The Drone Machine

Manual for version 1.1.2. Audio Unit, VST3 and standalone for macOS. By Mouritz.

What it is

The Drone Machine is an instrument that is always on. Load it, and it sounds. You set a root note, shape one overtone spectrum for the whole instrument, and it breathes and drifts on its own, on cycles that never line up, so it never repeats.

Six layers of oscillators tune themselves to each other in equal temperament, just intonation, Pythagorean or meantone. A Harmonic Field sculpts one spectrum shared by the additive layers and the resonators. A texture section adds noise, eight tuned resonators, a slow pluck and a bow. The effects chain runs drive, ensemble, three delays in series, a large reverb with shimmer, bloom, freeze and hold, an EQ and a limiter. Three LFOs, two drift sources, a looping envelope, an envelope follower, four macros and a slow swell feed a 16-slot modulation matrix, and Evolve morphs the sound over minutes and hours while Choreography brings layers in and out.

Quick start

1. Install the Audio Unit, the VST3 or the standalone app from the installer, then open your host.
2. Put The Drone Machine on an instrument (MIDI) track. It sounds as soon as it loads. In the standalone app, choose your output in Options first.
3. Press a MIDI note: the root moves there and the pitch glides. Or pick the root in the top bar.
4. Browse presets with the arrows next to the preset name, or click the name to search.
5. Click Simple in the top bar if you want ten controls instead of two hundred.
6. Drone fades the whole instrument out and back in. Gate makes it sound only while a MIDI note is held.
7. Panic silences everything and clears every tail at once.

The reverb and delay tails keep ringing after Drone goes off, as a real room would.

The window

The window scales from 75 % to 300 %: click the percentage at the right end of the top bar for a list of sizes and a "Fit to screen" option, or drag the corner. The size is remembered with the plug-in state. On first open the window sizes itself to the display. The layout is the same at every size.

• Top bar: preset navigation and A/B comparison, favourite star, Save, Randomise with its amount slider, the Simple toggle, Root, Tuning, Master, Glide, A4 reference, Drone, Gate, Freeze, Hold and Panic. The CPU and phase-correlation meters sit under the title. Click the title for the About panel, the version and this manual.
• Layer strips: three on each side, one per layer.
• Harmonic Field: the spectrum in the middle, with its shape buttons and macros.
• Macros: the four big knobs under the field. Double-click a name to rename it.
• Tabs along the bottom: Mod, Matrix, FX, Space, Texture, Evolve, Grain, Loop and Scenes. Space holds both reverbs.

Every knob shows its real, modulated position as a second mark, so you always see what the instrument is doing, not just what you set. Right-click any control to MIDI-learn it. Double-click a knob to return it to its default.

Simple view

Simple in the top bar hides the layers, effects and modulation and leaves ten controls on one page: Root, Tuning, Character, Drone, the four macros, Reverb Mix, Reverb Decay and Master. The choice is saved with the plug-in state, so a project reopens the way you left it.

The same ten controls come first in the parameter list your host shows for the plug-in, so a host's own generic device panel, such as Bitwig's or Live's, doubles as a simple view without opening the window at all.

Character gives every sounding layer the same source in one move: Saw, Square, Triangle, Sine, Additive, or one of the eight wavetables (Warm, Organ, Reed, Hollow, Choir, Glass, Bell, Pulse Sweep). Intervals, filters, levels and effects stay as the preset left them. The box shows the current source when all layers agree and "As preset" when they differ. Muted layers are left alone.

Every factory preset wires its four macros the same way, so the Simple page behaves consistently from preset to preset:

The macros live in matrix slots 5 to 16, so slots 1 to 4 stay free for each preset's own routings. Rename or rewire them on the Matrix tab as you would any other slot.

Root, tuning and glide

• Root is the note the whole instrument is built on, from C0 to C7. A MIDI note-on moves it. Whichever moved last, the parameter or MIDI, wins.
• Glide (0 to 20 s) is the time the pitch takes to reach a new root. It is linear in pitch, so a long glide sweeps evenly.
• Tuning sets how the layer intervals are derived: Equal Temperament, Just Intonation (5-limit), Just Intonation (7-limit), Pythagorean or Meantone. A fifth in just intonation is a pure 3:2, so layers lock together without beating. Change it while the drone plays to hear the difference.
• A4 sets the reference pitch, 415 to 466 Hz.

Layers

Each of the six layers is one voice with its own source, unison, filter and output. The strips show the most useful controls; the rest are on the layer's parameters in the host and in the parameter reference at the end of this manual.

