STEP 5: THE BASS LINE

STEP FIVE: writing a bass line

Bass lines play a really fundamental role in most compositions. Bass instruments often help to establish the 'groove' or the rhythmic feel of the piece, highlight the harmonic structure of a piece, and play a crucial role in counterpoint. 

Because lower frequency notes tend to be 'richer' and carry more audible overtones, bass lines tend to be handled slightly differently from other parts of the composition. The are several important devices that tend to be used almost exclusively for writing bass lines.

Bass lines tend to be largely based on chord tones, with an especial emphasis on the tonic and dominant (1st and 5th) notes of a chord - particularly on strong downbeats (typically 1 and 3). In many styles of music, the bass is also used to imply 'passing chords' and create forward movement from one chord to the next.

Bass parts also tend to be easier to hear than the 'inner voices' in harmonised lines, so the interplay between the bass part and the main melody line can be crucial. Polyphonic music often heavily relies on a 'conversation' between the bass line and the lead part, with other voices playing a supporting harmonic role.

You can also really spice up your chord progression by using good voice leading ideas in your bass line to create chord inversions, or imply or create other chords.

Here are some ideas you should experiment with when creating your bass line:

In the example below, I've used a simple motif (and a couple of inversions) to create an effective bass line for my composition. It features an ostinato line, and the step-wise movement on beat 4 of each bar sets up the following chord change.