dual-looping-delay

4ms Dual Looping Delay

Dual synchronized delay and looper with clock sync and reverse

20 HP Eurorack module

The 4ms Dual Looping Delay (DLD) is a dual-channel digital delay and looper with sample-accurate clock synchronization. Each channel offers nearly 3 minutes of delay/loop time at 48kHz/16-bit, with features including infinite hold looping, reverse playback, send/return for external feedback processing, and 1V/oct tracking for Karplus-Strong resonant delays.

Features

  • Dual independent delay/loop channels
  • Nearly 3 minutes per channel at 48kHz/16-bit
  • Sample-accurate clock synchronization
  • Infinite Hold looping mode
  • Reverse playback per channel
  • Send/Return per channel for external feedback processing
  • 1V/oct tracking for resonant delays
  • CV and trigger control for all major features
  • Normaled I/O for mono, stereo, or cascade use
  • Open-source firmware

Controls & Jacks (37)

  • Time A— Sets delay/loop time for channel A as a division or multiplication of the clock. Ranges from 1/16th of a beat to 32x the beat. At short time
  • Time B— Sets delay/loop time for channel B. Same range as Time A. When cascaded (B fed from A), creates complex rhythmic echo patterns.
  • Regen A— Controls feedback amount for channel A. 0% = single repeat, 100% = infinite sustain, 110% = self-oscillation. The sweet spot for looping is
  • Regen B— Controls feedback amount for channel B. Same range as Regen A. High regeneration with short times creates metallic resonant tones.
  • Feed A— Cross-feed from channel B into A's feedback path. Creates cascading stereo delay patterns. At 100% the full B signal enters A's feedback loo
  • Mix A— Wet/dry blend for channel A output. Full CCW = dry only, full CW = wet only, center = equal mix. Normalled to Out A jack.
  • Mix B— Wet/dry blend for channel B output. Same behavior as Mix A.
  • Feed B— Cross-feed from channel A into B's feedback path. Complement of Feed A for bidirectional cascading.
  • Ping— Tap tempo / clock input. Sets the master beat for both channels. Accepts gates, triggers, or audio-rate signals for Karplus-Strong effects.
  • Clock— External clock input. Similar to Ping but specifically for clock signals from sequencers or clock modules like the QCD.
  • Loop A— Gate input to toggle looping on channel A. High gate = loop engaged (infinite hold). Captures audio and plays it back continuously.
  • Loop B— Gate input to toggle looping on channel B. Same behavior as Loop A.
  • 1/8 A— Trigger input that divides channel A's time by 8 while held. Creates rapid stutter/glitch effects. Release returns to normal timing.
  • 1/8 B— Trigger input that divides channel B's time by 8 while held. Same behavior as 1/8 A.
  • In A— Audio input for channel A. Normalled to In B — a signal patched here feeds both channels unless B has its own input.
  • Return A— Returns externally processed audio back into channel A's feedback loop. Patch from Send A through effects and back here.
  • Rev A— Trigger/gate input and button to toggle reverse playback on channel A. Reverses the direction of the delay buffer playback.
  • Rev B— Trigger/gate input and button to toggle reverse playback on channel B.
  • Return B— Returns externally processed audio back into channel B's feedback loop.
  • In B— Audio input for channel B. If unpatched, receives the signal from In A (normalled connection).
  • Out A— Main audio output for channel A. Carries the wet/dry mix set by the Mix A knob.
  • Send A— Sends channel A's delayed signal out for external processing (e.g., filter, distortion) before it returns to the feedback loop via Return A.
  • Hold A— Gate input for infinite hold on channel A. While gate is high, the current delay buffer loops infinitely. New audio can be windowed in over
  • Hold B— Gate input for infinite hold on channel B. Same behavior as Hold A.
  • Send B— Sends channel B's delayed signal out for external processing via Return B.
  • Out B— Main audio output for channel B. Normalled from Out A — if nothing is patched into In B, Out B carries channel A's output.
  • Time A CV— CV input for modulating Time A. Sweeps through time divisions smoothly. At audio rates with short delays, creates pitched resonant effects.
  • Regen A CV— CV input for modulating Regen A. Useful for ducking feedback with an envelope or building feedback swells.
  • Feed A CV— CV input for modulating the cross-feed amount into channel A.
  • Feed B CV— CV input for modulating the cross-feed amount into channel B.
  • Regen B CV— CV input for modulating Regen B.
  • Time B CV— CV input for modulating Time B. Same behavior as Time A CV.
  • Rev A— Trigger/gate input and button to toggle reverse playback on channel A. Reverses the direction of the delay buffer playback.
  • Rev B— Trigger/gate input and button to toggle reverse playback on channel B.
  • +16 A— Button to multiply channel A's delay time by 16. Toggles between normal and 16x extended time. Useful for switching between short rhythmic d
  • Infinity— Button to engage infinite hold on both channels simultaneously. Captured audio loops forever. New audio can be layered on top by adjusting t
  • Ping Pong— Button to toggle ping-pong mode. Audio bounces between channels A and B, creating a stereo ping-pong delay effect.

How-To Guides

  • Synchronized Stereo Delay
  • Live Looping Performance
  • Karplus-Strong Resonant String
  • Cascading Delay Chain
  • Reverb-Like Dual Delay
  • Pressure-Controlled Sound-on-Sound

Explore the interactive Dual Looping Delay panel on BleepDex — tap any control to learn what it does.

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