I came across this very interesting video master class by pianist Dave Frank on playing outside the changes. He describes his master class:
In this advanced master class will explore various ways of improvising melodic lines that go outside the chord changes. We’ll use a basic 1-4-5 blues progression and look at 4 different ways to approach this more advanced way of playing. The general concept of playing lines outside the changes is to suspend the underlying chord progression as a basis for linear improvisation for a period of time, improvising during the suspended measures using a superimposed concept, mode or progression.
In his video Frank goes through three basic techniques you can use to play outside the changes, superimposing a short melodic pattern transposed to different pitch levels a second or third apart, using different modes selected for the amount of harmonic tension over a particular chord progression, and using particular scales, such as whole tone or diminished scales, that are intentionally ambiguous.
It’s a very detailed introduction to playing outside of the changes and there’s a lot of good stuff in there. It’s inspired me to go back and start working more on this aspect of my own improvisation. Take 40 minutes to watch Frank’s video and try some of these ideas out.
