Extended chords

Am13 is not constructed from the minor scale. It comes from the standard A ionian scale where the 6th is a F#. Just think of it as a standard 13th with a flattened 3rd.

For example, in G major, a 13th chord would be:

G B D F# A C E
That would be a Gmaj13... 13th chords are assumed to be dominant unless you specify otherwise.

As Jay mentioned, all chords are built from the major scale. The reason for that is there's only one major scale... there are several minors. You'd end up with Am13 (ignoring for a moment the fact that a m13 chord would have a flatted seventh) being:

A-C-E-G-B-D-F (in A natural minor)
A-C-E-G#-B-D-F (in A harmonic minor)
A-C-E-G#-B-D-F# (in A melodic minor)

It's not exactly convenient to have chords changing spellings depending on the scale you use, so the major scale is the source for all chord spellings.

Thanks alot, I never knew that. So basically all chords are built along the major scale, but on occasion they have altered tones? for example, a minor chord will have an altered 3rd and an alterted 7th but all the other tones will remain the same. As how dominant chords will be based upon the major scale except for the altered 7th? If that's the case that really makes everything alot easier.

Yes, exactly. There's only the one yardstick of the major scale... and when you express chord formulas by number, like 1-b3-5-b7 for a minor seventh, that's always in relationship to the major scale.

Thanks alot Noteboat, I'm always finding crazy new stuff that I learn almost everyday about theory :lol:

but when expressing say

Am7

it is from the minor scale..

A B C D E F G A

yeah you would say, I b3 5 b7 .. .but when working it out, you think of the minor scale and do 1,3,5,7... or at least, you should, as there is no point in memorizing a minor 7th chord notes to go "take A major 7th and flatten 3rd and 7th".

As I said above, there are several minor scales.

It's not very hard to do - for Am7 you're flatting 3 and 7; if you know C-E-G-B is Cmaj7, you know C-Eb-G-Bb is Cm7.

Thinking in those terms is also a great help in dealing with chord alterations.

It's not too hard when you think about it:

Augmented: 1 3 #5
Major: 1 3 5 7
Dominant: 1 3 5 b7
Minor: 1 b3 5 b7
Diminished: 1 b3 b5 bb7

etc.

I've always wondered something though, I've never seen large extensions for augmented, diminished and half diminished chords, in reality i've only seen 4 note diminished chords and 3 note augmented chords. Can you make these into extended chords or is it impossible?

Technically you can extend them but then they would just be a A dim add 9 or something to that effect. It isn't really done as they sound very 'exotic.' The only time i've ever seen it is in microtonal music which is a very acquired taste (in my opinion!).

When you extend dimished and augmented chords you kinda lose their purpose. Both these chords have a very unique and instantly recognisable sound, augmented sounding that lil bit sweeter than a standard major, and the dimished sounding very minor like and dimished due to the stacked 3rds, and extending them you lose this sound somewhat.

Your best bet is just experiment, add notes to them and see how they sound!

The reason augmented and diminished chords aren't extended is that extending them won't make new chords.

For the augmented, every interval in 1-3-#5 is a major third. Go up another major third and you're back at the root!

For the fully diminished chord, 1-b3-b5-bb7, every interval is a minor third. And up another minor third - you guessed it, another root.

The augmented coloration, that #5 tone, is often used as a chord alteration. You might see C9#5 or other variations. The same is true of the diminished sound, the combination of b3 and b5. You'll see it in any minor type chord extension with a b5, such as Cm13b5

Thanks alot once again! I think that solved all of my questions.