Oneiroi — Befaco · Eurorack Reference

Capabilities 7

Delaydelay: 2-tap ping-pong delay from 10ms to 4 seconds with feedback and optional DJ-style filter. Can sync to external clock.643
LFOlfo: Multiple modulation sources: Sine LFO, Ramp LFO, Sawtooth LFO, Square LFO, S&H, Chaos, and Envelope Follower. Rate from ~0.01Hz to ~3Hz unsynced (max 80Hz). Assignable to any knob parameter.643
Looperlooper: 5-second stereo looper with varispeed (2x reverse to 2x forward), start/length controls, sound-on-sound, and pre/post recording selection.643
Multimode Filtermultimode-filter: 2-pole stereo filter switchable between LP, BP, HP, and comb. Can be repositioned in the effects chain. Unique chaotic noise generator activates past 75% resonance.643
Reverbreverb: Ambience processor loosely based on a Schroeder reverberator, with macro SPACETIME control for size/filtering/direction, decay control, and synchronized auto-panner.643
Stereo Synthesizerstereo-synthesizer: Full stereo signal path with 3 oscillators (sine, supersaw, wavetable), 4 effects, and a looper. Built on the Rebel Technology OWL mk3 platform.643
Vcfvcf: 643

Jacks 20 — 18 in / 2 out

Name	Signal	Voltage	Description
Inputs (18)
Ambience Spacetime CV	cv	-5V to 10V	643
Detune/Offset CV	cv	-5V to 10V	643
Dry/Wet CV 1	cv	0V to 10V	643
Dry/Wet CV 2	cv	0V to 10V	643
Echo Density CV	cv	-5V to 10V	643
Filter Cutoff CV	cv	-5V to 10V	643
Looper Length CV	cv	-5V to 10V	643
Looper Speed CV	cv	-5V to 10V	643
Looper Start CV	cv	-5V to 10V	643
Random In	gate	≥1V	Randomizes the parameters when receiving a high signal (>1V).643
Record In	gate	≥0V	Gate input for recording. Starts recording when high (>1V) and stops when low (0V).643
Resonator Tune CV	cv	-5V to 10V	643
Stereo Input L(M)	audio	—	Left channel stereo input; normals to right channel if only one cable is connected.643
Stereo Input R	audio	—	643
Sync In	clock	≥1V	Synchronizes the LFO and delay time to an external source and resets the looper to the start point. Accepts triggers of a minimum of 1V. Supported clock speed from 30 BPM to 300 BPM.643
V/Oct In	cv	0V to 10V	Common V/Oct input for all three oscillators, summed to the PITCH knob. Tracks 10 octaves over 0–10V range.643
Volume CV 1	cv	0V to 10V	CV input affecting the level of one of the four signal sources.643
Volume CV 2	cv	0V to 10V	643
Outputs (2)
Stereo Output L	audio	—	643
Stereo Output R	audio	—	643

