Theory & Impro Why do extensions have a flat (dominant) 7?

jeremyjuicewah · Dec 10, 2011

Well I just thought it would get your interest. Dont get connected in the new flat till Monday so cant pick up or post very often at the mo. Been delving into theory since I damaged my lip and had a good lesson yesterday but didnt understand it all. Best sometimes to let something go in order that the lesson moves along but I am still stuck with this, using C for the example:
C9 has a flattend 7th, as does C11, C13 etc. Why? What it there to tell me in C9 that the 7th is flattened? Or is it like Cminor, where I just know the 3rd is flat? And then, C add 9. I should know this but I get very confused. If add 9 is the D added to the C chord, why is C9 different to add 9?

Would also like to apologise to someone on here who asked about what the chords above a melody were for in terms of improv some time ago. I gave the most ignorant and uninformed answer. I now know better and even realise to some extent what I do not know. I hope the poor so and so took more notice of the more informed answers over mine.

But goodness, it is VERY interesting.
Best wishe
Mike

aldevis · Dec 10, 2011

C9 has a flattened 7th because it comes from a dominant chord when a tonic chord didn't use to have a 9th.
Cmaj9 has a major 7th
Cadd9 has NO 7th

But these are just conventions... C7#9 should actually be C7b10, but common practice wins.

I hope this helps

Pete Thomas · Dec 10, 2011

jeremyjuicewah;62124 said:
C9 has a flattend 7th, as does C11, C13 etc. Why? What it there to tell me in C9 that the 7th is flattened?

aldevis said:
C9 has a flattened 7th because it comes from a dominant chord when a tonic chord didn't use to have a 9th.
Cmaj9 has a major 7th
Cadd9 has NO 7th

But these are just conventions... C7#9 should actually be C7b10, but common practice wins.

aldevis is spot on. It is just the way it is, not really logical, just convention.

If you think about it, it is just an extension of C7, there is nothing in the nomenclature of C7 to tell us the 7 is flattened, we rely on the modifier maj in a major 7 to differentiate.

This does confuse people who start of with classical theory, who might think of C E G B as chord I7

It'a all confusing until you get used the the conventions, e.g. common sense might make us think Cmin7 is a C chord (C E G) with a minor 7, but we know it's not, it's a Cminor chord with a (minor) 7.[/QUOTE]

Young Col · Dec 10, 2011

Yes that confusion isn't helped by the more traditional learning routes like ABRSM main grades where they are taught as dominant 7ths. Thus a C7 is learnt as a dominant 7th on F major. Same thing of course, but no mention of the (more common in jazz/pop) C7 notation.

However, the traditional way does give the answer. If you work it out as a dominant 7 in F major then it will have a flat B. If you take it as a tonic chord in C major, then it obviously it won't, hence CMaj7.

Tenor Viol · Dec 11, 2011

Young Col said:
Yes that confusion isn't helped by the more traditional learning routes like ABRSM main grades where they are taught as dominant 7ths. Thus a C7 is learnt as a dominant 7th on F major. Same thing of course, but no mention of the (more common in jazz/pop) C7 notation.

However, the traditional way does give the answer. If you work it out as a dominant 7 in F major then it will have a flat B. If you take it as a tonic chord in C major, then it obviously it won't, hence CMaj7.

As someone who has 'gone the classical route' and therefore I'm used to notation like "I7" or "V7" it took me a while to realise that C7 meant "V7" in the terminology I was used to.... which is significant with regard to the 7th.

jeremyjuicewah · Dec 12, 2011

Thank you all. I will slug away at this until the lip heals then I am going to explore improv in practice. I never ever realised how neatly all this stuff goes together.
Cheers
Mike

jeremyjuicewah · Dec 17, 2011

Thanks again all. I have got through that now and I understand.
Mike

rhysonsax · Oct 6, 2015

I was going to start a new thread, but I guess my question is related to this existing thread.

