Naming chords in relation to keys/modes

Quick question that has been bugging me for a while.

Are chords names always derived from the major scale?

By that I mean do I always use the major scale to decide what a chord name is.

I have also seen chords (in jazz mostly) written like Imaj7 or a IV maj7, and so on. Does that mean that I am forming those chords from the mode of the key I am in so, for simplicities sake if I was playing in C major, the Vmaj7 would be a Gmaj7 chord formed from the steps of the mixolydian mode.

Or does it just mean I am playing a normal maj7 chord just using G as the root. To tell you the truth I am not even sure what notes are in a maj7 or how one is formed. I just sorta picked it. I'm sure I've played it I just don't pay much attention.

I am trying to get into playing jazz and I want to know my chords really well. I understand the concept behind chord creation and all that I am just not sure what a major 7 would be, considering in the major scale the 7th interval is half a step under the root, unless it is just talking about a major chord (i-iii-v) with a 7 slapped in there, and a min7 is just a minor chord with the same. That would make sense.

Anyway I am just wondering about chord naming because I am not sure if I should be naming them and creating them based on the mode that corresponds to the root of the key or what. This seems particularly relevant with augmented chords since the order of the notes may change depending on where you are playing them in the progression. So a A7 add 9 isn't always the same shape depending on the key since the 9th interval is going to be different depending on the key and chord progression your playing in.

Anyway. I guess that was kinda long winded for something rather simple. Just something that has been bothering me, hope I can clear it up and move on.

Originally Posted by: Drew77Are chords names always derived from the major scale?[/quote]
Chords are named by the interval relationships of their notes.

Like scales, all chords have specific formulas. All chords that have a note, another note a major third from the first note, and a fifth from the first note, are by definition major chords.

C-E-G = C major chord
C#-E#-G# = C-sharp major chord
D-F#-A = D major chord
And so on.

All chords that have a note, another note a minor third from the first note, and a fifth from the first note, are by definition minor chords.

C-Eb-G = C minor chord
C#-E-G# = C-sharp minor chord
D-F-A = D minor chord
And so on.

Chord formulas are based upon scale formulas.

Major scale:
1 (WS) 2 (WS) maj3 (HS) 4 (WS) 5 (WS) maj6 (WS) maj7 (HS) 1

Major chord:
1 (WS) 2 (WS) maj3 (HS) 4 (WS) 5 (WS) maj6 (WS) maj7 (HS) 1

Major 7 chord:
1 (WS) 2 (WS) maj3 (HS) 4 (WS) 5 (WS) maj6 (WS) maj7 (HS) 1

Look at my tutorial on music theory for more on this concept:
http://www.guitartricks.com/tutorial.php?input=495

Look at these tutorials for major 7th and minor 7th chords:
http://www.guitartricks.com/tutorial.php?input=501
http://www.guitartricks.com/tutorial.php?input=513

Originally Posted by: Drew77I am trying to get into playing jazz and I want to know my chords really well. I understand the concept behind chord creation and all that I am just not sure what a major 7 would be, considering in the major scale the 7th interval is half a step under the root, unless it is just talking about a major chord (i-iii-v) with a 7 slapped in there, and a min7 is just a minor chord with the same. That would make sense.

In order to avoid confusion only use Roman numerals (I, ii, iv, V, etc.) when talking about chord progression.

There are many types of 7th chords. Look here:
http://www.guitartricks.com/tutorial.php?input=479
http://www.guitartricks.com/tutorial.php?input=499
http://www.guitartricks.com/tutorial.php?input=500

As ever it is a matter of formula. However, the dominant 7th is a certain case in which the chord is essentially derived from a mode (the mixolydian). 7th Chord Forumulas:

Major 7th: 1-maj3-5-maj7
Example: Cmaj7 C-E-G-B
Minor 7th: 1-min3-5-min7
Example: Cmin7 C-Eb-G-Bb
Dominant 7th: 1-maj3-5-min7
Example: C7 C-E-G-Bb

There are also:

Diminished 7th: 1-min3-flat5-double flat7 (or maj6)
Example: Cdim7 C-Eb-Gb-Bbb (A)
Half-diminished 7th: 1-min3-flat5-min7
Example: Chalf-dim7 C-Eb-Gb-Bb (also called a "min7flat5")
Minor Major 7th: 1-min3-5-maj7
Example: Cmin-maj7 C-Eb-G-B
Augmented 7th: 1-maj3-aug5-min7
Example: Caug7 C-E-G-Bb
[QUOTE=Drew77]
Anyway I am just wondering about chord naming because I am not sure if I should be naming them and creating them based on the mode that corresponds to the root of the key or what. This seems particularly relevant with augmented chords since the order of the notes may change depending on where you are playing them in the progression. So a A7 add 9 isn't always the same shape depending on the key since the 9th interval is going to be different depending on the key and chord progression your playing in.

This is a good question! :)

I think you may have things reversed in your mind. For example, A9 always has the exact same formula in every case:

A9: A (1) - C# (maj3) - E (5) - G (min7) - B (9)

Whether or not that exact chord works in the key and progression you are playing depends upon the key, progression and sound you are after. For example in the key of D major it works fine. This is because all those notes are found in D major. However if you are playing in D minor, you might want to use an A7flat9 instead:

A7flat9: A (1) - C# (maj3) - E (5) - G (min7) - Bb (b9)

Because the B-flat matches the notes of D minor better. Of course, you'd be altering the D minor to D harmonic minor in order to get the C-sharp, too!

But the larger point is that the chord formulas are what they are. They do not change based upon key signatures and progressions. In contrast, certain chords will fit in certain keys and progressions better than others, but only because of their formulas in the first place. Make sense?

Hope this helps. Let me know.

Thanks Christopher. That just about nails it and clears up a lot for me.

It's nice to have someone here who is so knowledgeable and not only that great at explaining whats going on.

I have a horrible time trying to explain music theory to people, probably because I really don't fully understand it, but you always do a great job.

Thanks man.

Originally Posted by: Drew77Thanks Christopher.

You are quite welcome.

I also neglected to deal with another crucial part of your question. When you have a symmetrical chord, an augmented or diminished chord, you name it by it's function.

For example, let's say you are in A minor. Then you alter it to A harmonic minor so you can play a IIIaug chord, the Caug. Since Caug is symmetrical you can choose anyone of it's notes to name it by:

Caug: C-E-G#
Eaug: E-G#-C
G#aug: G#-C-E

In a case like this you use the letter that reflects the chord's function in the song: What happens after the augmented chord? Where is it leading the music?

If you are going to an F major (or minor),then call it a Caug because it is acting as the V of F.
If you are going to a A minor (or major) then it's an E aug, V of A.
If you are going to a C# minor (or major) then it's an G# aug, V of C#.

This is because augmented chords usually function as V chords (or secondary dominants of some kind). Diminished chords are usually vii chords, which is also a dominant function, but a half step below the next root instead of the fifth of the next chord.

Many classical and jazz composers frequently used diminished chords to modulate to different keys by using this technique.

For example, let's say you are in A minor. Then you alter it to A harmonic minor so you can play a vii dim7 chord, the G#dim7. Since G#dim is symmetrical you can choose anyone of it's notes to name it by:

G#dim7: G#-B-D-F
Bdim7: B-D-F-G#
Ddim7: D-F-G#-B
Fdim7: F-G#-B-D

Now you can go to:
C major or minor from Bdim7.
Eflat major or minor from Ddim7.
Gflat major or minor from Fdim7.

Neat, huh? :)

If there is not any tonal function happening, then simply name it so it reflects the mode you are in and try not to duplicate musical letters if possible.

OK, there you go!