Bifold

Intellijel 8HP
WAVEFOLDER WAVESHAPER EFFECTS

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Dual-channel wavefolder. P channel is a Buchla-style parallel deadband folder; S channel is a Serge-style serial folder. Built-in crossfader, symmetry bias, phase invert and AUX sum enable ring/AM modulation tricks.

Patch Ideas · 6

★ Sine to square evolution
Sine → IN P · slow LFO >> FOLD P CV · FOLD P attenuator ~3 o'clock · FOLD knob at noon · MIX out · as CV sweeps, sine gains odd harmonics then approaches square
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: LFO, VCO, Bifold, Output. Signals: 2 audio, 1 cv.LFOVCOBifoldOutputOutcvSineaudioIN PaudioFOLD PcvMIXaudioInaudioaudiocv
★ Stereo fold
Sine → IN P · IN S normals from IN P · OUT P → left · OUT S → right · set SYM-X-AUX (P) to SYM with bias · leave S at X · two fold flavours panned L/R for wide stereo image
▸ Show diagram
Patch diagramPatch diagram with 3 modules and 3 connections. Modules: Bifold, VCO, Output. Signals: 3 audio.BifoldVCOOutputSYM-X-AUX (P): SYMSYM-AUX (P) attenuator: ~2 o'clockSYM-X-AUX (S): XIN PaudioOUT PaudioOUT SaudioSineaudioLeftaudioRightaudioaudio
Ring modulator
Carrier sine → IN P · modulator sine → XFADE CV · both SYM-X-AUX to X · both XFADE selects to IN · PHASE switch up · XFADE knob at noon to null · MIX = clangorous sum/difference
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Bifold, VCO 1, VCO 2, Output. Signals: 2 audio, 1 cv.BifoldVCO 1VCO 2OutputSYM-X-AUX (P): X · SYM-X-AUX (S): XXFADE P: IN · XFADE S: INPHASE: ON · XFADE knob: noonIN PaudioXFADE CVcvMIXaudioSineaudioSinecvInaudioaudiocv
Self-patched chaos noise
Nothing patched to IN P/S · both SYM-X-AUX to AUX · AUX unpatched (normals to MIX) · twist FOLD, XFADE and SYM-AUX attenuverters · self-oscillating hiss, clicks, squawks
▸ Show diagram
Patch diagramPatch diagram with 2 modules and 1 connection. Modules: Bifold, Output. Signals: 1 audio.BifoldOutputSYM-X-AUX (P): AUX · SYM-X-AUX (S): AUXAUX jack: unpatched (normals to MIX)FOLD: ~2 o'clockMIXaudioInaudio11. self-feedback via AUX normalaudio
Wet/dry fold crossfade
Triangle → IN P · XFADE P select = FOLD OUT P · XFADE S select = IN S (dry) · XFADE knob = wet/dry · slow LFO >> XFADE CV for breathing timbre
▸ Show diagram
Patch diagramPatch diagram with 4 modules and 3 connections. Modules: Bifold, LFO, VCO, Output. Signals: 2 audio, 1 cv.BifoldLFOVCOOutputXFADE P: FOLD OUT PXFADE S: IN S (dry)IN PaudioXFADE CVcvMIXaudioOutcvTriaudioInaudioaudiocv
Chaotic dual CV fold
Single osc → IN P (S takes the normal) · envelope >> FOLD P · independent LFO >> FOLD S · two folders receive different modulation · IN S dummy-cabled breaks normal for fully independent drives
▸ Show diagram
Patch diagramPatch diagram with 5 modules and 5 connections. Modules: Bifold, ENV, LFO, VCO, Mixer. Signals: 3 audio, 2 cv.BifoldENVLFOVCOMixerStereo folding setup: IN PaudioFOLD PcvFOLD ScvOUT PaudioOUT SaudioOutcvOutcvSawaudioLaudioRaudioaudiocv

Behaviors

Two fold flavours route audio to IN P vs IN S

P channel is a Buchla-style parallel deadband folder — symmetrical, opens from silence. S channel is a Serge-style serial stack — softer, denser harmonics. Each sounds distinct with the same input.

IN S normal leave IN S unpatched

IN P is internally routed to IN S. One patched source drives both folders simultaneously — ideal for XFADE blending and stereo folding via OUT P / OUT S.

AUX feedback loop SYM-X-AUX switches in AUX + AUX jack unpatched

AUX input normals to the MIX output. Setting either channel's SYM-X-AUX to AUX creates an internal feedback path — generates chaotic noise, squawks and self-oscillation with nothing else patched.