• Role sets a sensible starting point for the layer's place in the mix: Foundation (an octave down, band-limited low), Mid (unison, wide), Detail (an octave up, bright) or Noise Bed (very detuned, high). Custom means you set everything yourself. Choosing a role rewrites the interval, band limits, cutoff, unison and level, nothing else.
• Interval from the root: Unison, Octave -2 to +2, Fifth, Fourth, Major 3rd, Minor 3rd, Minor 7th, or Custom with a free ratio from 0.25 to 8.
• Source: Saw, Square (with pulse width), Sine, Triangle, Additive (drawn in the Harmonic Field), Wavetable with a position control, Granular (see the Granular layer section) or Feedback (see the Feedback voice section). The eight wavetables are original: Warm, Organ, Reed, Hollow, Choir, Glass, Bell and Pulse Sweep.
• Unison: 1 to 7 voices, detune in cents, stereo spread.
• Filter: low-pass, band-pass, high-pass or notch, with cutoff, resonance and key tracking. A separate band limit (low cut and high cut) keeps a layer in its register whatever the filter does.
• Drift: a slow random walk of the pitch, in cents. A few cents is analog warmth, twenty is seasick.
• Drive: a per-layer soft-to-hard clipper with automatic gain compensation, oversampled so it stays clean at the top.
• FM: a light frequency modulation from a ratio-locked sine (depth, ratio 1 to 8) with its own slow LFO.
• Level, Pan, Mute and Solo. A muted layer costs no CPU.

Granular layer

Set a layer's source to Granular and it plays a cloud of overlapping grains taken from a sample instead of an oscillator. The grains are repitched to the layer's note through the tuning engine, so a granular layer sits in the chord like any other. Its controls are on the Grain tab.

• Sample: one of the built-in sources, all original: Piano Chord, Bowed Cymbal, Singing Bowl, Voice Ah, Wind and Bell, or one of six user slots. Drop an audio file on a layer strip (WAV, AIFF, FLAC, MP3, M4A, up to 30 s) to load it into that layer's slot: the layer switches to Granular, the file is mixed to mono, resampled, normalised and its root pitch detected so grains follow the drone's root. The sample is stored inside the plug-in state, so a project or a user preset carries it with it. Loading a factory preset keeps your samples.
• Mode: Freeze keeps the playhead at Position; Scan moves it slowly back and forth through the whole sample over Scan Time.
• Position: where in the sample the grains are taken from, 0 is the start.
• Grain Size: 20 ms to 2 s. Long grains keep the character of the source; short ones turn it into a texture.
• Density: one knob from sparse and airy, a few long grains with gaps between them, to dense and smeared, dozens overlapping. The level stays about the same across the range.
• Jitter: how far each grain may start from the position. A little jitter keeps the cloud from sounding like a loop.
• Spread: how widely the grains are panned.
• Pitch: an offset in semitones on top of the layer's interval. Minus 12 for a darker, slower version of the source, plus 12 or 24 for shimmer.
• Window: the shape of each grain's envelope: Hann, Gaussian or Triangle.
• Reverse: the share of grains that play backwards. Any value above zero softens attacks and makes the cloud less recognisable.
• FM and FM Rate: a slow or fast wobble of the grains' playback speed. Slow rates give vibrato and chorus, fast ones add sidebands.

Grains never cross the end of the sample and every grain fades in and out, so there are no clicks at any density or size. The filter, band limit, drive, drift, level and pan of the layer work exactly as for an oscillator. Switching a layer between an oscillator and Granular crossfades. If the detected root is wrong for an unpitched or chord-like file, use Pitch to tune it; unpitched files are treated as A3.

Feedback voice

Set a layer's source to Feedback and it becomes a "no-input" instrument: a short delay tuned to the layer's note, a resonant peak, a saturator and a feedback path, with nothing going in but a whisper of noise. Turn Feedback up past the point where the loop gains more than it loses and it starts to sing on its own, on the note the tuning engine gives it. The controls are on the layer strip.

• Feedback: how much of the loop comes back around. Below about 0.4 the loop stays silent; above it, it builds up over a second or two.
• Tone: where the resonant peak sits, from the fundamental up to four octaves above it. This picks which harmonic the loop settles on.
• Loop Drv: saturation inside the loop. More drive gives more harmonics and a quicker, harder onset.
• Wander: a slow, random movement of the peak and a few cents of pitch, so the voice never sits still.
• Loop Tuning: the delay at the note, an octave or two octaves below it, or a fifth below.

