Ableton Bassline

Ableton Bassline

Generate an idiomatic bassline that follows a chord progression, written as a MIDI track in the Live Set. The bassline is the soul of most genres — its rhythm and space matter as much as its notes.

When to use

Triggers: "write a bassline", "bass from these chords", "[genre] bass". For full arrangements use ableton-genre-cover; for the chords themselves use ableton-reharmonize.

Process

1. Use ableton-live-runner for build/run/kill + scaffold.
2. Get the progression — from a clip (read clip.notes, take the lowest/root per bar) or from

text. Read the key (song.rootNote) and song.scaleIntervals to keep passing tones diatonic.

1. Pick the style feel (the defining choice). Apply its rhythm template, transposing the root per

chord. Use low register (root around MIDI 28–40) and a fallback instrument list ending in Drift (["Operator","Drift"] — note "Bass" does not insert).

1. Add motion tastefully — passing tones into the next root, octave pops, ghost notes. Keep the

genre's characteristic rests.

1. Write the track and shape tone with ableton-tone-recipes/ableton-fx-chain (Auto Filter to

round, Compressor + Saturator to make it audible on small speakers).

Style rhythm templates (relative beats within a bar)

| Style | Pattern (R = root, 5 = fifth, 8 = octave, · = rest) | |---|---| | Reggae one-drop | R · · 5 R · 8 · (leave beats 2 & 4 open — the breath) | | Rocksteady/ska | R · R(&) 5(&) R · 8(&) · (bouncy, syncopated) | | House | steady 8ths on root with off-beat octaves | | Funk | syncopated 16ths, root + ♭7 + octave, ghost notes | | Lofi | R(1, long) · · · R(2.5) · · · (deep, sparse) |

Code pattern (generic bouncy example — adapt the rhythm to a table row above)

const ROOTS = [/* MIDI root per bar, e.g. */ 33, 33, 32, 37]; // octave pops (r+12) intentionally
                                                              // exit the bass register
function writeBass(notes, bars, bpb = 4) {
  for (let bar = 0; bar < bars; bar++) {
    const r = ROOTS[bar % ROOTS.length], b = bar * bpb;
    notes.push({ pitch: r,    startTime: b + 0,   duration: 0.45, velocity: vary(108, 3) });
    notes.push({ pitch: r,    startTime: b + 1.5, duration: 0.25, velocity: vary(90) });
    notes.push({ pitch: r,    startTime: b + 3,   duration: 0.40, velocity: vary(102) });
    notes.push({ pitch: r+12, startTime: b + 3.5, duration: 0.25, velocity: vary(84) }); // octave lift
  }
}

Limits

• "Bass" device fails to insert; use Operator/Drift + Auto Filter to round the tone.
• Keep it deep but out of the kick's way — leave space (sparse beats out-groove busy ones).

See ableton-reharmonize, ableton-tone-recipes, ableton-drum-groove.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Korben00
• Source: Korben00/ableton-producer-skills
• License: MIT

Install and usage instructions live in the source repository linked above.