Purpose

Synth is a polyphonic subtractive synthesizer for leads, pads, and bass. It provides band-limited oscillators (saw, square, triangle, sine), a Cytomic TPT state-variable filter with key tracking and envelope modulation, unison detuning, a sub oscillator, ADSR envelope, drive, and stereo spread.

TouchDesigner Use

Wire note_voices_f32_v1 from MIDI Note, a chord voicer, an arpeggiator, or any note-voice source into the voices input. Choose a waveform, set the filter, shape the envelope, and wire the stereo audio output to Device Out, an effect chain, or a mixer.

Inputs And Outputs

• Input 0: voices — note_voices_f32_v1 (required). Gate, pitch, velocity, and aftertouch per voice.
• Output 0: out — stereo audio (PCM f32).

Main Controls

• Waveform — Oscillator shape: saw, square, triangle, or sine. All shapes are band-limited with PolyBLEP anti-aliasing.
• Gain — Master output level.
• Unison — Number of detuned oscillators per voice (1-7).
• Detune — Unison detune spread in cents.
• Sub — Sub oscillator level (sine, one octave below the fundamental).
• Pulsewidth — Pulse width for the square waveform (0.05-0.95).
• Cutoff — Filter cutoff (0-1, mapped to 20 Hz-20 kHz logarithmically).
• Resonance — Filter Q (0-1, mapped to 0.5-20).
• Filtermode — Filter type: lowpass, highpass, bandpass, or notch.
• Filterenv — Filter envelope modulation amount (-1 to +1). Positive values open the filter on attack; negative values close it.
• Attack / Decay / Sustain / Release — ADSR envelope (milliseconds for A/D/R, 0-1 for sustain level).
• Drive — Post-filter saturation.
• Width — Stereo spread of unison voices.
• Keytrack — Filter cutoff key tracking amount (0-1). At 1.0, the filter follows the keyboard pitch.
• Limiter — Output safety limiter.

Notes

• Up to 8 polyphonic voices.
• The filter is a topology-preserving Cytomic SVF that remains stable at high resonance and fast modulation.
• Velocity controls output amplitude (30% floor + 70% velocity scaling).
• Glide between notes uses a simple exponential smoothing (5% per sample step).

Parameters

This operator does not expose user parameters in the extracted schema.

Catalog metadata

Roles

• transform
• generator
• instrument
• synthesizer

Tags

• subtractive
• polyblep
• unison
• filter
• svf
• adsr
• drive
• stereo
• note_voices

Search groups

• midi
• control
• audio
• music
• instrument
• synth