Safety is built in: a soft clip and a DC blocker inside the loop, a limiter at the layer's output, a slow ramp when Feedback goes up, a runaway guard that pulls the loop down if it ever grows too hot, and Panic clears every feedback loop. The layer's filter, drive, level and pan apply as usual, and switching between sources crossfades.

Harmonic Field

The Harmonic Field is one spectrum for the whole instrument. Draw the level of each of the 32 partials with the mouse, or start from a shape: Saw, Square, Triangle, Organ or Sine. Every layer set to Additive plays this spectrum, and the resonators in the texture section follow it, so changing the field changes the character of everything at once.

• Tilt darkens or brightens the whole series.
• Odd / Even favours odd partials (hollow, clarinet-like) or even ones (fuller, octave-rich).
• Formant and Formant Amount sweep a resonant peak across the series, the way a vowel moves. Modulate Formant slowly for choir-like movement.

The teal trace behind the bars is the live spectrum of the output.

Sub layer

A clean sine or triangle one or two octaves below the root, added after the effects so it stays dry, centred and solid under everything. It is on the Texture tab.

Texture

The texture section sits between the layers and the effects.

• Noise: white, pink, brown or air, with a tilt filter, a level into the mix and a separate send into the resonators.
• Resonators: eight tuned resonators on the harmonic series of the root, with their gains following the Harmonic Field. Level, Decay (0.2 to 30 s), Damping, Spread, and how much of the layers and of the aux input they receive. This is the sympathetic-string, singing-bowl part of the sound.
• Pluck: a slow exciter that strikes the resonators in a pattern: Tanpura, Even, Heartbeat or Wander, with rate and brightness.
• Bow: a sustained exciter with pressure.
• Scrape: friction in strokes, a band of noise that comes and goes. Strokes sets how often, Tone where the band sits.
• Roll: stones rolling in the bowl, an irregular stream of micro-impulses whose density you set, swelling and fading as they circle at the Roll Circle period.

Effects

The chain is fixed in this order: Drive, Ensemble, Delay Stack, Reverb, Convolution, Damage, EQ, Looper, then the output stage. The reverbs are on the Space tab, the rest on the FX tab. Every send has a low-cut, so only the upper part of the sound enters the ensemble, the delays and the reverb and the low end stays dry and clean.

• Drive: tape, tube or fold, with amount and mix. Oversampled.
• Ensemble: a wide chorus with mix, depth and rate.
• Delay Stack: three delays in series, free-running rather than tempo-locked. Each has its time, feedback, tone and level. The third one plays backwards. Feedback is soft-clipped inside the loop, so "just below oscillation" is a safe place to sit.
• Reverb: a large feedback-delay-network reverb. Mix, Decay (0.1 to 60 s), Pre-delay, Size, Damping and Modulation. 100 % Wet removes the dry path. Shimmer adds an octave-up tail, Bloom feeds the tail back into itself so it swells and reveals overtones, Duck lowers the reverb while the dry signal is present so the source stays clear. Pre and post low and high shelves and a notch shape the tail.
• Freeze holds the reverb tail forever. Hold captures the sound and lets it decay over Hold Decay (1 to 120 s), so you can change everything else and play over it. Both are on MIDI CC 20 and 21.
• Damage: light wear for a clean pad. Cuts are tiny random dropouts, Dust is crackle, Wow & Flutter a tape-style pitch wobble, Degrade a touch of bit and rate reduction. All are probability-driven and never rhythmic; Mix sets how much of the worn signal you hear, and a little goes a long way. It is off by default.
• EQ: low shelf, two parametric mids, high shelf, and a Presence lift.
• Mix Hygiene: a low cut (12 or 24 dB per octave), Mono Below which sums the bass to mono under a crossover frequency, stereo Width, and a Mono Check button. The phase-correlation meter in the top bar shows how mono-compatible the output is.
• Output: a sub floor high-pass, and a look-ahead limiter with ceiling and release. The limiter is the last stage and holds a hard ceiling.

Convolution

A second reverb, on the Space tab next to the algorithmic one, built on measured-style impulse responses rather than a feedback network. It sits after the algorithmic reverb in the chain, so the two can be layered.

