Superimposing chord changes is one way of regulating dissonance in our phrases. This approach can help lines sound more modern and interesting. Let’s look at a couple of ideas to see how this can be accomplished.
If we have a progression in one key we can step out to a distant key in order to create a very noticeable change in dissonance. If we step out to a closely related key the effect may not be as noticeable and may not come off sounding as effective. So let’s establish what keys are generally distant from one another versus close to one another.
The keys that tend to be most distant are a half-step, major third, minor third, and tritone from the original key in either direction. In general, this is the case is especially true if the tonal quality is the same as the original key. For example, if we are in the key of C and play notes from the key of E (a major third), then we will have a relatively outside sound. If we play in E minor, then it will sound relatively inside.
So specifically what can we do to use these ideas? Let’s take the ii-V progression in C. We can superimpose a ii-V progression in E onto C by playing a phrase on F#-7 – B7 while the harmony is suggesting D-7 – G7. This will ramp up the dissonance. We can also weave in and out of the two progressions in a variety of ways. We might play F#-7 – B7 – D-7 – G7 or F#-7 – D-7 – B7 – G7. There are several combinations that we can come up with.
We want to remember to bring these concepts into our practice sessions rather than thinking of them in a performance situation. if we think too much without a lot of history of practicing the material, then we will create a gap in our playing. Time will suffer and it will be hard to stay in the moment. If we practice hearing how the ideas sound, they will emerge naturally.