K E T H E R E S

clouds in a guitar pedal

 

Reverb gives your music the sound of being played live in a music hall, copying and delaying parts of the sound before adding them back in to simulate echo. More complex effects give you the ability to simulate a room as small as a bar, or as large as a stadium, along with different acoustic elements. But what if you could simulate much more detailed and abstract soundscapes, like a windy autumn forest, or a complex-valued fractal? That's the power of granular sound texture synthesis, and it's the basis of Mutable Instruments' open-source Clouds module, the foundation of Ketheres. 

Clouds does for your keys and strings what cathedrals and opera houses do for the human voice - and what's more, it lets you choose and alter the floorplan at will. Sampling, chopping, delaying, reverberating, pitch-shifting, and sowing bits of the input signal back into itself puts any voice you choose into an infinity of soundscapes. But for most musicians, Clouds had a major limitation: its being made exclusively for the Eurorack modular synthesis form factor. Modular synthesis is a bit like shaving with a straight razor: powerful and versatile, but with a steep learning curve, and extra work for the end user. That's where Ketheres comes in. 

Ketheres is a Clouds build specifically designed for use with instrument effects pedal boards in live performance. Great care has been taken to ensure that the core circuitry is as close to the original design as possible - including an identical chipset, compatible with any firmware the original can run - but Ketheres also greatly simplifies the control inputs, moving key functions into foot-actuated controls to keep the user's hands free, including:

A model of the Ketheres faceplate.

  • an LED indicator stomp switch toggle for true bypass, ensuring the signal passing through is unaffected when its output is off, and reducing possible interference with neighbors in the signal chain.
  • a momentary stomp switch that can either freeze the input buffer, or trigger the generation of a sample "grain" at will, at the flip of a switch.
  • an expression pedal input jack in the most common TRS configuration, with reference voltage, that can be directed with its center black knob to any of the six parameters of the granular synthesizer.

Randomness is essential to many dynamic soundscapes, but Clouds required an external module to generate this input. With Ketheres, it's all on board, including:

  • a noise source, which can be shifted continuously between blue, white, and red noise, as well as an extreme low-pass filter that, when active, effectively makes the filtered noise output resemble a randomized LFO. 
  • a selector switch to choose between raw colored noise, low-pass-filtered noise, or no noise input, along with a white knob in the center to direct it to any of the granular synthesis parameters.

Ketheres also makes it much easier to put granular synthesis into your signal chain, with tweaks including:

  • Mono/stereo input selector, allowing both mono TS and stereo TRS plugs to be used, as well as separate L and R output jacks, all of standard 6.35mm (1/4") size, further simplifying signal chain integration with any combination of mono and stereo elements.
  • Standard DC 9V 2.1x5.5mm barrel jack power input, drawing less than 3W in normal operation, making it a breeze to plug into most pedal board power supplies, or power with an off-the-shelf adapter.
  • Custom-designed and color-coded 3D-printed input knobs with high-visibility, reflective, 3D indicators and glyphs, to ensure that sound checks and live changes are as foolproof as possible in the highly variable visual environment of a typical venue stage.

Furthermore, all of the great features of the original are preserved, such as:

  • Four green-red LEDs that can function together as a dynamic volume indicator for the input gain, or individually as indicators for selected parameters like reverb, feedback, or stereo spread.
  • A toggling freeze button to hold the input buffer constant, allowing the user to operate the pedal like a sampler.
  • The ability to save and recall up to four frozen buffers in memory, letting the user carry a micro-bank of their favorite waveforms to chop - or create them on the fly, as with a traditional sampler.

And this is only one of its modes! The stock Clouds firmware has 3 alternate modes, including a time-stretcher/pitch-shifter, a looping delay, and a spectral processor. Ketheres comes preloaded with the powerful, open-source Parasites firmware, which further adds a polyphonic resonator, an advanced reverb mode, an enhanced looping delay, and more options for grain size and envelope shape.

All of this is packed onto a single board in a 6"x4"x2" box, ready to spread your instruments into rainbows of sound.