• On switches it in. Off costs nothing.
• Space: six built-in spaces, all synthesised for this plug-in: Hall, Chamber, Plate, Cathedral, Tunnel and Reverse. Or User, your own impulse response: drop a WAV, AIFF or FLAC file (mono or stereo, up to 20 s) on the Impulse Response box. It is stored inside the plug-in state, so projects and user presets carry it, and loading a factory preset keeps it.
• Mix balances dry and convolved sound.
• Stretch plays the impulse response slower and lower, 1 to 4 times, the old trick of re-recording a room at speed and slowing it down. The tail gets longer and darker. Stretched responses are capped at 20 s.
• Pre-delay holds the reverb back by up to 200 ms so the dry sound stays in front.
• Send Low-Cut keeps the low end out of the convolution, as with every other effect.

The convolution adds no latency. Changing the space or the stretch rebuilds the response in the background; the sound switches when it is ready.

Looper

The looper is the last effect in the chain, a tape loop in the spirit of Frippertronics. Its controls are on the Loop tab. It records what you hear, or the aux input, into a loop of 1 to 60 seconds and plays it back on top of the live sound, so a drone can pile up layer on layer while you change everything else.

• On switches the looper into the chain. Off costs nothing and leaves the signal untouched; the loop's content is kept.
• Record overdubs: while it is on, the live signal is added to the loop on every pass. Turn it off and the loop repeats unchanged.
• Feedback is how much of the previous pass survives each time you overdub. At 1 nothing fades and the loop fills up; a soft clip inside the loop keeps it from running away. At 0.5 each pass halves what came before.
• Length of the loop. Changing it while playing makes a short dip while the loop re-wraps.
• Speed plays the loop from a quarter speed to four times, two octaves either way, while new material is still recorded at normal speed. Reverse plays it backwards. Both are tape-style: they change the playback head, not the loop itself.
• Mix balances live sound and loop. Source chooses between the mix and the aux input.
• Clear wipes the loop with a short fade. Panic clears it too.

MIDI CC 24 toggles Record and CC 25 clears, so a foot controller can run the loop.

Modulation

The Mod tab holds the sources, the Matrix tab routes them.

• LFO 1 to 3: rate from 0.005 to 20 Hz, six shapes (sine, triangle, saw, square, sample and hold, smooth random), optional tempo sync with a division. They are unsynced by default and their default rates are deliberately unrelated.
• Drift 1 and 2: smooth random sources with a timescale from 1 s to 10 min.
• Loop Envelope: attack and decay up to 30 s each, looping.
• Env Follower: follows the output level.
• Macro 1 to 4: the four big knobs. Name them on the macro bar.
• Swell: a slow breathing of level and brightness, with depth and period (5 s to 5 min).
• Incommensurate: one button that re-rolls every LFO, drift and envelope cycle so that no two are a simple ratio of each other. The combined motion then takes a very long time to repeat.

Matrix: 16 slots, each with a source, a destination, an amount from -100 % to +100 % and a polarity. Any continuous parameter can be a destination. Bipolar sources swing both ways around the knob's position; unipolar ones only add.

Play: Drone on/off with its fade-in and fade-out times, and MIDI Gate.

Evolve and Choreography

Evolve is the machine in The Drone Machine. Turn it on, set a timescale from one minute to one hour and an amount, and eight slots each walk one parameter between a low and a high limit on their own unrelated cycles. Set the limits to the range you would be happy to hear and walk away.

Choreography brings the layers themselves in and out: each layer fades in and out on its own slow cycle (fade times from 5 s to 5 min), dwells for a while, and a minimum number of layers always sounds. Merge biases them to overlap before dissolving, so the sound grows into one body and then thins out again.

Scenes

A scene is a snapshot of every control: layers, field, texture, effects, modulation, all of it. The Scenes tab has eight slots, A to H. Press Store and then a letter (or shift-click the letter) to keep the current sound there; click a letter to go there. Going there is a morph, not a jump: every continuous control glides from where it is to the stored value over the Morph Time (1 s to 5 min), and switches flip halfway. The bar under the letters shows the morph, and you can keep playing while it runs; the next recall starts from wherever the sound is at that moment.

Scenes are saved with the project and with user presets. Loading a factory preset clears them. Momentary and transport controls (Panic, Looper Record and Clear) are never part of a scene, nor is the Morph Time itself. < and > step through the stored scenes in order, and so do MIDI CC 26 and CC 27, so a foot controller can walk a set from one scene to the next. Right-click a letter to store or clear it.

Presets

Click the preset name to open the browser: search by name, filter by category, show favourites only. The arrows step through the list. The star marks a favourite. Save stores a user preset with a name and category. Factory presets are built in and cannot be overwritten.

