Harmonizing the Major Scale: Using a Number System on Bass
This week, I’m kicking off a new lesson focusing on the foundation of music – the major scale. Read over this lesson and then be sure to check out the video for a demonstration.
Western music harmony is mostly based on the 7 steps of the major scale, and the chords built on the major scale are very common to music. It is important to memorize and transpose these chords, since they cover the bulk of the music you’ll play.
For example, most rock and pop tunes consist of simple chords and “easy” keys, such as C, G, D, Am and Em.
These chords are referred to as “diatonic”, which means they only use the notes contained in the major scale.
Build simple chords on each step of the major scale
Here, we’ll take the 7 steps of the major scale and build a simple chord on each of those steps. These three-note chords are also known as “triads”:
- C E G = a C Major triad, written as C
- D F A = a D minor triad, written as Dm or D-
- E G B = a E minor triad, written as Em or E-
- F A C = a F Major triad, written as F
- G B D = a G Major triad, written as G
- A C E = a A minor triad, written as Am or A-
- B D F = a B dimished triad, written as B0 or Bdim. (Note: this is not that common and is often changed to a G Major triad with B in the bass G/B)
So to build a triad from a scale, you play every other scale note. For example:
- C Major triad: 1st, 3rd and 5th step of the C Major scale (C E G)
- D minor triad: 2nd, 4th and 6th step of the C Major scale (D F A)
- E minor triad: 3rd, 5th and 7th step of the C Major scale (E G B)
Using the triads
So take another look at the chords formed by each step of the C Major scale:
C, Dm, Em, F, G, Am, Bdim
Translate that to the steps of the C Major scale:
1, 2m, 3m, 4, 5, 6m, 7dim
If we only use the Major chords from that group, we get:
C, F, G or the scale steps 1, 4 ,5
Those are the chords most commonly used in blues and rock progressions:
| C | C | C | C | | F | F | C | C | | G | F | C | G |
Or written as numbers (the scale steps) as many studio musicians do:
| 1 | 1 | 1 | 1 | | 4 | 4 | 1 | 1 | | 5 | 4 | 1 | 5 |
Reading (and writing) as numbers is a smart thing to do, because it allows you to transpose to any key more easily, because you’re only thinking about the scale steps.
So thinking in “C”:
| 1 | 4 | 5 | 1 | in C: | C | F | G | C |
And transposed to G:
| 1 | 4 | 5 | 1 | | G | C | D | G |