Parameters 26

Name	Type	Range	Behavior
Ambience Decay	knob	—	Controls how long the reverb tail takes to fade out.643
Ambience Spacetime	knob	—	Macro control for reverb size, filtering, and direction. At 50%: smallest size and brightest tone. At 0% or 100%: biggest size and darkest tone. Below 50%: input signal is reversed. SHIFT + SPACETIME changes auto-pan amount and frequency division from 0% (no auto-pan) to 100% (full auto-pan at 8x base frequency) with 16 different ratios.643 Zones Reversed Forward Reversed -100–0%Input signal is reversed into the reverb. Bigger size and darker tone toward the extremes.643 Forward 0–100%Input signal plays forward into the reverb. At noon (50%) smallest and brightest; toward 100% bigger and darker.643
Detune/Offset	knob	—	Controls supersaw detuning (in supersaw mode) or wavetable selection from 32 wavetables (in wavetable mode). SHIFT + DETUNE alters interval between oscillators: 0% = one octave down, 100% = one octave up, default 50% = unison.643
Dry/Wet Faders	fader	—	Manual controls for the dry/wet ratio of the four FX processors (constant power response). When CV jacks are patched, become attenuators of the incoming CV. At lowest position, signal passes through unaffected.643
Echo Density	knob	10ms – 4000ms	Delay time control for a 2-tap ping-pong delay, from 10ms to 4 seconds. When synced, becomes a clock divider. SHIFT + DENSITY applies a DJ-style filter to the echo: noon = no filter, CW = HPF, CCW = LPF.643
Echo Repeats	knob	0% – 100%	Feedback control for the echo effect, from one repeat at 0% to infinite at 100%.643
Filter Cutoff	knob	10Hz – 22000Hz	Controls filter frequency cutoff (approximately 10Hz to 22kHz) in multimode filter mode, or notch position in comb filter mode. SHIFT + CUTOFF selects filter type (LP, BP, HP, comb).643
Filter Resonance	knob	—	Controls filter resonance. Past 75%, activates a chaotic noise generator whose output is combined with the input and filtered. SHIFT + RESO sets the filter position in the effects chain (positions I–IV).643
Input Gain Switch	switch	—	Three-position switch selecting input gain: top position for high-impedance sources (microphones), middle for line-level, bottom for Eurorack module outputs.643
Looper Length	knob	0% – 100%	Changes the size of the loop with an exponential curve, from ~8 ms at 0% up to the full buffer length at 100%. SHIFT + LENGTH sets the SOS DJ-style filter response.643
Looper Start	knob	—	Sets the starting point of the loop. When SHIFT is held and START is turned, sets the SOS (Sound on Sound) level from 0% (old material constantly replaced) to 100% (never fades away).643
Looper Varispeed	knob	0% – 100%	Controls looper direction and playback speed. At 0% plays at 2x reverse, at 50% (12:00) the looper is stalled. At 100% plays at 2x forward. Virtual detents at -1x, 0, and 1x.643 Zones Stalled Stalled 0–0%At 12:00 (noon), the looper is stalled (stopped).643
Mod/CV Amount Button	button	—	Blinks RED for modulation mapping mode; blinks GREEN for CV mapping mode. Hold 2 seconds to save current state to flash.643
Modulation Level	knob	—	Master control for the intensity of all modulation. Prevails over all modulation mappings.643
Modulation Speed	knob	—	Controls base frequency of modulation from 1/16x to 16x with common time divisions. Unsynced base is ~0.2Hz (range ~0.01Hz to ~3Hz). SHIFT + SPEED selects modulation type (sine LFO, ramp, sawtooth, square, S&H, chaos, envelope follower). For envelope follower, controls slope of envelope curve.643
Oscillator Mode Switch	switch	—	Selects between supersaw oscillator (up) and wavetable oscillator (down). These two oscillators are mutually exclusive.643
Pitch	knob	-6semitone – 6semitone	Controls pitch for all oscillators. Centered on C, spans 6 semitones on either side. SHIFT + PITCH selects the current octave. Full pitch range of oscillators is 8 octaves (C0 to C7).643
Pre/Post Switch	switch	—	Selects whether the looper records the stereo input (PRE) or the module's output (POST). Also determines what the envelope follower and peak meter monitor.643
Randomization Amount	switch	—	Three-position switch: top = full-range randomization, middle = ±20% variation, bottom = ±2% variation.643
Randomization Target	switch	—	Four-position switch selecting which units are randomized: All units, Oscillators only, Looper only, or Effects only.643
Randomize Button	button	—	Press to randomize immediately. Hold for desired duration then release for gradual morphing. SHIFT + RANDOM = undo/redo randomization. SHIFT + RECORD + RANDOM = reset all parameters to knob positions.643
Record Button	button	—	Toggle: single press toggles recording on/off. Momentary: hold to record, release to stop. SHIFT + RECORD clears the buffer.643
Resonator Feedback	knob	—	Generates sustained resonance. At 100% causes the resonator to self-oscillate.643
Resonator Tune	knob	—	Changes the base frequency of three comb filter instances using three different ratios. SHIFT + TUNE makes resonance more dissonant (default 0%).643
Shift Button	button	—	Accesses secondary parameters (white background labels). Momentary: hold while changing a parameter. Toggle: single press turns on/off. SHIFT state must be saved to persist after power cycle.643
Volume Faders	fader	—	Manual controls for the four audio source volumes (exponential response). When CV jacks are patched, become attenuators of the incoming CV.643

Firmware history 0 versions

No firmware history recorded.

References 2

[643]
Befaco Oneiroi User Manualmanual
source 643 canonical ↗ archived ↗

● verified 2026-05-21
[644]
Befaco Oneiroi product pageproduct_page
source 644 canonical ↗ archived ↗

● verified 2026-05-21