Sync Reverser

A clock-synced granular reverse effect. It chops incoming audio into grains and plays each one backwards, but instead of a fixed grain size it locks the length to a tempo division of a patched clock — so the reverse chunks land cleanly on the beat. Great for turning loops, drums, and vocal phrases into rhythmic backwards stutters that stay in time.

How it works

The effect records your stereo input into a ring buffer and, on each sub-beat, spawns a grain that reads back through it in reverse at unity pitch — so the audio plays backwards without changing key. Grain size comes from the clock: it measures the interval between rising clock edges to find the tempo, then divides by the Div setting. With the Clock control on Ext and no clock patched it sits at 120 BPM; Song follows the timeline's tempo instead. The Reset input snaps the grain grid back to the pulse so the backwards chunks align to the downbeat of an upstream loop.

Controls

  • Div — the tempo division each grain locks to, stepped from 1/32 up to 1/1 with dotted variants in between. Smaller values give fast, choppy reversals; larger values reverse longer phrases.
  • Len — grain length as a fraction of the sub-beat. At 1.0 the reversal is continuous; pull it down and the grains shorten into rhythmic backwards stabs with silence between them.
  • Mix — wet/dry blend, from fully dry (0%) to fully reversed (100%).
  • Shape — the edge fade on each grain window, from 0% (a hard rectangle that gives clicky, percussive reverse stabs) up to 50% (a soft triangle that smooths them into gentle backwards swells); around the default 5% you get the classic crisp stutter.
  • Clock — where the tempo comes from. Ext measures the pulses arriving at the clock input, which is how this module has always worked. Song follows the timeline's tempo directly, with no cable at all. Int runs at its own speed, set by the BPM field beside it. One thing worth knowing: in Ext the divisions are relative to whatever you clock it with, so feeding it sixteenths makes every label four times faster than it reads. In Int and Song the module knows what a quarter note is, so the labels mean exactly what they say.
  • BPM — the tempo for Int. In Song it greys out and shows you the timeline's tempo instead; in Ext it greys out too, because the cable is in charge.

Inputs & outputs

  • In L / In R — the stereo audio to reverse; both channels share the engine but keep their own width.
  • Div / Len / Mix / Shape CV — voltage control over each knob; patch an LFO or envelope for evolving, modulated stutters.
  • Clock — patch a clock here to set the tempo; the grain grid locks to it.
  • Reset — a trigger snaps the grain grid to the beat, aligning reversals with the start of a loop.
  • Out L / Out R — the processed stereo output.

Tips

  • Feed it the same clock and reset that drive your loop so the backwards chunks lock to the bar line.
  • Keep Len near 1.0 for a smooth backwards wash; back it toward 0.5 for glitchy, gated reverse rhythms.
  • Sweep Div CV with an LFO to ratchet between coarse and fine reversals.