Erica Synths Black Octasource Manual (PDF)
As a Eurorack musician, the Erica Synths Black Octasource offers rich, multi-output LFO capabilities that transcend conventional modulation roles. Its unique features—such as 8 phase-shifted outputs, waveform morphing, FM, CV control over phase and waveform, external sync, and flexible output modes—open up experimental territories for making powerful percussive, bass-heavy, and ethereal sounds. Below are techniques tailored to your interest in distorted percussion, aggressive basslines, and haunting pads.
A. Audio-Rate Modulation (Turning LFO into Oscillator/Modulator) - Patch: Crank the RATE control into its highest setting (up to 30Hz). Patch one or more outputs into the FM or AM (audio-rate) input of a VCO or a filter. - Result: Fast, phase-shifted LFOs create metallic, clangorous, or broken digital percussion when used as FM sources, especially if the waveform is ramp, S&H, or sharply morphs.
B. Multi-Output Rhythm Driver - Patch: Use MULTI mode for different waveforms on each output. Patch 2–3 outputs into several percussion LPGs or envelope generators. Each gets a different rhythmic modulation due to phase shifts. - Result: Generates complex, shifting rhythm beds. If used with VCAs and distortion modules, it produces wildly throbbing, glitched percussion textures.
C. Unipolar Percussive FM - Tip: Switch to unipolar output (+0V to +5V) for envelope/FM modulation of pitch or cutoff in classic synth drum sounds (see manual: Set RATE to 12 o’clock + MUL/SING switch 6x). - Result: Removes unwanted negative voltage "pop," accentuating the attack phase and sharper percussive snap.
A. Sync to Master Clock for Groovy Modulation - Patch: Patch your DAW or sequencer clock into SYNC. Now the LFO modulates in sync (RATE knob freezes modulation except in “freeze” mode). - Result: Ensures your wobbles hit exactly on the beat—vital for modern bass music.
B. Eight-Phase Wobble Modulation - Patch: In SINGLE mode, take several outputs (e.g., at 0°, 45°, and 90°) and modulate multiple parameters: filter cutoff, resonance, waveshaper amount, or VCA level. - Example CV Routing: Output 1 → Filter cutoff, Output 2 → Oscillator FM, Output 3 → VCA CV. - Result: Each parameter modulates with a different phase, yielding morphing, interlocking wobble-bass movement typical of complex dubstep/Drum & Bass lines.
C. FM Feedback for Aggressive Distortion - Patch: Patch an Octasource output into its own FM IN. Use another output/CV to modulate FM LEVEL knob by hand or via CV. - Result: Self-FM introduces pitch warble and chaotic distortion. Tame with downstream filter or distortion for modern, aggressive textures.
A. Multi-Parameter Pad Mod - Patch: Use several Octasource outputs to subtly modulate parameters such as reverb mix, chorus rate, or multiple oscillator levels/panning. - Result: The slow drift between outputs (at sub-audio LFO rates) provides an organic, ever-evolving motion in stereo or surround field—perfect for haunting pads.
B. Morphing Ambience - Patch: Choose MULTI mode. Use the WAVE knob or CV to morph between outputs, routing them to FM/AM/shaping inputs on digital or analog oscillators. - Result: Smoothly morphing waveforms at different phases create unpredictable artifacts—great for surreal modulated textures under pad layers.
C. Freeze for Timeless Modulation Snapshots - Patch: Engage Freeze (RATE at 12 o’clock or via external clock). This holds the CV state. Unfreeze for dramatic changes. - Result: Create shimmering, frozen modulations or time-suspending transitions in ambient and cinematic builds.