You have a drum loop that knocks and a chord progression you like, and then you open a bass track and freeze. Play the root notes and it sounds like a demo. Play anything busier and it fights the kick, muddies the chords, or wanders off key. The bass is the part that is supposed to glue a track together, and when it is wrong everything above it feels unstable.
This guide is for producers who can build a beat and a progression but have never been taught what a bassline is actually doing. You will learn the two jobs every bassline has, how to build one up from root notes, how to make it lock with your kick instead of fighting it, and the handful of patterns that cover most of the music you listen to. Everything here is in plain note names, so you can follow along in any DAW.
What a Bassline Actually Does
A bassline has two jobs at once, and most weak basslines only do one of them.
The first job is harmony. The lowest note in a mix tells your ear what chord it is hearing. Play a C major chord with a C underneath and it sounds settled. Keep exactly the same chord but put an E in the bass and it becomes C/E, a first inversion, which sounds lighter and less finished. Put an A under it and your ear starts hearing A minor seven. The chords on top did not change; the bass changed what they mean. That is why a bassline that wanders into the wrong note does more damage than a wrong note anywhere else in the arrangement.
The second job is rhythm. The bass is the bridge between the drums and the harmony. It carries the pitch of the chords but moves with the timing of the drums, so it is the instrument that makes the groove feel like it belongs to the song. A bassline with the right notes and the wrong rhythm sounds like a keyboard player resting their left hand on the low keys. A bassline with the right rhythm and simple notes sounds like a record.
Hold onto both jobs as you work through the rest of this guide. Every decision below is really a question of which job a note is doing.
Start With Root Notes
The root is the note a chord is named after: C in C major, A in A minor, F in F major. Playing the root of each chord on the first beat of that chord is the foundation of nearly every bassline ever written, and it is where you should start every time, even if you end up somewhere much busier.
Take the most common progression in pop, I–V–vi–IV. In the key of C that is C, G, Am and F, so the root bassline is simply C, G, A, F, one note per chord. In A minor, the progression i–VI–III–VII is Am, F, C and G, and its roots are A, F, C, G. If you are not sure which notes belong to your key, the Key & Scale Reference shows every note in every major and minor key, and our guide to chord progressions that actually work explains where those numerals come from.
Play the root line against your drums before you add anything. It should already sound like a song. If it does not, the problem is usually the progression or the drums, and no amount of clever bass writing will fix it.
Before you write a single note, check which key your track is in. A bass note that is one half step off the key is the fastest way to make a whole mix sound amateur, and it is surprisingly easy to miss on laptop speakers because they barely reproduce the low end. Our guide to finding the key of a song covers the quick methods.
Add Movement With Fifths and Octaves
Once the roots work, the safest way to add movement is to use other notes from the same chord. Two of them are almost impossible to get wrong.
The octave is the root again, twelve half steps higher. Because it is the same note, it adds energy without adding any new harmony. Alternating root and octave in eighth notes gives you the bouncing line you hear all over disco and dance-pop, and it is the easiest way to make a static chord feel like it is moving.
The fifth is seven half steps above the root: G over a C chord, D over a G chord, E over an A minor chord. Every major and minor chord contains a perfect fifth, so root-then-fifth works under both, and it never clashes with what the chords are playing because it is already in them. Root on the first beat and fifth on the second is the classic two-step of country and a lot of early rock and roll. The one exception is a diminished chord, whose fifth is a half step lower than usual, so check that chord by ear.
The third is the note that decides whether a chord is major or minor, and it is the chord tone to use most carefully in the bass. It is not wrong; walking up root, third, fifth is a lovely melodic move. But a third sitting underneath the chord for a whole bar turns it into an inversion, and that is a different sound from the one you probably wanted.
| Pattern | Notes under a C chord | Feel |
|---|---|---|
| Roots | C, C | Solid, heavy, leaves room for everything else |
| Root and fifth | C, G | Bouncy, never clashes |
| Octaves | C, C (up an octave), C, C (up) | Driving, dance-floor energy |
| Chord arpeggio | C, E, G, E | Melodic, busier, good in sparse arrangements |
| Approach notes | C, then a note next to the next root | Smooth, pulls the ear into each change |
Lock the Bass to the Kick
This is the part most tutorials skip, and it is the part that separates a bassline that sounds produced from one that sounds added. The kick and the bass occupy the same stretch of the frequency range. A kick drum's weight usually sits somewhere between about 40 and 100 Hz, and the fundamentals of a bassline land right on top of it: the low E on a four-string bass is about 41 Hz, and the C above it is about 65 Hz. The Frequency Chart lists the exact figure for every note if you want to see where your line sits.
