How to Write a Bass Line for Your Song

Estimated reading time: 7 minutes

Whether you’re into hip-hop or hoedowns, acid jazz or nu metal, a great bass line can be a song’s bedrock and rocket fuel. Bass lines serve multiple purposes — harmonic, rhythmic, building a mood, and hooking your audience — and there are countless ways to craft powerful and effective bass lines.

There are also a wide variety of great instruments you can use to play your bass line, from upright acoustic basses and electric bass guitars to tubas, cellos, synthesizers, Hammond organs, or even the human voice. The choices are yours and the potential is endless.

What is a bass line?

A bass line is a low-pitched series of notes, rests, and rhythmic figures usually played by a single, resonant instrument. Most of the time, bass lines consist of one note at a time, though bass players, composers, and producers do sometimes throw in low-register chords as well. A bass line can be thought of as the harmonic and rhythmic glue that holds a song together, anchors it, and propels it at the same time.

What makes a bass line great?

Bass lines come in various shapes, densities, and styles, and one size never fits all. Sometimes a single note every four measures makes for a killer bass line. Other times, the bass player can be heard wailing out a froth of 32nd notes, beat after beat. Across all great bass lines, though, some things stay constant.

• The bass line supports the song. Just like a solid foundation holds up a skyscraper, a great bass line lets you build sonic castles on top of it.
• It doesn’t get in the way. Great bass lines gel organically with the rest of the song. You never want your bass lines to feel like they’re battling with vocals, drums, guitars, or any other element for sonic space within the song — or for your listeners’ attention.
• It’s memorable — or invisible. Sometimes you want your bass lines to be iconic, so as soon as people hear those signature notes, they know it’s your song. Other times, the bass line is important glue that holds a song together, but as a songwriter and producer, you want it purely in a supporting role, so subtle and woven into the song’s fabric that listeners might not even notice it’s there.
• It just feels good. What else is there to say?

Key elements of an effective bass line

A bass line can contribute to a song in some key ways.

• Melodic and harmonic. A great bass line can be a beautiful melody of its own; just listen to how Flea (Red Hot Chili Peppers) plays to get a sense of what a strong melodic bass line can sound like. Strong bass lines can also help establish the harmonic texture of a song and make it clear what chords are happening at any given moment.
• Rhythmic. Some bass lines are way more about the rhythm and groove than they are about the specific notes. Many genres feature bass lines that make you want to jump around or pump your fist, even if it is just repeating the same note over and over — or if the tone is too crunchy for you to even tell what note is being played. Speaking of which…
• Tonal. Sometimes, a bass line can add a vital element to a song’s tonal character. Is the bass part for your song played with beautiful, rich, contrabass legato, with all its lush harmonics — or is it a fuzzed-out sine-wave synth part meant to increase tension and intensity? It all works, and it all depends on what you want your song (and bass part) to accomplish.

Music theory and your bass line

Crafting a strong bass line is ultimately about what sounds and feels right, and knowing your music theory can help you get there. Here are some elements of music theory that can help you write bass lines.

• Chords. The more you know about how chords are built, the more fluent you are in how to move from one chord to the next, and the more comfortable you are with chord changes, the more choices you’ll have to craft a bass line.
• Scales. Learning about which scales usually sound the most natural and powerful over which chords will give you even more tonal tools to work with when you write melodic lines and your bass parts.
• Passing tones. Sometimes, it sounds amazing to choose notes that are not strictly in a chord or its corresponding scale, but which serve as a bridge between those notes. You’ll hear these sorts of notes all the time in jazz, for example, but passing tones can be useful in nearly any genre of music.

Even the most perfectly-written bass line won’t work well if it isn’t played with the right feel and groove. Bass players often talk about “playing in the pocket” and locking in with the drummer and the other members of the band. As you play or record your bass lines, pay attention not just to what you’re playing, but how you’re playing it. Playing your notes just ahead or just behind the beat, for example, can make a huge difference in how your bass line impacts the song.

Why are bass lines important?

The right bass line can:

• Hook an audience and draw them into the music.
• Help a song move rhythmically by establishing or reinforcing a groove.
• Create space so your song can breathe.
• Fill parts of your song so parts don’t feel empty.
• Create a sense of tension and release that moves your music forward.
• Support whatever element of your song is in the lead at any given point (vocals, guitar solo, etc.).
• Give your song an unmistakable vibe and character.

How to write a bass line

Here are some basic steps to help you get started crafting the bass lines that will make your music soar.

• Be clear on the chord progression. Understanding what chords come next in your song will give you a roadmap over which to write a bass line that will move your song in the right direction.
• Identify the root note and other key notes in each chord. In general, you’re not going to go wrong by just playing the root of each chord from your song’s beginning to end, though there are many great ways to elaborate and evolve your bass lines from there. One good strategy is to identify what the third, fifth, and seventh (if it’s a seventh chord) for each chord are, and then weaving those choices into your bass lines.
• Experiment with different notes outside the basic chord tones. Many great bass lines use lots of roots, thirds, and fifths for each chord, but also explore both harmonious and dissonant choices beyond that. Play around, explore, and see what works for your ears, and your vision of the song.
• Think about rhythm. Sometimes your bass line’s rhythm can be ultra-simple — lots of great rock songs just ride atop bass lines that are straight quarter or eighth notes, for example. Other songs make great use of syncopation, having the bass line lock in exactly with complex rhythms the drums or guitars are playing, or playing rhythms that run counter to those of other instruments. Again, experiment, use your ears, and go with what feels right.
• Think about density. One of the biggest mistakes many producers, songwriters, and musicians make when they’re just getting started is playing too much. With bass lines, try to remember that, in most situations, a little goes a long way. Again, there will be times when super-dense bass parts work like magic — just be sure every note has purpose and enhances your song, rather than getting in the way.
• Do what you feel. Rules are made to be broken, and that applies to bass lines as much as anything. The right bass line is the one that you feel propels your song in the right direction. Have fun and groove hard.

It’s not all about the bass

Once your bass lines are recorded, your music is mixed and mastered, and you’re ready to share your music with the world, Disc Makers has all the CD and vinyl packages you need to make your music look and sound its best.

Related Posts
When the bassline makes the song
The genius of Paul McCartney’s basslines
Recording bass guitar — Tips from a veteran producer
John Gustafson: the second most important bassist to come out of Liverpool
Who says it’s impossible to sing and play bass?