the notes by default and some are excluded, either for consonance or technical ability. Jazz musicians are taught that it's a 7 chord with a 13 and probably a 9. Nov 19, 2019 at 17:40

Usually C7 excludes a 6th, while C also can be played as C6.

C713 = C-E-G-Bb-A

while C13 contains the b7 but not necessarily the 9th or 11th. If they have to be played it might be notated.

Mind that that there is always a melody played that may contain an additional note and that this chord assignments are abbreviations also for analysis and not only indicating what may be played. Let your ear decide and play your preferred version.

In a music exam it is up to you to be precisely and you better don’t let come up some doubts about anything even if you are redundant. You can still make a parenthesis or a footmark.

  • Never come across C713!
    – Tim
    Nov 17, 2019 at 8:04
  • Oh, this was a typo! I forgot the B between G and b. Nov 17, 2019 at 8:09
  • I missed that! But still never heard of C713.
    – Tim
    Nov 17, 2019 at 8:11
  • This is very usual in church hymns and romantic pieces. Just imagine a V7 with a suspended 6th (13) in the melody: so,ti,fa ... miredo. Nov 17, 2019 at 8:14
  • I understand the concept, just never seen it written C713. I tend to play this with only 6th (13th) and b7 along with the basic triad, but still call it C13. I think the 9th and 11th are optional - in fact need leaving out in the majority of cases.
    – Tim
    Nov 17, 2019 at 8:37

Generally speaking, the difference between a 6 and a 13 chord has to do with whether or not there is a 7 in the chord. Below are a few examples of chord symbols with the notes of the chord.


C13 - CEGBbA (further thoughts on this below)

Cmaj7 (13) - CEGBA


Cmin6 - CEbGA

Cmin13 - CEbGBbA

Notice how the symbols that include a 13 always have a 7 in the chord and those that include a 6 never do.

Generally speaking, if you don't see the 7 specified in the chord symbol, it indicates that it is a dominant chord (such as the C13 above). This would also be the case for a chord symbol of 9, where C9 would be a C7 with a 9 and Cadd9 would exclude the 7 and wouldn't explicitly imply dominant functionality.

There is some dispute about chord symbols such as C13, where many are taught that they generally include all the notes below the 13, including 9 and 11. Outside of Classical music, it is incredibly rare to find a natural 11 in a 13 chord, though #11 is common in Jazz. I've also found that there is a distinction between a 13 chord and a 13th chord, where 13 is a dominant chord and the quality of a 13th chord is determined by its context. For example, if we're in C major and you see an A13th chord symbol, this would indicate that we are playing or hearing an A minor chord with natural 9, natural 11 and flat 13 (built from Aeolian). Unless you're studying/playing Classical music, you should basically always assume that seeing a chord symbol of 13 means you're playing a dominant chord and you should either avoid 11 or it should be #11.

  • Can you point to a source where "A13" should be taken as a minor chord if the prevailing key happened to be C? I think chord symbols should always be absolute and not in any key at all. If you see a chord symbol, you should be able to use the same guitar chord grip, regardless of key. Nov 19, 2019 at 19:54
  • @piiperi - To be clear, this is not what I generally see and really only seems to apply to Classical music. I can't really recall where I learned that and haven't really found a corroborating source in my limited search just now. Perhaps I am incorrect, as what I have found in my limited search seems to show that 13 is always dominant and anything else will be specified. Nov 19, 2019 at 20:19

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