Noise Engineering Tonnetz Sequent
Rhythm-driven triad generator using Neo-Riemannian Tonnetz transforms
8 HP Eurorack module
Tonnetz Sequent is a rhythm-to-triad generator based on Neo-Riemannian music theory. It maps gate inputs to the triadic transforms of the Eulerian Tonnetz, allowing rhythmic patterns to drive harmonic movement through triadic space. Three 1V/oct outputs provide Root, Third, and Fifth of the current triad, enabling three oscillators to play chords that evolve with each incoming gate. The Group knob and CV input apply dihedral rotation to the transforms, creating variant harmonic pathways beyond the canonical PLR operations.
Features
- Three independent 1V/oct pitch outputs (Root, Third, Fifth)
- Six gate-driven transform inputs based on Neo-Riemannian music theory
- Parallel (P), Leading-tone (L), and Relative (R) canonical transforms
- Mode input cycles through 6 triad pair types including augmented and diminished
- Home input resets to reference triad for the current mode pair
- Transpose input shifts all outputs up one semitone per trigger
- Group knob and CV input apply dihedral rotation to PLR transforms
- Modulo switch constrains all voices to a single octave
- Combined Trigger output fires 20ms pulse on any transform
- Four triad-type indicator LEDs (augmented, major, minor, diminished)
- Tune button unisons all outputs for oscillator calibration
- Compact 8HP form factor with 26mm depth
Controls & Jacks (18)
- Tune
- Group
- Aug LED
- Maj LED
- Min LED
- Dim LED
- P In
- L In
- R In
- M In
- H In
- T In
- Group CV In
- Modulo
- Trigger Out
- Root Out
- Third Out
- Fifth Out
How-To Guides
- Basic Chord Progression
- Evolving Harmonics with Group Modulation
- Explore Augmented and Diminished Triads
- Chromatic Drift Patch
- Polyrhythmic Chord Generator
Explore the interactive Tonnetz Sequent panel on BleepDex — tap any control to learn what it does.