Ring modulator PHASE switch ON · both XFADE selects IN · SYM-X-AUX = X

With S inverted and both folders bypassed (IN selects), XFADE knob nulls the two inputs. Patching a second oscillator to XFADE CV multiplies it against IN P — ring modulation output at MIX.

Amplitude modulation ring modulator setup + dummy cable in IN S

Breaks the IN S-from-IN P normal. The XFADE CV signal then amplitude-modulates (rather than ring-modulates) the IN P signal.

SYM bias asymmetry SYM-X-AUX → SYM

Adds a ±5V DC offset before the folder. Breaks symmetric fold into biased fold — the waveform folds more on one polarity than the other, producing PWM-like timbres and even harmonics.

Wet/dry XFADE XFADE P or S select → IN

Feeds the raw input (not folded) to that side of the crossfader. XFADE knob then acts as wet/dry between dry input and the opposite channel's folded output.

FOLD knob silence trap FOLD fully CCW + FOLD P attenuator CCW + no FOLD P patch

With FOLD at minimum and the attenuator at zero, no signal passes to the outputs. Turn the attenuator up (+5V internal normal) or raise FOLD to hear output.

Controls

Global FOLD Master fold depth applied to both IN P and IN S. Fully CCW = no folding (unless CV overrides).
Sums with FOLD P and FOLD S CV · interacts with each attenuator
MIX out XFADE Crossfades between Parallel and Serial folder outputs at the MIX jack. CCW = P only · noon = equal mix · CW = S only.
±5V CV attenuverted by XFADE knob [15]
Parallel folder SYM-X-AUX switch (P) Three-position input bias select for IN P. SYM adds DC offset (asymmetry) · X = clean · AUX sums the AUX jack into IN P.
Offset/AUX amount set by SYM-AUX attenuverter [5]
Serial folder SYM-X-AUX switch (S) Three-position input bias select for IN S. SYM adds DC offset · X = clean · AUX sums the AUX jack into IN S.
Offset/AUX amount set by SYM-AUX attenuverter [6]
Parallel folder SYM-AUX attenuverter (P) Attenuverts either the ±5V DC bias (SYM position) or the AUX input (AUX position). Inactive in X position.
±5V DC · bipolar
Serial folder SYM-AUX attenuverter (S) Attenuverts either the ±5V DC bias (SYM position) or the AUX input (AUX position). Inactive in X position.
±5V DC · bipolar
Serial folder → XFADE PHASE switch Inverts the phase of the Serial folder signal fed to the XFADE/MIX. Enables ring-modulation cancellation and subtle mix colour shifts.
Up = inverted · down = in phase
XFADE input XFADE P select Selects what feeds the P side of the crossfader. FOLD OUT P (up) = folded P · IN P (down) = dry P (wet/dry across XFADE).
Up/down toggle
XFADE input XFADE S select Selects what feeds the S side of the crossfader. FOLD OUT S (up) = folded S · IN S (down) = dry S.
Up/down toggle
Parallel folder FOLD P attenuator Attenuates the FOLD P CV input. When no jack is patched, internally normals +5V — the knob then acts as a 0–5V fold offset.
0–5V normal · unipolar
Serial folder FOLD S attenuator Attenuates the FOLD S CV input. If FOLD S is unpatched, the FOLD P jack (or its internal +5V normal) also feeds the Serial folder CV.
0–5V normal · unipolar
XFADE CV XFADE attenuverter Scales and optionally inverts the XFADE CV input. CW = positive unity · noon = zero · CCW = inverted.
±5V CV · bipolar
MIX out MIX LED Brightness shows level at MIX. Red = negative · green = positive · orange = audio rate.
Bipolar indicator
Per channel OUT P LED / OUT S LED Per-folder output indicator. Same red/green polarity convention as MIX LED.
Bipolar indicator

I/O

IN · 6

  • IN P ±5V typical AUDIO
    Audio input to the Parallel (Buchla-style deadband) folder
  • IN S ±5V typical AUDIO
    Audio input to the Serial (Serge-style) folder
    NORM → IN P when unpatched
  • AUX ±5V
    Auxiliary input summed into IN P and/or IN S when the respective SYM-X-AUX switch is in AUX position
    NORM → MIX output when unpatched (enables feedback)
  • FOLD P ±10V CV
    ±10V CV for Parallel fold amount. Positive increases fold · negative decreases it.
    NORM → +5V when unpatched
  • FOLD S ±10V CV
    ±10V CV for Serial fold amount
    NORM → FOLD P jack when unpatched
  • XFADE ±5V CV
    ±5V CV for P/S crossfade at MIX out

OUT · 3

  • OUT P ±5V
    Parallel folder direct output
  • OUT S ±5V
    Serial folder direct output
  • MIX ±5V
    Crossfaded sum of Parallel and Serial (post PHASE switch)