A diatonic scale is a collection of 7 notes with specific distances between them. In keeping with the minimalist approach to music theory, and moving from smaller pieces to larger pieces, I prefer to think of a scale as a collection of 7 chords. Each scale position can give us a chord, simply by stacking thirds from that position.
For example, we already know our Major Scale gives us a major triad across positions 1 -> 3 -> 5. But we can do this for each position.
Let’s take a look at the Universal Major Scale Shape. I’ve moved the root to G so the bassists can keep up with the extensions, as well to demonstrate that the root doesn’t change the shapes we’re discussing. What’s true for C Major is true for G Major. Guitarists will of course shift the upper rows as they dip into the top two strings.
The primary scale tones occur across three strings in this shape, however to play each chord in the scale we need to tie in some extensions. Remember that the 9th is the 2nd from the next octave, the 10th is the 3rd, etc.
Chord Positions within a scale:
|I Chord||1, 3, 5|
|II Chord||2, 4, 6|
|III Chord||3, 5, 7|
|IV Chord||4, 6, 8|
|V Chord||5, 7, 9|
|VI Chord||6, 8, 10|
|VII Chord||7, 9, 11|
This shows us we have 7 chords for each scale. 3 major, 3 minor, and 1 diminished (the VII chord). The Pentatonic Scale can be created from what’s left, the “black keys” in the scale, or it can be begun from any position. The Pentatonic version of any scale, is that scale with the tri-tone removed. In Natural Minor, we have the tri-tone at 2 and 6. In the Natural Major scale, we have the tri-tone between 7 and 4. Once we get to modes, experiment with making pentatonic modes by identifying and removing the tri-tone.
The overlap between chords here is also apparent. We see that in any given scale, the III chord contains most of the I chord with the addition of the I chord’s natural 7th. This is also true for II and IV, VI and III, etc. If you were wondering about how “chord substitutions” work, this is one possible avenue. If you play the III chord over the I chord, you get all the benefits of the I7 chord with some added flavor from the different voicings occurring simultaneously.
Continue experimenting with these Scale Chords, and how they overlap and intermingle with each other. When we begin discussing Chord Progressions, and we discuss the I IV V progression, we’re describing these exact chord positions from a given scale.
Let’s take a look at the Natural Minor Scale with it’s extensions as well.
None of the math changes here, we still want 1, 3, 5 for the Primary Triad, which will be Minor in this case. Many people will try to navigate this entire scale when presented with a G Minor Chord, however by understanding the nature of the Scale Chords we can focus our efforts on perhaps the I, III, and VI chords within the scale when we want to avoid unnecessary color tones, but also don’t want to be locked into just 1, 3, and 5.
Every mode of the Ionian Major scale will consist of these chords, just in different orders. For example, in Major, we see that I, IV, and V are all Major Chords. In Minor, I IV and V are all Minor. However, in Dorian, I and V are Minor while IV is Major. We haven’t altered any pitches from the relative Major or the relative Minor, but we’ve dramatically changed how progressions will sound.
The Harmonic Minor scale is built from the Minor Scale, but has a Major 7th instead of a Minor 7th. The Melodic Minor Scale is the same as the Harmonic Minor Scale, but we now swap in a Major 6th instead of the Minor 6th as well. You may see people refer to “ascending” and “descending” versions of Melodic and Harmonic Minor. This is because the top half of the scale now looks Major, so some people prefer to hop back into Natural Minor when ascending these scales to provide that minor tonality.
The Harmonic Minor and Melodic Minor scales are where we see our first naturally occurring Augmented Chord ( 1 3 5# ) in the III Chord position. In this case, the scale positions being ( 3, 5, 7 ), or the Minor 3rd, The Perfect 5th, and the Major 7th from our root.
Guitar and Bass Practice
As SOON as you’re comfortable with the 3 string Universal Scale Shape, begin practicing this same scale across 2 strings, 4 tones per string. Keep track of good anchor points here, learn where the 5th and Octave is on different strings so you can keep yourself from getting locked into a single position on the fretboard.