I have seen the chord symbols C7+9 and C7+ and am confused as to what they mean and so what notes are in each chord.

Researching on line gives me conflicting information:

some sites say C7+9 is a C7 with a #9 on top: C E G Bb D# (is this the Hendrix chord ?)
some sites say C7+9 is C9: C E G Bb D
some sites seem to say C7+9 is Cadd9: C E G D (but why is the 7 in the symbol) ?
some sites seem to say that C7+ is C augmented7: C E G# Bb

What is correct (and why can't there be better standardisation of chord symbols) ?

Rhys

aldevis · Oct 6, 2015

C7+9 is usually a misspelling of C7#9
C7#9 is usually a misspelling of C7b10, but let's not get there.

C7+ is usually Caug7 (#5)

But there might be disagreements.

Colin the Bear · Oct 6, 2015

Everything written isn't written with knowledge. Misunderstandings are passed on. Guitar conventions and shorthand sometimes bear little actual relevance to musical theory and harmony. Where a symbol for a guitarist means a shape on the fretboard, the same symbol to a woodwind player is a list of the contents of the chord

"Add" and + mean the same thing in arithmetic. But in harmony short hand + is augmented. And here the confusion starts.

C add 9 ( CEGD) isn't C+9 (Caug9 CEGD#) and C9+ is different again. CEG# D.

C7+9 is a confusing list of symbols. It would seem to be a C7aug5th add 9 or is it a C7add9 written by a mathematician.

Even with reliable trusted sources, typos occur. Adding to the confusion. I'm only just getting to grips with this.

Pete Thomas · Oct 6, 2015

The + should just mean augmented 5th. But sadly it became used (Berkley?) to mean a sharpend 9. hence the confusion.

Aldevis and Colin are right, it is a big confusion and mess.

Some people will say the + has to be before the 7 if it refers to the 5, but who has time to think about that?

So I would recommend you think that the + only refers to the 5 (i.e. augmented 5) and if anyone uses it to mean #9, then they are wrong.

jbtsax · Oct 6, 2015

I can see where C#9 could be confusing. It could mean a C#7 with an added 9th or it could mean a C7 with a #9. It seems that a logical workaround would be to write C+9.

Pete Thomas · Oct 6, 2015

C+9 is C E G# Bb D

Targa · Oct 6, 2015

If 6 was 9 would it be a Jimi riddle?

jbtsax · Oct 6, 2015

Pete Thomas said:
C+9 is C E G# Bb D

I stand corrected oh great Chief of Stuff. 🙂 I've gone back to my Aebersold and now I'm even more confused. What's the old saying, "Things aren't always as they appear to be"?

aldevis · Oct 6, 2015

Aebersold's scale syllabus is sometimes misleading.
Take it with a bit of critic sense.

jbtsax · Oct 6, 2015

So how would one write the chord symbol for a C# dominant 7 chord with a raised 9th? Would it be C##9? Or perhaps C#7#9? By jove, I think I've got it. When the chord name (tonic) includes a sharp or a flat it is best to add a 7 when adding a #9 or b9, even though that is not necessary when the chord name does not include a b or # such as C#9 or Cb9. Oh dear I've lost it again. Maybe you always want a 7 when the 9th is raised or lowered like C7#9 or C7b9, but when the 9 is just 9 then you can leave off the 7 which is implied.

aldevis · Oct 6, 2015

jbtsax said:
So how would one write the chord symbol for a C# dominant 7 chord with a raised 9th? Would it be C##9? Or perhaps C#7#9? By jove, I think I've got it. When the chord name (tonic) includes a sharp or a flat it is best to add a 7 when adding a #9 or b9, even though that is not necessary when the chord name does not include a b or #.

You got it.
C#9 can only mean C# with dominant 7 and major 9.

In the rare case you want no 7th but a #9 (that I'd call b10)
C# add#9

By convention....
If X is the root...

X7
X9
X7b9
X7#9

But if no 7th...
X add9
X add #9
X add b9