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Euclidean, Non Linear, Poly-metric, Polyrhythmic, Morph-able Step Sequencer

Roundels is uniquely based on summing the output of multiple Euclidean rhythm generators to produce new, hybrid rhythmic structures that feature both internal, small scale variation in addition to larger scale repetition. This, in combination with the natural variation provided by using the resultant poly-rhythms to drive a (non-fixed length) step sequencer, that can treat a sequence of notes as a Schoenbergian ‘pitch row’ or Fortean ‘set’, creates the possibility for effortless experimentation without resorting to stochastic intervention, thus giving the user ultimate choice in the direction of their music, and therefore ultimate control. The output of each of the Euclidean rhythm generators can be targeted to affect just the movement of the step sequencer (with no rhythmic trigger), to produce just a rhythmic trigger with no effect on changing the step sequencer’s position, or to affect both.

The step sequence of pitches can also be manipulated under transformational functions such as transposition, retrograde progression, intervallic inversion, diminution, and expansion, in addition to the standard re-ordering available in most sequencers of this type – backwards, forwards and ping-pong playback. It also includes variation of the step-size.

Roundels frees your sequences from being tied to the conventional timeline of a DAW’s sequencer. It can operate over any length of pulses and, using the external trigger function, can act in any time-world as it responds to MIDI note-on messages rather than clock pulses.

Roundels also features a unique sequence-morph function that brings together three discrete (user-generated) sequencer patches as one entity. This can be used manually, it can be auto- animated, or it can be controlled via your DAW’s automation.

Roundels is designed to function as a MIDIFX plugin in Logic.


Pitch Sequencer (1 – 21 steps):

  • Full 10 octave range per step.
  • Piano roll view for 1 and 2 octave range.
  • Multiple step patterns and pathways.
  • Per-step Mute and per-step Kill option.
  • Per-step Legato or per-step Ratchet function (each independently loop-able).
  • Total Sequence transpose (+/- 3 octaves).
  • Total Sequence pitch inversion (selectable inversion point).
  • Total Sequence compress or expand pitch range (selectable target pitch, + and – 1 octave down to single target pitch).
  • Chromatic Quantiser.

Independent Velocity Sequencer (1 – 8 steps):

  • Blend velocity with MIDI input function.
  • Compress velocity levels.
  • Swing function.
  • Adjustable gate length.
  • Humaniser.

Four independent, identical, Euclidean Rhythm Generators:

  • Summed output to step sequencer.
  • Selectable trigger function (off, pitch only, rhythm only, pitch & rhythm).
  • Adjustable length in pulses/beats – (1 – 34 pulses).
  • Adjustable triggers/steps – (1 – 33 triggers).
  • Rotate rhythm function (1 – 33 pulses).
  • Reverse rhythm function.
  • Invert rhythm function.
  • Half-speed function (x 16).

Output Viewer:

  • Rhythm and pitch-stream time-line viewer.
  • Adjustable range (2 – 96 x 16ths, 128, 192, 256 and 384 x 16ths).

Hard looping:

  • Entire sequence can be reset after a selectable length of pulses (1 – 96 x 16ths).

Sequence Morph:

  • Three independent sequence patches can be morphed together over time as smoothly as possible.
  • Morph can be manual, auto-animated, or controlled via automation.

Parameter Randomisation:

  • Individual sequences can be generated randomly.
  • Option to auto-generate a set of three random yet closely related roundels as a starting point.
  • Selectable targeting to randomise just the pitch content, the rhythmic elements, the sequencer settings, or all at once.

Single Sequence Usage:

  • All functions available to Automation.
  • Saving of presets via host application.
  • Sequencer is locked to host tempo 16ths BUT can be triggered by any stream of incoming MIDI Note Ons.
  • Using any tuplet pulse will result in poly-metric playback against that of the DAW in External mode.
  • Calculation of Lowest Common Multiple (in 16ths) for aggregated Euclidean rhythms.
  • Calculation of Lowest Common Multiple (in 16ths) for aggregated Euclidean rhythms and pitch sequence.
  • Selectable visual representation of summed Euclidean sequencers and pitch – (1 to 256 x 16ths).

Advanced Settings

Internal Sequencer:

  • Syncs with host tempo.

External Trigger:

  • Next-step triggered by incoming MIDI Note On.

FX Only:

  • Sequencer and velocity effects will act on incoming MIDI notes.
  • Quantiser, transpose, compress, invert, humanise, gate length, swing, velocity sequencer also active.

Add CC:

  • Sequencer can be used to merge a MIDI CC track with incoming MIDI notes.
  • Sequencer function operates broadly as it would generating pitch-content.

Arpeggiator 1:

  • Arpeggiator function transposing the entire sequence via incoming MIDI notes (in relation to Pitch 1).

Arpeggiator 2:

  • Spreads incoming chords out and sequences them according to user-settings of pitch sequencer and Euclidean rhythm generators.

[ Updated (04-07-23) Roundels version 1.01 ]:

  • Added Intel/Silicon Any Mac version.
  • Fixed some routines to lower overall CPU load.

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