Mutable Instruments Clouds User Manual

Mutable Instruments | Clouds

Clouds is a granular audio processor. It creates textures and soundscapes by combining multiple
overlapping, delayed, transposed and enveloped segments of sound taken from an audio recording buffer.

Clouds differs from other granular Eurorack modules in that it focuses on the real-time processing of audio
sources from your modular system itself, rather than the playback of pre-recorded samples from a storage
device. It rewards the freezing, fragmentation and dissolution of the unexpected instant, rather than the
careful planning of what might very well not come.

Clouds is designed for Eurorack synthesizer systems and occupies 18 HP of space. It requires a -12V /
+12V supply (2x5 pin connector), drawing 10mA from the -12V rail and 120mA from the +12V rail. The red
stripe of the ribbon cable must be oriented on the same side as the “Red stripe” marking on the printed
circuit board.

This device complies with part 15 of the FCC Rules. Operation is subject to the following
two conditions: (1) This device may not cause harmful interference, and (2) this device must
accept any interference received, including interference that may cause undesired
operation.

This device meets the requirements of the following standards: EN55032, EN55103-2,
EN61000-3-2, EN61000-3-3, EN62311.

Clouds continuously records the incoming audio into a short amount of sample memory. While recording
time can reach up to 8s by reducing the audio quality setting, you ought to feel very guilty every time you
think of this as “tape” - think of it as a space, a room. Using this recorded audio data, the module
synthesizes a sonic texture by playing back short (overlapping) segments of audio (also known as
“grains”) extracted from it.

Clouds allows you to control:

From which part of the buffer the grains are taken.
How long the grains are.
At which speed/pitch the grains are replayed.
How much overlap there is between the grains (density).

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Mutable Instruments | Clouds

Whether the distribution of grains in time is constant or random.
Which envelope curve is applied to the grains - giving the impression of a “rough” or “smooth” texture. In

addition, to create textures with a “blurry” feel, a diffuser (network of all-pass filters - like a reverb without tail)
can be applied.

The module plays grains continuously, at a rate determined by the DENSITY and SIZE settings. A trigger
input is also present, to explicitly instruct the module to start the playback of a new grain. The maximum
number of concurrent grains is quite large - between 40 and 60. This specificity brings Clouds closer to the
roots of granular synthesis, and allows the synthesis of varied textures even from basic waveforms ­there’s indeed many more dimensions to granular synthesis than keeping a playback pointer moving
through a SD-card sample!

It is possible, at any time, to FREEZE the audio buffer from which the grains are taken - In this case, the
incoming audio is no longer recorded. Somehow, Clouds is the exact opposite of a sampler: by default, the
module always samples the audio it receives, except when it is in the frozen state.

A. FREEZE button. This latching button stops the recording of incoming audio. Granularization is now

performed on the last few seconds of audio kept in memory in the module.

B. Blending parameter/Audio quality button. Selects which of the blending parameters is controlled by

the BLEND knob and CV input, or selects one of the four audio quality settings.

C. Load/Save button. See the “Advanced topics” section.

D. Grain POSITION. Selects from which part of the recording buffer the audio grains are played. Turn the

knob clockwise to travel back in time.

E. F. Grain SIZE and PITCH (transposition). At 12 o’clock, the buffer is played at its original frequency.

G. Audio INPUT GAIN, from -18dB to +6dB.

H. Grain DENSITY. At 12 o’clock, no grains are generated. Turn clockwise and grains will be sown

randomly, counter-clockwise and they will be played at a constant rate. The further you turn, the higher the
overlap between grains.

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Mutable Instruments | Clouds

I. Grain TEXTURE. Morphs through various shapes of grain envelopes: square (boxcar), triangle, and then

Hann window. Past 2 o’clock, activates a diffuser which smears transients.

J. BLEND knob. This multi-function knob is described in the Blending parameters section.

K. Indicator LEDs. They work as an input vu-meter. When FREEZE is active, they monitor the output level.

Soft-clipping occurs when the last LED is on. They can also indicate the quality setting (red), the function
assigned to the BLEND knob (green), or the value of the four blending parameters (multicolor).

All CV inputs are calibrated for a range of +/- 5V. Voltages outside of this range are tolerated, but will be
clamped.

1. FREEZE gate input. When the input gate signal is high, stops the recording of incoming audio, just as

latching the FREEZE button would do.

2. TRIGGER input. Generates a single grain. By moving the grain DENSITY to 12 o’clock, and sending a

trigger to this input, Clouds can be controlled like a micro-sample player. An LFO or clock divider (or even
a pressure plate) can thus be used to sow grains at the rate of your choice.

3. 4. Grain POSITION and SIZE CV inputs.

5. Grain transposition (PITCH) CV input, with V/Oct response.

6. BLEND CV input. This CV input can control one of the following functions depending on the active

blending parameter: dry/wet balance, grain stereo spread, feedback amount and reverb amount.

7. 8. Stereo audio input. When no patch cable is inserted in the right channel input, this input will receive

the signal from the left channel.

9. 10. Grain DENSITY and TEXTURE CV inputs.

11. 12. Stereo audio output.

The BLEND knob can control one of these four settings:

Dry/wet balance.
Stereo spread (amount of random panning/balance applied to the grains).
Feedback amount.
Reverberation amount.

To select which parameter is controlled by the BLEND knob and the BLEND CV input, press the Blend

parameter/Audio quality button. The current parameter is temporarily indicated by a green LED.

When turning the BLEND knob, the color of the four status LEDs temporarily shows the value of the four
blending parameters (from black when the parameter is set to its minimum value to green, yellow and then
red for the maximum value).

It could happen that the position of the knob does not match the value of the parameter - the curse of
multi-function knobs! If this is the case, turning the BLEND knob clockwise (resp. counterclockwise)
causes a small increase (resp. decrease) in the value of the parameter, and turning it further causes larger
changes, until the value progressively catches up with the knob’s position.

There are a few things worth knowing about these settings:

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