Ableton Topline

Ableton Topline

Generate a singable melody / topline over an existing chord progression, written as a lead MIDI track. Good toplines are mostly chord tones on strong beats, with stepwise motion and tasteful rests between phrases.

When to use

Triggers: "write a melody/topline/hook over these chords", "add a lead". For an existing theme's melody use ableton-genre-cover; for free natural-language generation use ableton-describe-to-midi.

Process

1. Use ableton-live-runner for build/run/kill + scaffold.
2. Get the harmony + key — read the chord clip (clip.notes) or text; read song.rootNote /

song.scaleIntervals to stay in scale.

1. Build the melody with these principles:

• Anchor on chord tones on beats 1 & 3; use scale tones / passing tones on weak beats.
• Stepwise motion mostly; reserve leaps for emphasis (and resolve them by step).
• Phrase with rests — 2- or 4-bar phrases that breathe; call-and-response.
• Motif + variation — state a short motif, then repeat it transposed/rhythmically varied.
• Contour & climax — build to one high note, then resolve down to a stable tone.
• Register — vocal/lead range ~MIDI 60–84.

1. Write the track (["Wavetable","Operator","Drift"] + [["Echo"],["Reverb"]] for an airy

lead) and humanize velocities with vary.

Code pattern (motif + transposed answer)

const MOTIF = [ {t:0,p:0,d:1}, {t:1,p:2,d:1}, {t:2,p:4,d:1.5} ]; // scale-degree offsets; d:1.5 = a breath
function deg(rootMidi, scale, n) {                 // n-th scale degree (with octave wrap)
  return rootMidi + scale[((n % scale.length) + scale.length) % scale.length] + 12 * Math.floor(n / scale.length);
}
function writeTopline(notes, rootMidi, scale, phrases, bpb = 4) {  // phrases = [{bar, shift}]
  for (const ph of phrases)
    for (const e of MOTIF)
      notes.push({ pitch: deg(rootMidi, scale, e.p + ph.shift), startTime: ph.bar*bpb + e.t, duration: e.d, velocity: vary(96) });
}

Limits

• Avoid landing on the avoid-note (e.g. the 4th over a major chord) on strong beats.
• Leave space — a sparse, memorable topline beats a busy one.

See ableton-reharmonize, ableton-theory-coach, ableton-humanize.

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.