The Blues scale is critical to both rock and jazz, although there are some variations between the two genre’s usages. The concept of a “blues” scale is different from most other scales in that there are 2 notes in the blues scale that aren’t tonal to the chord progression that the scale is typically used over.
The blues scale is a six note scale and consists of the following notes: 1, b3, 4, b5, 5, and 7. In the key of A that is A, C, D, Eb, E and G. These notes are typically used over an A7th chord. The A7th contains the notes A, C#, E, and G. The two contrary notes are C and Eb or a b3 and a b5. These notes are what give us the “blues sound”. When used for melody, they may be bent up to the chordal tone or slid from to the adjacent chordal tone.
The blues scale and exercises are here as a pdf document. The exercises are just typical note runs in groups of 3 and 4.
The blues scale can be used in many different ways. The root of the chord is normally played on the downbeat of 1. Either the root or fifth is often best on beat 3. In between, almost anything from the scale works.
The structure of the blues is fairly well-set and doesn’t vary a lot harmonically. 12-bar blues is the most common. It consists of 4 bars I7 chord, 2 bars IV7, 2 bars I7, 1 bar V7, 1 bar IV7, 1 bar I7 and 1 bar V7.
Now it’s time to practice. Here are 2 mp3 files of blues progressions in A. Just guitar mostly, no bass on the track. Experiment away.