When two sounds share frequencies and hit at the same moment, they mask each other and you hear neither clearly. You have two good ways out of that, and they are opposites.
Lock with the kick. Put bass notes exactly where the kick hits, so the two land as one sound: the kick gives the attack, the bass gives the pitch and the sustain. This is the tight, punchy approach behind a lot of funk, house and modern pop. It only works if the two are balanced, which is what sidechain compression is for: the kick briefly ducks the bass so the transient comes through, then the bass swells back in behind it.
Answer the kick. Put bass notes in the gaps between kicks, so each fills a space the other leaves. It is the call-and-response feel of reggae, a lot of hip-hop, and anything with a syncopated, rolling low end. It needs less processing because the two rarely collide, and it makes a groove feel wider without making it louder.
LOCK OR ANSWER THE KICK
One bar of sixteenth notes. Numbers along the top are the four beats.
Whichever you choose, commit to it. The failure is a bass that lands a sixteenth after the kick, close enough to smear together and far enough apart to sound late. If your kick pattern is not settled yet, build it first in the Drum Machine, then write the bass against it; writing bass to a kick that keeps changing is how you end up with neither.
If your kick has a clear pitch, and most 808s and many electronic kicks do, tune it to the key of the track. A kick that sits on the root or the fifth of your key blends into the bassline instead of fighting it, and the difference is obvious the moment you hear the two together.
Approach Notes: Leading Into the Next Chord
Root notes tell the ear where each chord is. Approach notes tell it where the next one is going, and they are the single cheapest upgrade you can make to a plain bassline.
An approach note is a note played just before a chord change that sits right next to the next chord's root. The strongest version is chromatic: a half step below or above the target. Going from C to G, play F sharp on the last beat of the C bar and it slides straight into the G. Going from A down to F, play G flat just before the change and it drops into the F. Because the approach note is only there for a moment and resolves immediately, it does not need to belong to the key. Your ear hears it as tension that the next downbeat releases.
ROOT NOTES WITH APPROACH NOTES
Each column is one beat; each bar is four. Only the pitches the line uses are shown, and the brighter notes are the approach notes.
You can also approach by scale step, using the note from your key that sits next to the target: D up to E, or A down to G. It is gentler than the chromatic version and it suits pop and folk, where a half step outside the key can sound too jazzy. Try both on the same progression and keep whichever fits the song.
Use approach notes on some changes, not all of them. A line that approaches every single chord starts to sound like an exercise. One or two per four bars, usually into the change that matters most, such as the turn back to the top of the loop, is plenty.
Rhythm, Note Length and Space
Once the notes are right, almost everything that makes a bassline feel good is rhythm. Three controls do most of the work.
Note length. The same four notes played long and connected sound smooth and heavy; played short and detached they sound funky and tight. In a piano roll this is just the length of each note, and it is the most underused parameter in bass writing. If a line feels muddy, shorten the notes before you touch an EQ. The gap you create is where the kick and snare get heard.
Anticipation. Playing the next chord's root a sixteenth or an eighth early, before the downbeat, is called a push or an anticipation, and it makes a groove lean forward. It is all over funk, pop and R&B. Do it on one change and it feels urgent; do it on every change and the downbeat disappears.
Rests. A bassline is allowed to stop. Dropping out for half a bar before a chorus, or leaving the first beat of a bar empty, makes the next note hit twice as hard. The most memorable basslines tend to have fewer notes than you would guess.
When you draw these into your DAW, keep velocities fairly even. Bass needs consistency to hold a mix together; if you want dynamics, get them from note length and placement rather than from some notes being much louder than others. Our MIDI basics guide covers velocity, quantize and note length if any of that is new.
Choosing the Right Register
Where you play the line matters as much as what you play. Most basslines live between roughly E1 and C3, and the octave you choose changes how it sits in a mix.
Go too low and the line becomes a feeling rather than a note. Below about 40 Hz, laptops, phone speakers and most small desktop monitors reproduce very little, so on a phone a sub line that low can vanish completely. Your ear can still infer a pitch from its harmonics when the fundamental is missing, which is why producers add a little saturation or a higher layer to sub bass: it gives small speakers something to play. Go too high and the bass starts competing with the left hand of the keys and the low strings of the guitar, and the track loses its floor.
