One of the most important musical structures of the last 100 years is the twelve-bar blues. Let's look at a simple form of this in the key of A major:
12 bar chords sequences similar to this are frequently used as a basis for improvisation. As in our previous lesson on the pentatonic , we can use one form of the pentatonic scale which will sound effective over the whole chordal structure. This time, however, we don't choose the A major pentatonic, since this does not produce the correct blues sound. Instead we use the A minor pentatonic: A, C, D, E, G.
Here's a possible improvisation using only these notes:
Now give it a try. Remember to play with a swing!
You may wish to concentrate on the right hand improvisation before playing both hands. In either case, however, your improvisation will sound really effective with this backing track:
Though these notes sound quite effective over our improvisation, we can better respond to the chord changes by also changing our pentatonic scale. The chords and their related scales are as follows:
A7: A, C, D, E, G
D7: D, F, G, A, C
E7: E, G, A, C, D