In its tumultuous teenage years, Clouds tried to be everything, including a delay/pitch-shifter, a spectral processor, a projectionist and a cab driver in Rouen. This experimental code is still available in the module, by pressing the B button for 5 seconds until one of the LEDs glows in orange, and then repeatedly pressing the button to select one of 4 functions:
- (First LED lit) Granular processor (normal operation).
- (Second LED lit) Pitch shifter/time-stretcher.
- (Third LED lit) Looping delay.
- (Fourth LED lit) Spectral processor.
Home sweet home.
This mode is quite similar to the granular mode, except that it uses two overlapping grains synchronized with the most salient period of the sound. The grains are carefully spliced so that they mesh well with each other (a technique similar to the “deglitching” of early pitch-shifters). Modulating POSITION when recording is frozen will “scrub” through the audio buffer. Clouds’ uses classic time-domain methods which are not suitable for polyphonic or percussive material (unless this percussive material is breakbeats and you liked Akai samplers. Then: smile).
DENSITY creates a granular diffusion effect based on all-pass filters.
TEXTURE acts as a low-pass/high-pass filter.
SIZE controls the size of the overlapping windows used for pitch-shifting and time-stretching – from an extremely grainy “drilling” sound to smooth bits of loops.
Sending a trigger to the TRIG input creates a clock-synchronized loop (when FREEZE is enabled) or stuttering effect – equivalent to applying a tempo-synchronized decaying envelope on the POSITION parameter.
The looping delay mode continuously plays back audio from the buffer without any kind of granularization.
POSITION controls the distance between the playback head and the recording head (in other words, the delay time). Modulating POSITION will create effects similar to vinyl scratching or manual manipulation of tape.
When FREEZE is activated, the content of the audio buffer is looped (stutter effect). POSITION controls the loop start and SIZE the loop duration. DENSITY creates a granular diffusion effect based on all-pass filters; and TEXTURE acts as a low-pass/high-pass filter.
SIZE controls the size of the overlapping windows used for pitch-shifting – fully clockwise for a smooth result that might smear transients, fully counterclockwise for a grainy, almost ring-modulated sound.
When FREEZE is enabled, sending a trigger on the TRIG input creates a clock-synchronized stuttering loop. Otherwise, the period of the trigger pulses sets the delay time – provided this delay is shorter than the recording buffer size.
In this mode, the incoming signal is converted into “frames” of spectral data, that are stored, transformed, recombined, and resynthesized as a time-domain signal.
POSITION selects into which buffer the audio is poured (when FREEZE is not active), or from which buffer the audio is synthesised (when FREEZE is active). For example, set POSITION to its minimum value. Press FREEZE. You get a first texture. Set POSITION to its maximum value. UNFREEZE. Wait for something else to happen in the incoming audio. Press FREEZE again. By moving POSITION you interpolate between the two textures which had been captured at the press of FREEZE. Depending on the quality settings there are 2 to 7 buffers laid out over the course of the POSITION knob. What the module does is crossfade between a “wavetable” of FFT slices.
SIZE changes the coefficients of a polynomial that determines how frequencies are mapped between the analysis and synthesis buffers. It’s like a 1-knob GRM Warp. Over the course of the knob it’ll do spectral shifting, but also spectral reversal.
PITCH controls the transposition (pitch-shifting).
DENSITY determines how results from the analyzer are passed to the resynthesizer. Below 12 o’clock, there’s some increasing probability that a given FFT bin won’t get updated, causing a kind of partial freeze. After 12 o’clock, adjacent analysis frames are increasingly merged together (like a low-pass filter in the amplitude each frequency bin). At extreme settings, random phase modulation is applied to smooth things - giving you different flavours of spectral muddling/reverb.
TEXTURE does two things: below 12 o’clock, it increasingly quantizes the amplitudes of the spectral components, like a very low-bitrate audio file. After 12 o’clock, it increasingly weakens the strongest partials and amplifies the weakest ones. This has the effect of making the spectrum more noise-like.
Sending a trigger to the TRIG input creates various frequency-domain glitches typical of corrupted (encoded) audio files. It works as a kind of build-up/feedback effect - the shorter the pulse, the smaller the effect. With a continuous gate, it’ll really start to rot…