Follow this simple step-by-step Hack Music Theory guide for writing great bass lines!
Step 1: Start with the root note of each chord in your chord progression
If you’re working in a digital audio workstation (DAW), then copy and paste the MIDI of your chord progression into your bass track. Now delete all the notes in it, other than the root note of each chord. Be sure not to get confused with any inversions though, cos if you’ve inverted a chord, the root will not be the lowest note. You don’t need to hear the root notes, just see where they change, so mute them all now. You’ll also have to move them down an octave or two, as your chords would have been higher pitched than the bass. These muted root notes show you the harmonic rhythm, which is the template you’ll write your bass line over. If you’re doing this old-school with a pen and paper, then just write down the root note of each chord, and you’re ready to start. The root notes in our E Dorian chord progression in this video lesson are: E → B → G → A → D
Step 2: Play around with a rhythm on each chord’s root note
Listen to your chord progression, really listen, it will tell you what kind of bass line it wants to sit on. Our harmonic rhythm is rather slow in our chord progression, so we imagined a bouncy bass line underneath to contrast and enliven it. We came up with a little 5/16 over 4/4 polymeter as our rhythmic motif (i.e. a short musical idea). Remember to always be hunting for motifs, as they’re the gold that elevates a great melody to new heights! Our little polymeter motif gave the bass line a super syncopated feel from structurally accenting (not randomly accenting) off beats.
Step 3. Break up all melodic movements of a perfect 4th and perfect 5th
These are perfectly vibrating intervals that sound way too similar to each other, and are therefore very boring. We need to break up these melodic movements, by adding a note in between. The most thrilling part of doing this is actually the unpredictable and magical detours your melodies will take, which would never happen if it weren’t for these boring intervals needing to be spiced up. We had a perfect 5th (7 semitones) between our E and B, and a perfect 4th (5 semitones) between our A and D, which we fixed with an exciting detour. For more on this vital step, refer to my Melody Checklist. I spent ages pouring everything I know about writing melodies into an ultimate checklist, so if you want every melody you ever write to be a great one, use the Melody Checklist in my Hack Music Theory for Songwriting & Producing PDF.
Step 4. Move some more notes off the roots
Bass is the foundation of music, upon which everything else is built. So, a great bass line needs to provide stability by centering itself around the root note of each chord. If this is all the bass does though, it turns into a mere frequency, not an instrument adding value to the music. This is why we need to create moments of instability by moving off the roots and playing some other notes in the scale. Too much stability will make your bass line boring, but too much instability will make your musical foundation weak and unable to hold all the chords and melodies above it.
And there you have it, a great bass line in four easy steps! Over to you now, so have fun writing great bass lines, and be sure to connect and let us know how you get on with this hackwork. Until next week, happy songwriting!
Ray Harmony
Music Teacher
Victoria BC, Canada
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