Theory: Some Chord Questions

[Fretz]

Hey Guys

I've be studying some music theory and just wondering why a 9 chord isn't a 2 chord, a 13 chord isn't a 6 chord and an 11 chord isn't a 4 chord, etc?

I think it's somethng to do with 3 and 7 notes n the chord but I'm not sure.

Would appreciate any help with this!

[vroomery]

Yes. A 9 is 9 chord because of the presence of the 7. If there was no 7 it would be a 2. This is important because when you call it a C9, you imply a minor 7 (Bb) and when you call it a CM9, you imply a major 7 (B).

[woodchuk]

Right - as vroomery said, the 9th, 11th, and 13th chords are all extended chords. This means they are all built off the dominant seventh chord as the base. The lowered seventh of the dominant is present in all the above chords. If the seventh is not present, you essentially have a major chord with either a 2nd, 4th, or 6th added to it. In this case, the suffix add2, add4, add6 is tacked on to the end - like Cadd6. This would imply a C major chord with an added A note in the same octave as the C root (spelled C E G A). If the A was in the next higher octave, we'd call it a 13th, so the chord would be Cadd13 in that case. Remember that any chord named X7, X9, X11, or X13 (where X is any root note) is at heart a dominant chord, so it needs a lowered, or minor, seventh (Bb in the key of C). A major seventh, ninth, eleventh, or thirteenth will have the major seventh (B in the key of C).

[Fretz]

Thanks a lot of clearing this one up guys...it's been bugging me for a while :)

[woodchuk]

You're welcome! A point I forgot to make is that in the case of the 6th, technically the term "add6" is a misnomer, since adding that note to the major triad produces the formula 1 3 5 6 (where each number represents the degree of the major scale to be used in the chord). This is the definition of a "major sixth" or just "sixth" chord, notated as a 6 (a minor sixth, notated as m6, is equivalent to the 6th added to a minor chord, so Cm6 is C Eb G A). Note that the minor sixth chord does NOT contain the "lowered sixth" of Ab, as is the case with the minor seventh and the lowered seventh note (C Eb G Bb in the key of C). The 6 is a little odd in that respect. C Eb G Ab would be considered a 1st inversion Abmaj7 chord, or Abmaj7/C.

To get back on track, C E G A is technically a C6 chord, not a Cadd6 (as long as the A is in the same octave). If not, it would be more descriptive to call it a Cadd13 to indicate that the A is an octave above the root. But a lot of times, you'll just see any chord with those combinations of notes over a C root notated as a C6. Just an aside, as if things weren't already technical enough. :D Chord naming isn't an exact science, in case you haven't guessed. Hope I haven't made your head spin!

[vroomery]

Yeah, the thing about chord naming is that there are some undisputed methods of nomenclature, but a good player will voice things how he wants to voice them to sound the best to his own ear. For this reason, saying that something is a Cadd13 is usually not necessary depending on who's reading the chart. This is especially true with keyboard.

[Fretz]

The pressence of the 7 or dom7 in a chord effects what we call it.
For example as woodchuk and vroomery mentioned: "A 9 is 9 chord because of the presence of the 7".

But, does the presence of the 3rd in relation to other notes make a difference?
For example if the 9 (or 2) appears before/after the 3rd in the chord...does this make a difference?

[Eric]

Also, just to diverge a little bit (I'm good at that!), how about the super-popular open chord:

E-3-
B-3-
G-0-
D-2-
A-3-
E-X-

From looking at this, it's C-E-G-D-G, right? So why is it usually referred to as a Cadd9? The D is the second of the C major scale, but there's no dominant 7, so the add part is right.

But what makes it a 9? It's in the same octave as at least one of the other notes (G), so why not Cadd2? Is the important part that it's an octave above the E?

[woodchuk]

Also, just to diverge a little bit (I'm good at that!), how about the super-popular open chord:

E-3-
B-3-
G-0-
D-2-
A-3-
E-X-

From looking at this, it's C-E-G-D-G, right? So why is it usually referred to as a Cadd9? The D is the second of the C major scale, but there's no dominant 7, so the add part is right.

But what makes it a 9? It's in the same octave as at least one of the other notes (G), so why not Cadd2? Is the important part that it's an octave above the E?

I'll answer this one first. The name comes from the distance from the root note. In this case, the chord as notated above is called Cadd9 because the D note (on the 3rd fret of the 2nd string) is an octave above the root note of C (on the 3rd fret of the 5th string). Since it's a second that is an octave above the root, it's notated as a ninth. If it were present as the open 4th string in the middle of the chord, it would be called a Cadd2, as that D note is in the same octave as the C root.

[woodchuk]

The pressence of the 7 or dom7 in a chord effects what we call it.
For example as woodchuk and vroomery mentioned: "A 9 is 9 chord because of the presence of the 7".

But, does the presence of the 3rd in relation to other notes make a difference?
For example if the 9 (or 2) appears before/after the 3rd in the chord...does this make a difference?

Not that I'm aware of. Truthfully, it might make a difference in theory, but in practice it may not always be notated that way. In any case, I'm not aware of a situation where it would be notated differently. If anybody knows different, please feel free to correct me.

For example, take an A6/9 chord (X04420). This is spelled A C# E F# B, but as it's actually played on the guitar, the notes are A F# B C# E. That C# is technically a major tenth, as it's a major third that is an octave above the root of A, but you wouldn't see it notated as such in the chord name because it's not an extension of a dominant chord, which is always odd (9th, 11th, or 13th). So you'd just notate that as a major third when naming the chord. Did that answer your question?

[Fretz]

Not that I'm aware of. Truthfully, it might make a difference in theory, but in practice it may not always be notated that way. In any case, I'm not aware of a situation where it would be notated differently. If anybody knows different, please feel free to correct me.

For example, take an A6/9 chord (X04420). This is spelled A C# E F# B, but as it's actually played on the guitar, the notes are A F# B C# E. That C# is technically a major tenth, as it's a major third that is an octave above the root of A, but you wouldn't see it notated as such in the chord name because it's not an extension of a dominant chord, which is always odd (9th, 11th, or 13th). So you'd just notate that as a major third when naming the chord. Did that answer your question?

Thanks again for the info woodchuk!
It kind of answers my question. But what I'm really asking is does the "location" of the 3rd in relation to the other notes in the chord make a difference.

For example: if the 2/9, 4/11, 6/13 appears before or after the 3rd note, does that effect how we name the chord?

[woodchuk]

Thanks again for the info woodchuk!
It kind of answers my question. But what I'm really asking is does the "location" of the 3rd in relation to the other notes in the chord make a difference.

For example: if the 2/9, 4/11, 6/13 appears before or after the 3rd note, does that effect how we name the chord?

Gotcha. In that case, no.