I have said many times, basslines don't just happen...they are built. They are the product of music fundamentals, playing experience and musical insight. Therefore, bassline construction consists of a process. One that looks at the line from the bottom up and takes into consideration your inspiration and the line’s effect on what the rest of the band plays
Every bassline consists of harmonic, melodic, rhythmic and dynamic components. All of these need to be thought out and addressed. The balance of all of these components will yield a line that says what you want and melds seamlessly with the rest of the players.
Let's look at an exercise...
Consider the following eight bar phrase:
| Cm7 | G7 | Cm7 | Ebmaj7 | Cm7 | G 7 | Dm7 | G 7 |
Understand, for this exercise, you need to proceed slowly and methodically. This is for two reasons: to teach you the skills needed to build basslines and to avoid using any of your comfort areas or home licks (see my blog post on "isms"). The goal is to train yourself to create something new every time.
The first thing to do is to determine the harmony. What are the notes of the chords? Not finger patterns, the actual notes! What harmony do you want to use: roots only, roots and 5ths, arpeggios, pentatonics, blues scales, etc.. Understand, you can vary this throughout the phrase as desired. You can even change it over subsequent repeats of the phrase. It all depends on how you want the line to evolve.
Second, determine the tempo and groove or rhythm. Now, these may already be prescribed by the style, composer or band leader. If not, choose them on your own. For the sake of this exercise, you can cop them from a tune you like just to get started.
Next, determine the melody or "path" of your bassline. This can be prescribed as above, but often can change as the bassline evolves. By altering the bassline's harmonic environment (what scales, arpeggios, etc.), note density ("busy-ness"), path (whether it goes up, down or stays level relative to what the other players are doing) and use of different pitches a bassline can truly tell a story .
One area many players don't put enough effort in is how the bass line links the chords together. Often, it is these”linking” notes that truly make the bassline melodic. This need not be complicated or notey, but it needs to be thought out. These notes help the chords move through the progression and can really set the bassline's "mood". This, to a high degree is, of course, a walking line (see my post on walking lines).
Lastly, add the dynamics. Dynamics are so underused and can sometimes mean the difference between an exciting line and a boring one. Dynamics can, for example, help emphasize lyrics, build tension before a solo or delineate between verses and choruses.
Make all your choices slowly and deliberately. You are developing a skill that will help your ideas come through. Make several basslines making different choices. You will see that there are MANY ways construct a line and each has its own character. Have someone play the chords while you play the lines. You can hear what your choices do for the line and build your experience and knowledge. Use this procedure to construct or augment other basslines. Understand, this skill requires a lot of repetition to master. As you become more proficient, your basslines will be built more quickly and efficiently until you can do it "on the fly".
Thanks to Randy Snell for suggesting the topic of this mini-lesson
Lots of luck...feel free to contact me with questions...