Guitar Theory - Diatonic Triads
Chords:
Diatonic Triads
We touched on diatonic triads briefly in the section on Chord basics, but now that we understand a little more about scales let’s look at them again. In this free guitar lesson we are going to use numbers.
In theory every thing starts with the major scale (Root -(whole step) - 2 -(whole step) - 3 - (half step) - 4 - (whole step) - 5 - (whole step) - 6 - (whole step) - 7 - (half step) - Root). We will assign the numbers 1-8 to each of these notes.
1 - 2 - 3 - 4 - 5 - 6 - 7 - 8(1 again) - 2 - 3 - 4 - 5 -etc.
Remember that 8 is actually 1 an octave higher. (An ‘octave’ is exactly 12 half steps above our starting note, and will be the same note.)
Diatonic triads or naturally occurring triads are the three note chords that are built by starting on each note in our major scale. Using our numbering system we can build our chords like the following list:
Whether or not these chords are majors or minors is determined by the root note’s major scale; not by the scale we are building the chord from. Once again we will use the ‘C’ major scale as an example. The 2nd chord we can build from this scale is D -F -A (2,4,6). The D major chord is D -F# -A because the ‘D’ major scale has an F# in it, not an F. Our formula for minor chords is 1 -3b -5. In the D major scale this would be D -F -A. Therefore the 2nd chord built in the ‘C’ major scale is a minor not a major.
Here’s another example:
The 3rd chord in the ‘C’ major scale is E - G - B. We determine whether or not this chord is a major or a minor by using it’s root note’s (E) major scale.
E - F# -G# -A -B -C# -D# -E
As you can see the chord E - G - B is made up of the 1 - 3b - 5 notes in this scale. This is an E minor chord. Major would be 1 - 3 - 5 or E - G# - B. So our minor or major comes from the ‘E’ major scale not the ‘C’ major scale we are building from.
This works with the rest of the chords in all keys. So all we have to learn is our formula for building a major scale and our formula for building chords from a major scale and we have the ability to find all the diatonic chords in any key.
Here’s an example:
The notes in the Key of A are
A - B - C# - D - E - F# - G# - A
Therefore the naturally occurring chords in this key are:
A major - B minor - C# minor - D major - E major - F# minor - G# dim. - A major
See how easy that was, just use the numbered formula I have above, replacing the roman numerals with the notes of the major scale for the key you want to be in.
So far we have only learned the formulas for building major (1,3,5) and minor (1,3b,5) chords. This is all you need to get started finding your diatonic chords in all keys. (Don’t bother yourself with the diminished chords just yet.) Practice building major scales and finding the diatonic chords by using your guitar neck and the formulas we have learned so far. Start with simple keys and work your way into the harder ones. By using barre chords you can transpose these chord formulas into any key you want without doing the calculating, but I suggest you sit down and go through the different keys. Try a different one each day or maybe each week; but keep working on them. Knowing how to do this will separate the real players from the amateurs, and it’s not hard to learn. Just takes a little time. It will be worth it!
