Improvising a Bass Line
Daniel Stevens
As a form of musical “play,” improvisation often involves significant amounts of iteration and experimentation. Think of a child who begins designing an airplane out of LEGOs. At first, the basic structure is formed, and over time, new bricks are added to create special features. Sometimes, a child must try different combinations of bricks to get just the right result. None of the choices made along the way are right or wrong, but they are all essential steps to getting a satisfying result.
Similarly, improvising a bass line to a given melody is a creative, playful activity that will involve significant iteration and experimentation. As you begin trying different possible approaches, you may find that a simple melody admits seemingly countless possible bass lines.
Before you begin, it is important to remember three functions of a bass line, the last two of which are unique to this line as the lowest in the texture. First and foremost, the bass line should itself be a beautiful and musically appropriate addition to the melody. While defining these criteria is somewhat subjective, for now, it is worth noting that the process of improvising a bass line should avoid defaulting to formulas or patterns. Further, we are improvising a bass line, not just the bass notes to whatever harmonies you think the melody calls for. Often, a good bass line will create harmonic possibilities that you hadn’t considered, so at this stage, it is best to think of the bass line as a second melody that will complement the given melody.
As noted, there are two special functions that the bass line plays. The first is to establish a beautiful contrapuntal relationship with the melody. Contrapuntal writing has a long history stretching from the Renaissance through the compositions of contemporary composers. While counterpoint is sometimes approached as a rules-based compositional practice, the basic aesthetic values of contrapuntal writing, including balance, flow, and independence of voices, are typical across styles. When improvising a bass line in a tonal context, consider some of the musical qualities that are associated with each of these aesthetic qualities:
| Aesthetic Quality: | Musical Considerations: |
|---|---|
| Balance | Does my bass line complement the rhythmic structure of the melody by using similar rhythmic durations?
Does my bass line have a clear overall shape, with points of arrival? |
| Flow | Does my bass line use mostly stepwise/conjunct motion?
Does my bass line approach large leaps with care (often following them by stepwise motion in the opposite direction)? |
| Independence | Does my bass line use different rhythmic patterns from the melody?
Does my bass line establish a contour that is unique from that of the melody? Does my bass line use some contrary motion by sometimes moving in a different direction than the melody? Does my melody establish mostly consonant relationships with the main, structural notes of