The MIDI groove generator

One bar of loaded dice

Phaseburn One’s sequencer does not play back a pattern you drew. It rolls dice you have weighted, and performs a fresh take every bar. This page builds one bass line from straight sixteenths into a living groove, one decision at a time — and every note it rolls also leaves the plug-in as MIDI, so the same dice can play any instrument you own.

Step one

Start with a line you already know

Sixteen sixteenth-note slots at full chance is an ordinary step sequencer: the same bar, forever.

On the Beats tab the grid reads BEAT PROBABILITY down its left edge, and every slot holds a chance from 0 to 127. Fill the sixteenth row and you have the bass line every step sequencer plays — tight, correct, and identical on every pass.

Nothing is wrong with it. It is just finished.

Beats · straight The Beats tab with the straight sixteenth-note row selected and all sixteen slots at full chance
The sixteenth row at 127 everywhere: a step sequencer.
Step two

Put dice on beat one

Three slots want the same moment. One weighted draw decides, and the winner rings for its whole length.

A moment’s budget is 127 points. Give the sixteenth on beat one 102 of them (80%), the quarter note 13 (10%) and the eighth 6 (5%), and the six points left over are a rest. Every bar, one draw picks a winner; it plays its full length and quiets every slot it overlaps.

Most bars open the way you drew them. Some hold the downbeat for a whole beat. One in twenty, the bar opens with a breath. That is not randomness bolted onto a pattern — it is the pattern.

Beats · beat one The Beats tab with the sixteenth on beat one at 80% and the quarter and eighth slots above it at 10% and 5%
Beat one, three ways: the quarter and eighth shapes hang over the sixteenth they compete with.
Step three

Draw the spine

A second map ranks every position in the bar. The rest of the instrument reads it.

Switch to the Strength tab and the grid reads BEAT STRENGTH. Paint beat one strongest, beat three next, two and four behind them, the offbeats faint. Fifteen STYLE templates start you off.

Six systems read the map: which note the pool picks, whether the octave jumps, where the length, position and velocity modifiers work, and a NOTE STRENGTH route that pushes one chosen parameter harder on the beats that matter. Loudness comes last, and only as far as the VELOCITY slider hands the map over.

Strength The Strength tab with a hand-drawn map: beat one strongest, beat three next, the offbeats faint
The Strength map. Nothing here makes a sound; everything else listens to it.
Step four

Tell each note where it is welcome

Every note in the pool carries a chance, a strength preference and a length preference.

The root is always there. Add the fifth and let it prefer strong beats. Add the root an octave down, prefer strong beats and long notes, and the bar’s held moments drop low the way a bass player’s would. Add the ninth at a quarter of the chance, prefer weak beats and short notes, and it mostly slips in between — a tenth as likely on a downbeat, a tenth as likely to ring long.

A note that prefers strong beats is boosted up to double on accents and cut to a tenth on ghosts: favored, never forced. Seventeen scales keep every choice inside the key.

Notes · pool The Notes tab with four pool notes lit and the NOTE module showing Chance, Strength and Length for the ninth
Four notes, four jobs. The ninth is set to weak beats and short notes.
Step five

Hang a fill off the last beat

A beat link forces its target whenever the source wins its draw. A target at zero exists only as a consequence.

Give the thirteenth sixteenth a 40% chance, zero the three after it, and chain them: 13 to 14, 14 to 15, 15 to 16. When beat 13 wins, the whole run plays; when it loses, none of it does. The fill arrives whole in some bars and never in pieces.

Links chain as far as you like — restraint is what keeps them groove-shaped — and pushing Length past full with Legato open turns the same chain into a slide.

Beats · links The Beats tab with a three-link chain from the thirteenth sixteenth through the last three slots of the bar
Beat 13 at 40%, then three forced follow-ups. One roll decides the whole fill.
Step six

Let the weak notes breathe

Humanize by length, not by smearing the beats that matter.

Shifting strong notes off the grid is how a machine imitates a player. A player does something else: the downbeat lands, and the notes in between vary in how long they hold. Aim a LENGTH modifier at Weak with a 40% probability and the ghosts clip short by up to the amount you set, differently every bar, while the accents stay put.

Then a touch of swing; then, if you still want it, a POSITION modifier for the weak notes only. Shifts happen after every decision is made, so they never change which slot won or which strength cell a note read.

Beats · feel The GLOBAL and LENGTH modules under the Beats grid with swing raised and one length modifier aimed at weak beats
One LENGTH modifier aimed at Weak, a little swing. The downbeat never moves.
Step seven

Play it from the keys

Three ways in, chosen in the keyboard strip under every page.

KEY TRIGGER is the default: hold a key and the phrase starts from step 1, transposed so your note is the root; lift it and it stops. Change key legato and it re-roots without restarting.

CHORD FOLLOW turns whatever you hold into the pool: each key a candidate, how hard you struck it that note’s chance — an arpeggio with a memory for your voicing rather than a pattern of its own. Switch Velocity Lock off first; it ships on.

FREE RUN hands the transport to your DAW and locks the bar to its bar lines.

Keyboard strip · MIDI Mode The MIDI Mode menu in the keyboard strip open on its three entries: Key Trigger, Chord Follow and Free Run
The same three modes in every format; the keyboard strip sits under every page.
Step eight

Send it somewhere else

Every note it rolls leaves the plug-in as MIDI, with the velocity the generator gave it.

Pull Phaseburn One’s own output down and it is a groove generator for anything on another track: your sampler, your drum machine, the synth you already love. VST3, CLAP and AU all send it.

It sends one note at a time and only what the sequencer plays — your own playing is not echoed through — and the standalone app, having no host to send to, carries clock and transport only. Host support for plug-in MIDI output varies, so check your host’s routing.

Phaseburn One rolls the bar
Your instrument plays the notes
Or skip the steps

Let GENERATE write the first draft

Sixteen groove families, rules you can read, no AI.

One press writes a working bar: anchors that always play, varied parts that change figure, fills that burst at the end — all from deterministic music-theory rules. No model, no training data, nothing learned from anyone else’s music. VARY mutates it without touching what works, and a ten-deep Undo walks it back.

Then everything above still applies: the dice, the Strength map, the pool, the links. GENERATE is the first draft. The groove is yours.

GENERATE The GENERATE module: scale and pattern on Auto, SPREAD, and the BEATS, NOTES and BOTH buttons
BEATS, NOTES or BOTH — a first draft, on rules you can read.
Go deeper

Read the chapters

Every claim on this page traces to the manual — the same manual that ships inside the plugin.

Open beta

Play it before it costs anything

Free and open — no card required. It’s free to use until October 15, 2026, then keeps working as a demo until you register a perpetual, DRM-free license (any time); ten beta users we pick get the full license free, and submitted presets can ship in the factory bank, credited to their authors.

Free €149 one-time at launch

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Perks and preset picks are at our discretion — the beta comes with no guarantees