How to Write Bass Lines: Notes, Rhythm and 808s

“…I started thumping the strings—to make up for not having that bass drum—and plucking the strings to make up for not having the backbeat on the snare drum.”

Mute the bass in a song you love and listen to what’s left. The chords are still there and the drums still hit, yet the whole thing suddenly sounds thin, like a demo. That’s how much work one low part does. Most beginners write it last, in a hurry, and hope for the best. You don’t have to. Learning how to write bass lines comes down to two choices you make again and again, which note and when, and you don’t need to play bass or read music to make either one.

What is a bass line?

A bass line is the lowest part in a song, usually played one note at a time. It does two jobs at once. It tells your ear which chord is playing, because the lowest note colors everything above it. And it locks in with the drums, the kick drum most of all, so the song feels solid and makes people move.

In rock and pop, a bass guitar usually plays it. In electronic music, trap and hip-hop it’s often a synth bass, which is a bass sound made by a synthesizer plugin, or an 808, a deep, booming bass played from a sample. Whatever plays it, you write it the same way. The sound comes second. Get the notes and the rhythm right, and even a plain sound works.

How to write bass lines, step by step

Here’s the whole method in order. Max, the founder of Mix Elite, teaches the heart of it, roots by ear and 808s on the kick, in Mix Elite’s free 4.5-hour FL Studio course on YouTube, below. The bass line lesson starts at 57:46 and the 808 part at 1:16:15. Each step gets its own section after the video.

1. Start from the chords. Write or load your chord progression first. The bass takes its notes from it.
2. Pick the sound. A synth bass for busy, bouncy lines, or an 808 for long, booming notes in trap and hip-hop.
3. Find the root of each chord and play it one or two octaves below the chords.
4. Line the rhythm up with the kick. Start notes where the kick hits, or in the gaps between kicks for a bouncier feel.
5. Add movement with the fifth, the octave and a note that walks into the next chord.
6. Leave gaps. Shorten some notes, add rests, then play it with the whole beat and cut anything that crowds the kick or the vocal.

Which notes should a bass line play?

Start with the root of each chord, the note the chord is named after, then add its fifth and its octave, which almost never clash. Use the third, the seventh and notes one step from the next root only as short passing notes, and keep notes outside the chord off the strong beats.

Think of it as a ladder. Start on the bottom rung, the safest note, and climb only when the line needs more life. If words like root, scale and chord are new to you, our music theory guide for producers explains them in plain words.

Start with the root note

The root is the note a chord is named after. C is the root of C major, and A is the root of A minor. Play the root of each chord and the bass can’t clash with your harmony, because that note is already part of the chord. Most great bass lines spend most of their time on the root, and plenty never leave it. That’s not lazy. It’s the job.

Can’t tell which note is the root? Use your ears. In the course, the trick is to try notes one by one and listens for the one that sounds like home, the note where the chord feels settled. Max’s advice if you don’t hear it yet: “Just try to practice and try to even, like, hum what would be the home without hearing the bass note itself.”

In the bass’s Piano Roll, your chords show up as gray ghost notes (1). Drag one bass note up and down (2) and listen at each step. You can also click a key on the Piano Roll keyboard (3) to hear a note before you draw it.

Add the fifth and the octave

The next safest notes are the fifth and the octave. Both sit comfortably under almost any chord. The fifth is the fifth note of the scale counting from the root, seven half steps up if you count every key, black and white. Over A minor it’s E, and over C major it’s G. The octave is the root again, twelve half steps higher. Jumping between a root and its octave turns one note into a pattern, a sound you know from disco and house.

Use the third and the seventh as passing notes

The third tells the ear whether a chord is major or minor: C in A minor, E in C major. It’s a lovely, singing note in a bass line. Hold it on the first beat of a bar, though, and the chord sounds lighter and less settled, because the lowest note is no longer the root. Musicians call that an inversion. The seventh works the same way. Use both as notes you pass through, not notes you land on.

Walk into the next chord

An approach note sits one step above or below the next chord’s root, and you play it just before the chord changes. It makes the bass sound like it’s going somewhere. Use a note from your scale for a smooth walk, or a note one half step away for a jazzier, sneakier sound. One note is enough.

