The Modal system:
Harmonization of the major scale
What does it mean to harmonize? First of all you need to know that a scale, of
whichever type, has the dual purpose to contribute to the creation of the melodic lines, and also to create the chords that make the harmonic base of a song. On one hand we have the possibility to create triads, which are 3 note chords constructed by superimposing one third upon another third, and on the other hand we can develop both melodies and harmonies that are more and more complex depending on the type of analysis done on that scale. |
The modes: Some history... |
It's necessary to clearly understand the basic construction of the scale, which is a succession of steps and half-steps. As usual, we will use the scale of C major. We can now see the scale and its composition of degrees.
| C | D | E | F | G | A | B | C |
| I° | II° | III° | IV° | V° | VI° | VII° | VIII° |
Up to here no problem. Now we do it so that every note of the scale is put in the first place of a succession of notes in C major. For example, you can start the succession of notes with the II° (D note) followed by the others notes in series (E, F, G, etc).
| D | E | F | G | A | B | C | D |
As you can see, the series of notes has been moved forward one degree: instead of starting from C we start from D. At this point we develop the system on all the notes in C major.
| C | D | E | F | G | A | B | C |
| D | E | F | G | A | B | C | D |
| E | F | G | A | B | C | D | E |
| F | G | A | B | C | D | E | F |
| G | A | B | C | D | E | F | G |
| A | B | C | D | E | F | G | A |
| B | C | D | E | F | G | A | B |
Now we can more easily understand the meaning of the term mode. In the previous table we saw seven different kinds of scales and seven new interval sequences, that come from every degree of the main scale. From this we can also underline the substantial differences that exist between the tonal system and the modal system.
In the tonal system, the root is the tonal center in its major or minor mode.
In the modal system, every degree of the scale becomes the root. For example, the D note, which is the second degree in the C major scale becomes the first degree, and therefore the root of its mode (dorian). Or the G, fifth degree in the C major scale, becomes the first degree in the G mixolidian mode.
With this system we have basically created a series of secondary roots. They are roots because, as just seen, each of them is the first degree in its own modal scale. They are secondary roots because, even if they are head of their mode and therefore independent, make reference to the main root (in our case C). The following table shows the development of the modes in C major.
| I | II | III | IV | V | VI | VII | VIII |
name |
||
| 1° | C | D | E | F | G | A | B | C |
 |
ionian |
| 2° | D | E | F | G | A | B | C | D |
 |
dorian |
| 3° | E | F | G | A | B | C | D | E |
 |
phrygian |
| 4° | F | G | A | B | C | D | E | F |
 |
lydian |
| 5° | G | A | B | C | D | E | F | G |
 |
mixolydian |
| 6° | A | B | C | D | E | F | G | A |
 |
aeolian |
| 7° | B | C | D | E | F | G | A | B |
 |
locrian |
