Noise Engineering Fractio Solum
CV-controlled fractional clock divider and multiplier
4 HP Eurorack module
Fractio Solum is a CV-controlled clock divider and multiplier that outputs rhythmic fractions of an input clock, displayed as an intuitive ratio (e.g. 3/4 means 3 triggers out for every 4 in). It excels at generating polyrhythms, polymeter, and unusual time signatures with musical precision. The module includes x2 and /2 outputs, a BOC (beginning of cycle) trigger, mute, and reset for complex rhythmic patching.
Features
- CV-controlled clock division and multiplication via fractional ratios
- Intuitive two-digit ratio display showing Out/In fraction
- Three ratio subsets selectable via 1-23-N/M switch: integer-only, powers-of-2-and-3, and full N/M table
- Encoder for manual ratio selection
- Ratio CV input accepting 0-5V for voltage control of ratio
- Mute function on all outputs via encoder press, phase-preserving
- RST input for resetting the clock cycle to the beginning
- Out jack at selected ratio
- x2 output at twice the selected ratio rate
- /2 output at half the selected ratio rate
- BOC output fires a trigger at the beginning of each cycle based on the /2 output (Out completes two cycles per BOC pulse)
- Trigger inputs respond to signals over +2V
Controls & Jacks (14)
- RST — Reset input. Resets the clock cycle to the beginning.
- BOC — Beginning of Cycle trigger output. Fires at the start of each clock cycle.
- Ratio — Sets the division/multiplication ratio. Press to mute/unmute all outputs while keeping time and phase.
- Ratio CV — CV input for ratio control. Expects positive voltage 0v to +5v.
- /2 — Clock output at half the rate of Out.
- x2 — Clock output at twice the rate of Out.
- Out — Clock output based on ratio. Outputs triggers at about +5v.
- In — Clock input. Triggers from any signal over +2v.
- Solum
- W/N-E2-T
- Mode — Selects ratio subset: 1 (1/x or x/1), 23 (factors of 2 or 3 only), or N/M (any fraction up to 10/10).
- 1-23-N/M — Selects ratio subset: 1 (1/x or x/1), 23 (factors of 2 or 3 only), or N/M (any fraction up to 10/10).
- Ratio (press/mute) — Pressing the Ratio encoder activates mute on all outputs; pressing again unmutes while keeping clock in time and phase
- Ratio CV input — CV input for ratio control. Expects positive voltage 0v to +5v.
How-To Guides
- Simple Clock Division
- Clock Multiplication for Rapid Subdivisions
- Classic Polyrhythm with Two Voices
- Polymetric Sequence Looping
- CV-Modulated Meter Changes
- Poly-Polyrhythm with Two Fractio Solum
- Rhythmic Envelope Modulation
- Tap Tempo Master Clock
- Preset Ratio Recall via Voltage Sequencer
- In-Time Mute for Live Performance
Explore the interactive Fractio Solum panel on BleepDex — tap any control to learn what it does.
