Jazz Guitar Chords Theory 1 (formulae)

[BigSteve]

Hi guys, this is a real noob question but I have to ask!

In the above lesson, we learn the formulae for constructing major, minor and diminished chords. I understand the theory behind the major chord starting from the first degree (root) of the scale to be a major third then a minor third.

But wait! When we move to the second note of the scale the formula changes to minor third then major third. Same for the third and the sixth. What's all that about? Why doesn't it stay the same all the way through?

If this is one of those situations that we just have to accept as a universal law then fine, but I'd really appreciate it if someone could explain it as if to a child, please.

Am I on the right track by thinking it's related to the number of steps between the notes in a scale?

Using C Major, there are two whole steps between the root and the third (equates to a major third in chord construction) but only one and a half steps between the third and the fifth (equates to a minor third)

Moving up a degree to D Major, there's only one and a half whole steps between the second and fourth of the scale (minor third) and then two whole steps between the fourth and the sixth.

This works for the rest of the chords and degrees where [1 3 5] and [1 b3 5] applies so am I thinking along the right lines?

Do I think too much?

Steve

[ksjazzguitar]

Originally Posted by BigSteve

...I understand the theory behind the major chord starting from the first degree (root) of the scale to be a major third then a minor third....When we move to the second note of the scale the formula changes to minor third then major third. ... Why doesn't it stay the same all the way through?

Because it is being constructed from the notes available in the major scale. If we move to the key of C (no sharps or flats) it is clear. The chord built of the first scale degree will be the first, third, and fifth notes of the scale: C, E, G. The distance between 1st and 3rd is your M3 and the between the 3rd and 5th is a m3.

But when we move to the second scale degree and take the first, third, and fifth notes relative to that note but staying in the C major scale, we get D, F, A. Now the distance between the 1st and 3rd is a m3 and the between the 3rd and 5th is a M3. The intervals are different because we are starting at a different point in the scale. The intervals would only be the same if the second chord were being built off the D Major scale.

Originally Posted by BigSteve

Am I on the right track by thinking it's related to the number of steps between the notes in a scale?

Yes, interval or "number of steps" are just too different ways to measure distance.

Originally Posted by BigSteve

Moving up a degree to D Major, there's only one and a half whole steps between the second and fourth of the scale (minor third) and then two whole steps between the fourth and the sixth.

But there is your misunderstanding. You are not moving up to D major. The D major scale is D E F# G A B C# D. The exact same relationship will hold true for D major, but that's not what we did. We went to the second scale degree in C major - a big difference. The goal here was to find all the triads that could be build out notes of the C major scale.

Originally Posted by BigSteve

This works for the rest of the chords and degrees where [1 3 5] and [1 b3 5] applies so am I thinking along the right lines?

The 1 b3 5 formula only applies if you are starting with a major triad. So, if I want a ii chord in C, I can either start with the C major scale and take the 2, 4, and 6 scale degrees (1, 3, 5 relative to D) or ... if I know that it is going to be a Dm, I can start with a D Maj triad (D F# A) and lower the third to get my D F A.

Both systems (and others) will get you the right answer. I know it is confusing at first, but keep at it, it will make sense.

Originally Posted by BigSteve

Do I think too much?

I don't think that there is such a thing.

Peace,
Kevin

[BigSteve]

Thanks so much for sifting through all that, I know how frustrating it can be to explain concepts in simple terms sometimes.

Now I'm clear on a few things I realise I could simply have asked, 'Does the interval between the notes of the scale in a particular position have a direct bearing on the interval between the notes in the triad?"

Once the penny dropped that moving to the second degree of the scale is rather different to moving to a different key I was much happier. Why I would WANT to move to a different scale position whilst still in CMaj is a question for another time.

I do actually have the Mark Levine book and I'm looking at it now. I was at work and felt I needed to ask the question. Still, I'm grateful for you answering it, Kevin.

Regards,
Steve

[gingerjazz]

Hey big steve mark levines book is a fantastic book but depending on your level you might want to consider finding a more basic music theory book.I have just noticed youare in manchester, i am in huddersfield.I am currently working through my popular music theory exams in association with the London college of music and the registry of guitar tutors.I study from home using their amazingly well written down to earth hand books.If you would like to know more about this please ask and i would be glad to tell you more about it.peace to you man.

[BigSteve]

GJ, thanks for the heads-up. I was doing a bit of the ABRSM Jazz course a few years ago, but life got in the way.
I'll see if I have the material still lying around.
If not, I'll get in touch about the study course you're doing.

Thanks again,
Steve