Effects

MI-Clouds

Mutable Instruments Clouds, compiled from the original C++ to WebAssembly - granular, time-stretch, looping delay, and spectral processing in one module.

Try one in your browser →

What is a MI-Clouds?

Mutable Instruments Clouds is the most influential granular processor ever made. Designed by Emilie Gillet and released in 2014, it took a high-end concept (granular synthesis as developed by Iannis Xenakis and Curtis Roads in academic computer music) and made it patchable, hands-on, and immediately musical. It became the secret weapon on countless ambient and experimental records, and even after Mutable discontinued the hardware in 2018, demand for it never stopped — which is why Émilie released the firmware openly so the design could live on past a single piece of hardware.

Granular synthesis works by chopping audio into very short overlapping windows called grains - typically 5-150 ms long - and replaying them. Each grain has its own position (where in the source it's read from), size (how long it is), pitch (how fast it's played back), and envelope (a window function so it fades in and out without clicking). Hundreds of grains per second, scattered with controlled randomness, blur into evolving textures - clouds of sound, hence the name.

Clouds packs four distinct processors into one panel by sharing the same input buffer and parameter set: Granular (overlapping grains, classic granular cloud), Stretch (WSOLA time-stretching that decouples pitch from speed), Looping Delay (with pitch shifting and filtering in the feedback path), and Spectral (a phase vocoder for FFT-domain frequency manipulation). Same knobs, four totally different transformations of the same source - and you can crossfade between them via the BLEND parameter.

The cultural footprint is enormous. Ambient, modular techno, sound design, drone, IDM — any genre that values evolving texture over fixed melody has been shaped by Clouds. The freeze button alone (which captures the input buffer and lets you scrub through it endlessly) defined a generation of ambient music. We carry the design forward into the browser.

Our MI-Clouds

This is the *actual* Mutable Instruments Clouds firmware - Emilie Gillet's original code, open-sourced under MIT, running natively in your browser. Bit-identical to the hardware module: same 4 modes, same Griesinger reverb, same feedback path with HP filter, same diffusion network, same quality settings, same parameter ranges. If you've used Clouds in a Eurorack rack, this behaves exactly the same way.

All 13 parameters are exposed: position, size, pitch, in-gain, density, texture, blend, spread, feedback, reverb, freeze, mode, quality. 8 CV inputs cover position, size, V/Oct (for pitch), blend, density, texture, plus FREEZE and TRIG gates. 18 HP panel with the original Mutable color scheme. The DSP overhead is comparable to one VCO at standard quality.

It's the lush, evolving, freeze-friendly ambient module that defined a decade of modular music - now in your browser with no cost, no hardware, no Eurorack power supply. Pair with Distant Horizons for shimmer-into-cloud washes, or feed it the output of a Plaits for granular synthesis on top of the most flexible voice in the rack.

In a patch

Clouds eats anything you feed it. Field recordings, synth pads, vocals, drums, the output of another module, the output of *itself* via feedback patching - it all becomes raw material. Place it after a VCA so each note gets a clean envelope into the buffer, and before reverb so the granular texture goes into the room rather than getting smeared by it.

The single best technique: hold a chord, hit FREEZE, then scrub POSITION slowly with an LFO (rate around 0.02-0.05 Hz). The frozen chord becomes an evolving pad that scans through itself, no two seconds the same. Modulate PITCH or SIZE for additional motion. Modulate DENSITY for sparse-to-dense gradients within the same frozen sound.

For sound design: feed Clouds a noise-source, set granular mode, low density, large size, and you have a wash of broken-glass texture that responds to every parameter change. Patch a slow random CV into POS for stochastic foraging through the buffer - a generative ambient patch that runs forever without repeating.

Inputs

In L (audio) — Left audio input. The signal that gets granulated, stretched, or processed. Mono input is fine - it will be spread to stereo.
In R (audio) — Right audio input. Patch both for stereo source material.
Freeze (gate) — Freeze gate input. When high, the input buffer stops recording and loops its current contents. Great for capturing a moment and exploring it.
Trig (gate) — Trigger input. In Granular mode, triggers a new grain. In other modes, behavior varies by algorithm.
Pos (cv) — CV control for the Position parameter. Modulate to scan through the recorded buffer.
Size (cv) — CV control for the Size parameter. Modulate for shifting grain sizes.
V/Oct (cv) — Pitch CV input (1V per octave). Shifts the pitch of the processed output without changing speed in Granular and Spectral modes.
Blend (cv) — CV control for the dry/wet Blend parameter.
Dens (cv) — CV control for the Density parameter. Modulate for evolving grain density textures.
Text (cv) — CV control for the Texture parameter.

Outputs

Out L (audio) — Left processed output. The granular/stretch/delay/spectral result mixed with the dry signal according to Blend.
Out R (audio) — Right processed output.

Controls

Position — Playback position in the recording buffer (0 to 1). At 0, grains play from the start of the buffer. At 1, from the end. Sweep this to scan through recorded audio.
Size — Grain size (0 to 1). Small values create short, crispy grains. Large values create long, smooth grains that blend into each other.
Pitch — Pitch shift in semitones (-24 to +24). Shifts the pitch up or down without changing the speed. At 0, the pitch is unchanged.
In Gain — Input gain (0 to 1). Controls how loud the signal going into the processor is. Turn up if your source is quiet.
Density — Grain density (0 to 1). How many grains overlap at once. Low = sparse, individual grains. High = dense, smooth cloud of sound.
Texture — Grain texture (0 to 1). Controls the windowing and overlap character of the grains. Low = smooth crossfades. High = harsh, glitchy edges.
Blend — Dry/wet mix (0 to 1). At 0, you hear only the dry input. At 1, only the processed granular output. 0.5 is an equal blend.
Spread — Stereo spread (0 to 1). How wide the grains are panned in the stereo field. At 0, mono. At 1, full stereo spread.
Feedback — Feedback amount (0 to 1). Routes the output back into the input for layered, evolving textures. Be careful at high values - it can build up.
Reverb — Built-in reverb amount (0 to 1). Adds space and diffusion to the output. Great for ambient washes.
Freeze — Freeze toggle. When active, the buffer stops recording and loops its current contents. The Position knob scrubs through the frozen audio.
Mode — Processing mode (0-3). 0 = Granular (overlapping grains), 1 = Stretch (WSOLA time-stretching), 2 = Looping Delay (pitch-shifting delay), 3 = Spectral (phase vocoder FFT processing).
Quality — Audio quality (0-3). Higher values use more CPU but produce cleaner sound. Lower values add lo-fi character.

Native port of

Direct compilation of Emilie Gillet's original Clouds firmware (open-sourced under MIT) from C++ to WebAssembly. All four parasite/factory modes - Granular, Stretch (WSOLA), Looping Delay, Spectral (phase vocoder) - are bit-identical to the hardware module.

Mutable Instruments Clouds

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