thorn.audio - Splines Vectoral Curve Generator [Black]

Splines is a visual vector curve generator with a wide frequency range, a built-in quantiser, CV scope and CV processing capability. It can be used in a similar way to a wavetable VCO, LFO, step sequencer or envelope generator and features a built-in quantiser. Settings can easily be saved, and the firmware updated, via USB. It’s a small, shallow, multifaceted addition to any setup and, for touring rigs, it can fulfil many roles while taking up minimal space and weight.

Features:

Splines are curved paths used in 3D modelling and animation. This module uses them as a 16-point sequencer where X = time and Y = voltage.

Each point triggers changes to the 1V/oct output when the phase (time) crosses it, with an optional gate trigger per point. The points are connected by a spline shaped by three parameters: Tension (curve intensity), Continuity (angle at each point), and Bias (shifts tension left or right).

Zoom and Scroll control which portion of the spline is output. Frequency sets the phase speed — from 16-minute LFO cycles up to 20kHz — and can be quantized using .scl scale files.

Level controls output amplitude, replacing the need for a dedicated VCA. When the signal exceeds ±5V, clipping options like wavefolding and soft clipping add further sound-shaping potential.

A rolling oscilloscope is built in for all six CV inputs, with scaling and offset controls.

The sync input is configurable for tap tempo, envelope, or sequencer-style timing.

A hardware expander — adding physical knobs for Tension, Continuity, Bias and Level, plus CV inputs for Scroll and Zoom — is due summer 2026.

Firmware and scales update via drag-and-drop over USB-C. Developer resources for ESP-32 DSP projects are included.

Inputs/outputs:
Output res.: 1-16 bits
Sample rate: 192kHz
Output voltage: +-5v
CV voltage range: +-5v
Trigger duration: 15ms
Input trigger: 5v