SubDecay Vitruvian Mod




Ring modulation is a particularly mathy effect and challenging to describe. “Multiplying two signals creating sum and difference frequencies.” tells us little musically. Often cold, dissonant and conjuring  up whatever emotion it is that machines from the future feel. A rarely used effect, but you know it when you hear it. Carefully tuned ring modulator can create musical harmonic structures like Black Sabbath’s use on Paranoid. More often we hear them in science fiction films to make robots sound like evil emotionless killing machines.

Ring modulation with pitch detection

Sometimes you just want to plug in and play. The Vitruvian Mod pushes past the limitations of traditional ring modulation pedals with the pitch tracking power of a synthesizer. Inspired particularly by the usability of cross modulation. Dial in a setting and you don’t have to think about it, even if you change keys. You can even use it live and adjust by sight.

Fixed carrier modulation

Setting the tracking swtich to Null (0) gets you a traditional rind mod effect, but so much easier to dial in. With entropy set to “order”  The carrier knob has seven steps tuned to E A D G B E A. Perfect for guitar. The fine tune knob allows for further adjustment by +/- three semitones. Flip the entropy switch to “chaos” and the carrier has an eight octave range.

Using the Vitruvian Mod

We recommend using the Vitruvian Mod early in your signal chain. Running overdrives and fuzzes after the Vitruvian Mod can really bring out the effect’s harmonic structure. Add a wah pedal or filter after the Vitruvian Mod for synthesizer like effects. For leads try adding delay and modulation. Using a compressor in front of the Vitruvian Mod will add sustain.

Control Matrix

  • Entropy switch – Set to order for ease of use. Set to chaos for wider range.
  • Tracking switch – Set to HI or LO for tracking modes. Set to null (0) for fixed carrier mode.
  • Tracking knob (carrier) – Controls the internal carrier in seven fixed steps. Dependent on entropy and tracking switch settings.
  • Fine – Used to fine tune internal carrier dependent on entropy and tracking settings.
  • Mix – Adjust the amount of ring modulation. Turn to the left for fully clean. Turn to the right for fully modulated.
  • Volume – Overall output of the effect


  • Design- Brian Marshall, Tom Eddleman
  • Code- Tom Eddleman
  • Original pitch tracking algorithm developed by Don Stavely.

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fx pedal stompbox stomp box guitar effects pedal ringmod ring modulation ring modulator pitch/octave octaver frequency modulation modulate time-based lfo
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