rungler new

rungler

a circuit-bent chaotic synth voice for norns

two oscillators cross-modulate through an 8-bit shift register. the register feeds back into itself through XOR logic, creating stepped voltage patterns that hover between order and chaos. a twin peak resonator sculpts the output. a gate sequencer turns the rungler into a rhythmic engine. wavefolder, bit crusher and feedback delay bend the circuit further. four stereo panning modes spread the chaos across the field.

inspired by Rob Hordijk's Benjolin & Blippoo Box — "bent by design."

requirements

• norns (shield, standard, or fates)
• no additional libraries required

install

from maiden:

;install https://github.com/semi/rungler

controls

navigation

control	function
E1	page select (6 pages)
K1 held	show attractor plot
K2	toggle alt mode
K3	randomize current page
K1 + K3	reset all to defaults

page 1: OSC

control	normal	alt
E2	osc A frequency	rungler → osc A depth
E3	osc B frequency	rungler → osc B depth

page 2: RUNGLER

control	normal	alt
E2	chaos (recycle ↔ XOR)	register length (3–8)
E3	rungler → filter depth	output select

output modes: filter / osc a / osc b / xor / pwm / rungler

page 3: GATE

control	normal	alt
E2	gate threshold	gate attack
E3	gate release	gate mode (free/gated)

the gate sequencer turns the rungler into a rhythm machine. on each clock tick (osc B), the gate opens only if the rungler CV exceeds the threshold. different oscillator frequency ratios and chaos settings produce different rhythmic patterns.

page 4: FILTER

control	normal	alt
E2	cutoff frequency	filter type (LP/BP/HP/Twin)
E3	resonance	peak spread

twin peak mode runs two bandpass filters in parallel with offset frequencies — inspired by the Blippoo Box resonator. the peak spread parameter controls the frequency ratio between the two peaks.

page 5: FX

control	normal	alt
E2	wavefold amount	bit crush depth
E3	delay time	delay feedback

page 6: SPACE

control	normal	alt
E2	auto-pan depth	pan mode
E3	stereo width	volume

pan modes:

• manual: static position
• rungler: rungler CV drives panning
• random: new random position on each gate trigger
• lfo: osc B triangle sweeps the stereo field

stereo width adds Haas-effect micro-delay to the right channel, widening the image.

attractor plot

hold K1 to see the return map: each point plots rungler CV(t) on X against rungler CV(t-1) on Y. at low chaos, you see discrete clusters (looping patterns). at high chaos, a structured cloud emerges — the chaotic attractor.

architecture

rungler/
  rungler.lua                  main entry point
  lib/
    Engine_Rungler.sc          SuperCollider engine
    ui.lua                     screen drawing (6 pages + attractor)
    core.lua                   parameters, polls, state

signal flow

                    ┌──────────────────────────────┐
 OSC_A (tri+pulse) ─┤                              ├─► RUNGLER
                    │     cross modulation          │   (8-bit shift register)
 OSC_B (tri+pulse) ─┤                              │       │
                    └──────────────────────────────┘       │
                            ▲                              │
                            │ feedback                     ▼
                            │                         ┌─────────┐
                            └──── 3-bit DAC ◄─────────┤ XOR/loop│
                                     │                └─────────┘
                                     │
                    ┌────────────────┼────────────────┐
                    │                │                │
                    ▼                ▼                ▼
              gate envelope    filter freq      osc freq
                    │                │
                    ▼                ▼
         PWM (triA vs triB) ──► FILTER (LP/BP/HP/Twin Peak)
                                     │
                                wavefolder
                                bit crusher
                                feedback delay
                                     │
                               gate envelope
                                     │
                             stereo pan + width
                                     │
                                     ▼
                                 stereo out

no sc3-plugins required

the engine uses only vanilla SuperCollider UGens. the shift register is built from Latch.ar + Delay1.ar chains. XOR is computed as a + b - 2ab for audio-rate binary signals. the twin peak filter uses two standard BPF UGens in parallel.

tips

• finding chaos: start with A=80Hz, B=3Hz, chaos=0.5. slowly turn up rungler→A. the boundary between stable and chaotic is where the music lives.
• rhythmic patterns: enable gate mode. threshold determines density. low threshold = many gates = dense. high threshold = sparse. osc B frequency = tempo.
• twin peak vowels: set filter type to Twin, resonance high (>1.0), peak spread around 2.0. sweep cutoff slowly. the interaction between the two peaks creates vowel-like timbres.
• stereo chaos: set pan mode to "rungler", depth to 0.7, width to 0.5. the signal bounces across the stereo field following the chaotic CV.
• attractor watching: hold K1 while adjusting chaos. watch the return map transition from discrete points (loop) through bifurcation to a full chaotic attractor.
• extreme territory: osc B at 0.1Hz = glacial evolution. osc B at 2kHz = metallic timbre. fold + crush together = circuit destruction.

acknowledgments

• Rob Hordijk for the Benjolin design, Blippoo Box twin peak resonator, and "bent by design" philosophy
• Alejandro Olarte for the SuperCollider Benjolin implementation
• scazan for the original norns benjolis script
• Derek Holzer (macumbista) for Pure Data Benjolin documentation
• the lines community

license

MIT