Superimpositions are used by all great improvisers, but are often taught as ‘substitutions’ which can be confusing when you are trying to understand how to apply this information while improvising over a tune.
Succinctly put, substitutions are replacements for the harmonic content within a song and are often chosen to re-harmonise the composition in question, working to co-exist with the original melody. On the other hand, superimpositions consist of melodic and rhythmic content that are ‘layered’ on top of the existing harmonic progression.
When using superimpositions, I like to describe these options by thinking of them as ‘layers’ in Photoshop. This is a useful analogy because when superimposing melodic and rhythmic content, you can’t afford to forget about the original chord changes. You must be able to develop this ability to think about multiple options at the same time.
In the example below, I’ve taken a well-known 8-bar chord sequence, consisting of a II V I IV in a major key area, followed by a II V I in the relative minor key.
In the first two bars, I’ve superimposed a rhythmic figure in 3/4, starting on beat one and beat four of bar one, using diatonic 3rds to outline C Dorian and F Mixolydian. This creates a rhythmic superimposition of 3 against 4. In bars three and four, I’ve superimposed some G-7 melodic ideas over the Bbmaj7 and the Ebmaj7 chords. This creates a melodic superimposition that works well to highlight different chord tones and tensions over the original chord changes.
At bar five, I start the minor II V I off by superimposing a C-(maj7) melodic idea over the A-7(b5). This creates another interesting melodic superimposition. Over the D7(b9) chord, I’ve used the D Mixolydian b2, b6 scale, but added tension #9 at the beginning of the line. This isn’t a superimposition per say, but does sound great mixing these different ideas together. Over the Gmin chord, I’ve resolved the line by using b3 to 5.
Superimposition can help to add some different sounding elements into your bass playing and really enable you to get inside of a tune with more effectiveness and clarity. If there are any elements that you are slightly confused about using superimpositions and chord substitutions, then you really need to invest in my book, Functional Harmonic Concepts. This book will answer a multitude of questions about harmony and will really help you to take your improvising one step beyond!
All the Bass!
P.S. Any questions? I’d be happy to help- leave your comments below.