User presets are files in ~/Library/Application Support/Mouritz/The Drone Machine/Presets. Each is a small XML file, so you can back them up or share them.

A / B keeps two sounds and lets you flip between them; A>B copies the current one to the other slot. Randomise moves the sound somewhere new within safe limits: the slider sets how far. It never mutes everything and never touches the macro wiring.

The 37 factory presets are grouped as Tanpura & Shruti, Organ, Abyss, Choir, Glacier, Meditation, Industrial, Cosmic and Utility, plus Init. All of them are trimmed to the same loudness, and all of them answer to the four macros as described under Simple view.

MIDI

• A note-on sets the root. With Gate on, the drone sounds while any note is held.
• CC 20 Freeze, CC 21 Hold, CC 22 Panic, CC 23 Drone on/off, CC 24 Looper Record, CC 25 Looper Clear, CC 26 Next Scene, CC 27 Previous Scene.
• MIDI learn: right-click any control and move a controller. The mapping uses soft takeover, so a controller that is far from the knob's position has to pass through it before it takes over; nothing jumps. Mappings are saved with the project, not with presets.
• Aux input: the plug-in has a second input bus. Enable it in your host to feed any audio into the resonators and the reverb.

Latency and CPU

The layer drives, the master drive and the limiter's look-ahead add a fixed delay, about 2 ms at 48 kHz, which is reported to the host so your other tracks stay in time. The plug-in supports 44.1 to 192 kHz. Muted layers and unused effects cost nothing; a full preset with six layers, resonators and reverb uses a few percent of one core.

Troubleshooting

• The plug-in does not appear: quit and reopen the host. Logic may need the Audio Unit cache reset: killall -9 AudioComponentRegistrar in Terminal, or a restart. In Ableton Live, check that VST3 and Audio Units are enabled in Settings, Plug-ins, then Rescan.
• It is silent: check Drone in the top bar, Gate (it needs a held note), and the Master knob. Panic mutes until Drone is on again.
• It sounds different after an update: hosts keep the old plug-in code loaded until they are restarted.
• Where are my presets? ~/Library/Application Support/Mouritz/The Drone Machine.

Trial and licence

The Drone Machine runs as a free trial for seven days from the first time it is opened on your Mac. The trial covers every feature, with one reminder: roughly every twenty seconds a voice says "You are using the trial version of The Drone Machine" in place of the sound. When the trial ends the plug-in keeps its window and settings but mutes its output until a licence key is entered. A key removes the dropouts at once.

• Buy a key at mouritz.no. It is issued to your name and email and arrives as a short text; paste it into the licence window, or drop the key file on it. The window opens by itself when the trial is over, and from the About panel (click the title) at any time.
• Activating takes one short connection to mouritz.no, which ties the key to your Mac. After that the key is checked offline: the plug-in never connects again, and the key keeps working without us.
• One key is active on two computers at a time. To move it, click the title, choose Licence key and press Deactivate on the Mac you are leaving, then activate on the new one. If a Mac is gone for good, write to us and we free its place. The activation is stored next to your presets, in ~/Library/Application Support/Mouritz/The Drone Machine/licence.key, and only works on the Mac it was issued to.

Licence

The Drone Machine is proprietary software, licensed under the end user licence agreement shown by the installer and at mouritz.no. Copyright (C) 2026 KomoHouse AS. All rights reserved. It is built with JUCE (Raw Material Software Limited, under the JUCE licence) and the Steinberg VST3 SDK (under the Steinberg VST3 Plug-in SDK Licensing Agreement). VST is a trademark of Steinberg Media Technologies GmbH. The pink-noise filter is Paul Kellet's well-known economy filter. Everything else, including every preset, wavetable, sample and space, is original.

Parameter reference

Every parameter the plug-in exposes to the host, by section. The id is what a preset file and the MIDI map store. The six layers share one list of parameters (ids l1_ to l6_), as do the 16 matrix slots (mm1_ to mm16_) and the 8 Evolve slots (evo1_ to evo8_). A parameter marked mod can be a modulation destination.

Global

Harmonic Field

Sub

Layers 1 to 6

Texture

Drive

Ensemble

Delay

Reverb

EQ

Output

Mix Hygiene

Granular (layers 1 to 6)

Looper

Convolution

Exciters

Damage

Feedback Voice (layers 1 to 6)

Modulation

Mod Matrix

Evolve

Play

Scenes