More Triads

By playing every other note in the scale we obtain 7 triads - three major, three minor and one diminished. Playing the notes in a triad simultaneously we get chords. This is called the harmonization of the major scale - we have obtained a family of chords that derive from a certain scale and thus work together.

This is the chord formula for every major scale: I major, II minor, III minor, IV major, V major, VI minor and VII diminished. In the context of four note chords we will be altering a little bit this chord formula.

Superimposing the major triad over the corresponding major chord will produce the most consonant sound possible. By playing triads from the same family - for example, instead of D major over the D major chord we could play F# min or B min - we can still achieve a consonant sound without being too obvious. The three triad families are (I, III, VI) - (II, IV) and (V, VII).

I encourage you to play with these triads and use any of them over any chord. What sounds consonant to me might not sound to you. Nevertheless, being able to hear them and being familiar with them will help you take informed decisions while improvising.

Intervals

This week's subject is intervals. By repeating an interval and combining intervals you can obtain a structured melodic sound.
Practice carefully the following exercises in all positions and all scales.

The Major Scale

Improvisation, and music in general, is based upon the idea of repetition and variation. It's underlying psychological truth is the fact that people are able to process only small chunks of information. In order for such a chunk to become interesting it has to be presented repeatedly, but each time slightly different, lest it became boring.
Thus arises the idea of structure: the blueprint of repeating and varying musical ideas.
The first important implementation of the idea of structure in music is the concept of playing subsets of the available notes. These are called scales. The most relevant scale to the western music is the major scale, characterized by the following interval formula: whole-tone, whole-tone, half-tone, whole-tone, whole-tone, whole-tone, half-tone.

Here is the scale in all positions on the fretboard: