F_DRAWCV – Drawable Control Voltage Generator

F_DRAWCV is a trigger-based control voltage generator that lets you draw your own modulation shape. It is designed for creating custom CV movements for filters, pitch, amplitude, effects, stereo movement, ducking, rhythmic modulation, and experimental patch control. Unlike an audio waveform drawing module, F_DRAWCV does not generate audio directly. It generates control voltage based on a user-defined shape.

Basic Operation

Connect a gate or trigger signal to the TRIG input. Each rising trigger starts playback of the drawn shape from the beginning. The shape is played once over the time set by the LENGTH control. During playback, OUT A follows the drawn curve and OUT B follows the inverse of the curve. Both outputs have independent bipolar level controls, allowing flexible scaling and inversion.

Canvas Editing

The main display is the editable CV shape canvas. The horizontal axis represents time, while the vertical axis represents the normalized CV value. The shape is always stored internally between 0 and 1, and is scaled to voltage at the outputs using the LEVEL controls.

Edit Modes

The EDIT switch selects how the shape is edited.

• Draw: Drag freely to sketch the shape directly.
• Points: Add and move anchor points. Segments are straight lines.
• Curve: Add and move anchor points, and adjust curve handles to create smooth Bézier curves.

In Points and Curve modes, double-click an anchor point to delete it. The first and last points cannot be removed, as they define the start and end of the shape.

Controls

LENGTH sets the playback duration of the shape. The range covers very short transient shapes up to long evolving movements.

SMTH applies smoothing to the output voltage. Low values preserve sharp transitions. Higher values soften changes and can create more fluid modulation. For pitch use, keep smoothing low for accurate tracking.

LVL A sets the amplitude and polarity of OUT A.

LVL B sets the amplitude and polarity of OUT B. OUT B outputs the inverse of the curve, which can be further scaled or inverted using LEVEL B.

RST restores the default curve.

Inputs and Outputs

TRIG starts playback of the shape on a rising edge.

OUT A outputs the drawn curve.

OUT B outputs the inverted curve.

Visual Feedback

The moving playhead shows the current playback position. It is rendered as a single, stable vertical line for clear timing feedback, even at high speeds.

Typical Uses

• Custom filter sweeps
• Sidechain-style ducking
• Pitch envelopes and bends
• Opposing modulation between two targets
• Rhythmic CV patterns driven by triggers
• Smooth modulation with Curve mode
• Stepped or angular shapes with Points mode
• Fast sketching with Draw mode

Patch Ideas

Patch a clock or trigger source into TRIG. Send OUT A to filter cutoff and OUT B to a VCA. With opposite polarity settings, you can create dynamic push-pull motion between timbre and amplitude.

Use OUT A for pitch modulation with low LEVEL settings for subtle movement, or higher values for dramatic sweeps. Combine with low smoothing for precise shapes or higher smoothing for glide effects.

Drive F_DRAWCV with rhythmic triggers to turn the drawn shape into a repeating modulation groove.

Notes

F_DRAWCV is intended for control voltage, not audio-rate synthesis. For waveform drawing, use F_DRAWWAVE. For traditional envelopes, use F_MSEG. F_DRAWCV sits between those approaches as a flexible, drawable CV generator.

The bundle includes both a single-width and a double-width version. The single version saves space, while the double version offers more precision and easier editing.