Pick the right octave

Keep the bass one or two octaves below your chords. Lower isn’t heavier. Past a point it just gets weak, and phone and laptop speakers can barely play it, which is why the course warns not to go too low. In FL Studio, select the notes and press Ctrl + Down to move them down an octave, the shortcut used in the course, or Ctrl + Up to move them back up.

How do you write a bass line to a chord progression?

Play the root of each chord when the chord changes, one or two octaves below the chords. Then fill the bar with that chord’s fifth or octave, and use a note one step from the next root to walk into it. Every note should come from the chord or your scale.

Here’s how a plain line grows into a moving one over a common four-chord loop in A minor: Am, F, C and G, one chord per bar.

1. Roots only: A, F, C, G, one long note per bar. Solid, but stiff.
2. Roots in rhythm: the same four notes, restarted on every kick hit, with a short gap after some of them.
3. Add fifths: halfway through each bar, jump to the fifth. A then E, F then C, C then G, G then D.
4. Walk to the next chord: make the last note of each bar one step away from the next root. G before the F, B before the C, A before the G, and B again before the loop starts over on A.

Each version keeps the line tied to the chords and adds a little more movement. Stop when it fits. A slow ballad might want version 1, and a funk groove might go well past version 4.

You can also do the opposite and hold one note while the chords change above it. Musicians call that a pedal note, and it makes a part sound darker and more tense. Our FL Studio bassline guide shows this trick, plus six more ways to make a line groove.

How do you make a bouncy bass line that locks with the kick?

Start bass notes on the kick hits so the two punch together, then add short notes in the gaps between kicks for bounce. Short notes with rests after them sound bouncy, and long ones sound heavy. Over a four-on-the-floor house kick, notes on the off-beats give the classic pumping bounce.

Notes decide whether the bass fits the chords. Rhythm decides whether it grooves. Let the kick drum guide you, because the kick and the bass share the bottom of the mix, and your ear hears them almost as one sound.

Start your notes on the kick

The simplest groove starts a bass note every time the kick hits, so the two punch together. It’s hard to get wrong. That’s how Max writes the 808 in the course: “follow the root progression, but follow also the rhythm of your kick drum.”

In the screenshot, the kick pattern sits in the top row of the Channel Rack (1). In the 808’s Piano Roll below, each note starts on one of those kick hits (2), and the 808’s own row in the Channel Rack shows the same notes lined up under the kicks (3).

Or play in the gaps between kicks

The opposite works just as well. Put the bass on the off-beats, the “and” when you count “1 and 2 and”. Over a kick on every beat, as in house music, the kick and the bass then take turns, which gives you that bouncing, pumping feel. The course points out that bass lines love the off-beats, especially over house drums.

Mix long and short notes

Note length is rhythm too. Short notes with gaps after them sound tight and bouncy, while long notes that run into each other sound smooth and heavy. Most good lines mix the two, for example a long note on beat one and a few short ones that push toward the next chord. Rests matter as much as notes. A gap gives the kick and the vocal room to be heard.

Repeat it, then change the last bar

A bass line should repeat, because repetition is what makes it catchy. Four identical bars in a row get flat, though. Mix Elite’s melody rule works for bass too: make something repetitive, repeat it in the first bars, and change it in the fourth. Keep bars one to three the same. Then add an octave jump, a quick fill or a walk-up in bar four.

Bass rhythms by genre

Every style has a habit you can start from:

• Pop and rock: steady eighth notes on the root, changing with the chords.
• House and disco: notes on the off-beats between a kick on every beat, often jumping between octaves.
• Trap and hip-hop: an 808 that starts with the kick and rings out, with an occasional slide between notes. The hi-hats carry the speed, so the 808 can stay sparse.
• Funk: short, syncopated sixteenth notes with lots of rests and a strong note on beat one, which funk players call “the one”.
• R&B and neo-soul: a relaxed line that fills the space between chord notes with passing notes and sits slightly behind the beat.
• Ballads: long notes on the root, often one per chord, so the vocal has all the room.

808 vs synth bass: how do you write each one?

Both play the bass line, but they behave differently, so you write them a little differently.

How to write an 808 bass line

An 808 is a bass played from a sample. The name comes from the Roland TR-808 drum machine, whose long, booming kick became the bass of trap and hip-hop. Producers tune the sample and play it in the Piano Roll like any instrument. Every note starts with a punch and then rings out, so as Max puts it, “An 808 usually behaves similar to a kick drum.” Some producers even drop the kick and let the 808 do both jobs.

• Use fewer, longer notes, and let each one ring until the next.
• Start the notes with the kick, as in the screenshot above, or let the 808 replace the kick.
• Slide into a few notes. A glide from one pitch to the next is a big part of the trap sound. In FL Studio, set the 808’s channel to Mono and turn on Porta.
• Keep it in key. An 808 has a clear pitch, so a wrong note sounds like a wrong note, not like a drum.

How to write a synth bass line

A synth bass is any bass sound from a synthesizer plugin, from short plucks to thick, moving Reese basses. It’s the busier cousin. Its notes stop when you release them, so it suits busier lines: off-beats, octave jumps and quick runs into the next chord. In the course, Max loads the free synth Vital, opens its preset browser and picks one of the bass presets (1). The macro knobs on the left (2) change the sound quickly, so you can try a few flavors without opening the deeper settings.

Can you use an 808 and a synth bass together?

Yes, as long as only one of them owns the lowest notes. When both play deep bass at the same time, they fight and the low end turns to mud. Let the 808 take the bottom and play the synth an octave higher, or switch between them from one section to the next. The mixing side, including sidechain, is in our guide on how to mix kick and 808.

Why does my 808 sound muddy or out of tune?

Usually because the 808 sample isn’t tuned to the note your sampler thinks it is, it sits too low, or its long tail overlaps the next note and the kick. Set the sample’s real root note, keep it one or two octaves below the chords, turn on Mono and duck it under the kick.

• The sample’s note is off. FL Studio’s Sampler plays a new sample at its original pitch on C5, its default root note. So if your 808 is really an F#, pressing C5 gives you an F#, and every root you draw comes out wrong. Find the sample’s real note by ear against a piano, or with a tuner plugin. Then right-click that key on the preview keyboard in the channel’s Miscellaneous settings to make it the root.
• It’s too low. Past a point, a deeper 808 doesn’t sound heavier. It sounds weak, as the course warns, and phones and laptops can barely play it. Keep it one or two octaves below the chords.
• The notes overlap. Two long 808 notes ringing at once smear into mud. Turn on Mono in the 808 channel’s settings so it plays one note at a time, or Cut itself, so each new note stops the last one.
• It fights the kick. In Mix Elite’s video on making the kick hit harder without ruining the 808, a kick and 808 left alone cause phasing and distortion in the low end. Set the 808 about 3 dB under the kick, then sidechain it so it ducks each time the kick hits.

For extra glue, that video routes the kick and the 808 to one group and adds a little saturation, so they sound like one sound. Our guide on how to mix kick and 808 covers the whole mixing side.

How to make a bass riff

A riff is a short bass phrase that’s catchy on its own, the bit people hum after the song ends. Keep it short. To write one, pick three to five notes from your scale. The minor pentatonic, a five-note scale that’s hard to get wrong, is a great place to start, and our music scales for beginners guide shows how to find it. Give the notes a one-bar rhythm with at least one gap and repeat it. When the chord changes, move the whole riff so it starts on the new root.

Then let the riff and the melody take turns. When the lead or the vocal is busy, keep the bass simple. When the lead rests, the bass can step forward and fill the gap. Musicians call that back-and-forth call and response, and it makes a riff feel like part of the song instead of a second melody fighting the first.

Common bass line mistakes

• Too low. It sounds weak, not heavy, and disappears on phone speakers.
• Too busy. A note on every step crowds the kick and the vocal.
• Wrong notes on strong beats. A note outside the chord, held on beat one, sounds like a mistake. On a weak beat, the same note sounds like a passing note.
• Fighting the kick. Bass notes that land just before or after a kick smear its punch. Line them up, or move them clearly into the gaps.
• Two basses in the same octave. An 808 and a synth bass both playing the deepest notes turn the low end to mud.
• Four identical bars forever. Repeat, but change something in the fourth bar.
• Fixing the tone before the notes. EQ can’t save a line that clashes. Get the notes right first, then shape the sound. Our bass tone guide covers the EQ side.

Start tonight with roots on the kick. Then add one idea per session: a fifth, an approach note, a gap, an octave jump. Within a week you’ll have a handful of moves you can reach for in every song. And if the chords themselves feel weak, fix those first with our guide on how to make chords in FL Studio, because a bass line can only be as good as the chords it follows.

Frequently asked questions