Whatever register you pick, keep the lowest part of the bass in mono. Stereo width in the sub range sounds impressive on headphones and collapses unpredictably on a club system or a mono phone speaker. Our guide to mixing low end goes deeper on the EQ, the sidechain and the checks that make a bassline translate.
Check your bassline on the worst speaker you own before you call it finished. If you cannot hear the notes change on a phone, the line is either too low or too pure, and a touch of harmonic content, or the same line doubled an octave up very quietly, usually fixes it.
Five Patterns Worth Stealing
Almost every bassline you know is a variation on a handful of shapes. Learn these five and you can write a convincing line in most genres.
Driving eighths. The root, repeated in straight eighth notes, changing with each chord. It is the engine of punk and a lot of rock, and it works because it leaves all the melody to everything else. It is also a good test: if a progression sounds great with driving eighths, it is a strong progression.
Root and fifth. Root on the beat, fifth on the next beat, back and forth. Country, polka and early rock and roll are built on it. It has bounce without busyness.
Octave bounce. Root, octave, root, octave in eighths. This is the classic disco and dance-pop shape, and it sounds huge because it covers two registers at once without adding a new pitch.
Walking line. One note on every beat, stepping through chord tones and approach notes toward the next chord. Jazz is the home of it, but a half-speed version works in soul, blues and gospel-flavored pop.
Long 808 notes. In trap and a lot of modern hip-hop, the bass is a tuned 808 playing long notes that follow the kick pattern, often gliding from one pitch to the next. The rhythm usually copies the kick exactly, which is the locked approach taken to its extreme, and the melody comes from choosing which root to glide to.
Common Bassline Mistakes
Too many notes. The bass is the foundation, and foundations are not where you show off. If the vocal or the lead is busy, the bass should be simple. Save the movement for the gaps.
Ignoring the kick. Writing the bass in solo and then hearing it against the drums for the first time is how you end up with a line that half-locks. Write it with the kick playing, always.
Out-of-key passing notes that do not resolve. A chromatic approach note works because it lands on a chord tone a moment later. Hang a note from outside the key on a downbeat, or hold it, and it just sounds wrong.
Every note the same length. Quantized, fully legato notes are the default in most piano rolls and the reason so many programmed basslines sound stiff. Vary length before you vary anything else.
Fighting the chords. If your keyboard part already plays a low root in the left hand, the bass and the keys are doubling each other in a crowded octave. Move the keys up, or thin out their low notes, so the bass has the bottom to itself.
Where to Take This Next
Take one progression you already have, loop it against your drums, and write four versions of the bassline: roots only, root and fifth, octaves, and roots with approach notes into the last change. Listen to all four against the kick. One of them will make the loop feel like a song, and it is often not the busiest one.
If you want to hear those patterns before you program them, the Chord Progression Builder now has a Bass Line mode: pick roots, root and fifth, octaves or approach notes, hear the line under your chords, and export both as MIDI, with the bass on its own track, ready for your own sound. It is one of the Player tools. For the chords themselves, the Piano Chord Charts show every voicing on the keys, and the Circle of Fifths shows which chords belong together in any key. And if the beat under all of this still needs work, how to make a beat from scratch is the place to start.
Frequently Asked Questions
What notes should a bassline play?
Start with the root of each chord on the first beat of that chord: C under a C chord, A under an A minor chord. Once that works against the drums, add the fifth and the octave, which are already in the chord and cannot clash. Approach notes a half step from the next root are the next step up.
Should the bass play at the same time as the kick?
It can either lock with the kick, landing exactly where it hits, or answer it, playing in the gaps between kicks. Both work. What does not work is landing just after the kick, close enough to smear together and far enough apart to sound late. If you lock, sidechain compression keeps the kick audible.
How low should a bassline go?
Most basslines sit between roughly E1 and C3. The low E on a four-string bass is about 41 Hz. Below about 40 Hz, laptops and phone speakers reproduce very little, so a line down there can disappear on the devices most people listen on. Adding a little saturation or a quiet octave-up layer helps small speakers carry it.
Does the bassline have to stay in the key?
The notes that land on beats and hold for a while should. Short passing notes outside the key are fine, and chromatic approach notes are a staple, because they resolve to a chord tone a moment later. A note from outside the key held on a downbeat is what sounds wrong.
Why does my bassline sound muddy?
Usually because the notes are too long, too low, or collide with the kick. Shorten the notes first so there are gaps for the kick and snare, then decide whether the bass locks with the kick or answers it, and keep the lowest octave in mono. EQ comes after those three, not before.