The Noise Engineering Tonnetz Sequent is a triad generator module for use in Eurorack modular synthesizer systems. The module maps gate inputs to triadic transforms that allow for rhythmic stepping through triadic arrangements. The module outputs three 1/V8VA control voltages intended to control the pitches of oscillators. Three gate inputs govern the triadic morphing: there’s one for parallel, leading, and relative. There are additional inputs for transposing semitones, changing triad types, and resetting the triad. The Modulo switch snaps all the oscillators to a single octave, with all pitches falling outside the spectrum re-mapped to equivalents included in the octave’s range.
The module’s sets all the oscillators to the same pitch when depressed, offering a convenient means of tuning the oscillators. There’s also a gate output that functions as a trigger combiner by sending a signal every time a switch or gate transform input occurs.
Tonnetz Sequent Features
CV generated meant specifically for tonal chords and other triads
Outputs three different 1v/oct CV signals for use with other oscillators
LED indication for chord type: augmented, major, minor and diminished
Easily tunable with the Tune button, which locks all the outputs to the same voltage to sync the pitch of the three oscillators
The P, L, and R buttons move patterns in the Eularian Tonnetz. Each time you hit a button it will change the triad to a musically related triad.
Trigger inputs for modulating the P, L and R settings
To reset the sequence to the reference triad, hit the H button or trigger the H input.
Outputs for Root, third, and fifth scale degrees
P: Parallel Transform. When in the major mode. P moves the third down a semitone; when in minor P moves the third up a semitone.
L: Tone Exchange Transform. When in the major mode, L moves the root down a semitone; when in minor, L moves the fifth up a semitone.
R: Relative Transform. When in the major mode, R moves the fifth up a semitone; When in minor, R moves the root down a semitone.
M: Mode transform; changes which pair of triad sets that the transforms act upon. It switches between minor/major, major/augmented, augmented/major, major/minor, minor/diminished, diminished/minor and then back to the start.
H: Home transform; changes the current triad back to the reference triad for the current Mode pair.
T: Transpose transform. Transforms all notes of the triad one semitone up.