Microtonal pitch modulation using the step sequencer
In addition to the standard Step Sequencer functions outlined in the manual, enhancements in Surge 1.7 enable using it for quantizing the pitch of sequencer steps to degrees of loaded Scala SCL microtuning table files.
An initial consideration in configuring Step Sequencers for microtonal sequencing, is that there are actually two possible Pitch Modulation targets to assign Step Sequencer modulation-sources to:
Modulating Scene Pitch with one, or multiple, Step Sequencers is useful where one wants all three oscillators in a Scene to track the pitch in unison. With Scene Pitch modulation using more than one Step Sequencer, all of the modulation sources are summed to a single voice. Polyphonic input from a MIDI controller is still possible, but each voice contains the sum of all running Step Sequencers assigned to Scene Pitch.
With Oscillator Pitch modulation using the Step Sequencers, it is possible to route separate sequencers to each of the three available oscillators in a Scene. In this scenario, it becomes possible for the sequencers to trigger chords as the notes from each Step Sequencer play together.
Since the processes for routing Step Sequencer modulation-sources to either Scene Pitch or Oscillator Pitch are functionally identical, in this brief overview, we’ll focus on assigning Step Sequencers to Oscillator Pitch for microtonal pitch sequencing: