Pure SUB’s Modulation Sidechain lets one modulation source control the depth of another, rather than directly moving an audio parameter. It changes how far an existing assignment travels while leaving that assignment’s underlying shape intact.
That is not the familiar setup where a kick feeds a compressor and ducks a bass channel. It requires no external audio and does not automatically reduce volume when drums hit.
Instead, it adds a second control layer to Pure SUB’s layered modulation system. One source can create movement, then another can govern how strongly that movement reaches its destination.
Modulation Sidechain makes that amount variable. The first source still supplies the curve, rhythm, or random behavior, while the sidechain source scales its influence. You get depth-controlled bass movement without redrawing the main modulator or duplicating its destination assignments.
This distinction matters when a patch needs a firm attack. If a Function drives a deep filter wobble from the instant each note begins, the opening transient can lose definition. An envelope controlling that Function’s depth can keep the first moment restrained, then allow wider movement as the note develops.
Reversing the envelope produces the opposite result. The bass can arrive with a pronounced sweep and settle into a steadier sustain, while the Function continues running. Its rate and waveform have not changed, only the amount reaching the filter.
Modulating the Function’s rate would produce a different result because the cycles themselves would accelerate or slow down. Sending the envelope directly to cutoff would add another independent movement. Sidechaining the assignment preserves one recognizable pattern and changes its reach.
The original modulation amount still defines the useful boundary. Set it too wide and a fully open sidechain can throw cutoff, pitch, or processing into an unusable range. Set that maximum first, then use the second source to move between restraint and the approved limit.
A Step Sequencer can provide that rhythm without receiving audio from the drum track. Assign it to layer level or another suitable destination, then let an envelope or performance control scale its depth. The sequencer supplies timing, while the sidechain decides how obvious the cuts become.
Velocity can make a related patch feel less mechanical. Harder notes can carry stronger filter or Morph movement while softer notes stay compact, provided velocity controls that modulation depth. The performance changes expression rather than merely raising volume.
Aftertouch, Mod Wheel, and MPE Slide offer manual versions of the same idea. A held note can begin stable, then gain deeper wobble or more Sub Processor movement under your fingers. Releasing the control returns the patch toward its original motion range instead of forcing the destination to one fixed value.
Random modulation also becomes easier to contain. Letting Random hit a filter or layer level directly can create abrupt changes across its full assignment range. Using it to scale a smoother Function preserves that Function’s contour while varying how far successive movements travel.
Layer-level movement can alternate clean weight and upper texture. Morph movement changes harmonic content without requiring the filter to do every tonal job, while Sub Processor modulation changes the intensity of a selected processing mode. Keeping those roles separate makes the sidechain source easier to tune.
Build the primary assignment before adding its controller. Confirm that its fastest rate and deepest setting remain useful across the notes in your part, then attach the sidechain source and reduce its range. Otherwise, two moving controls can hide whether the problem comes from the pattern or its changing depth.
Retrigger behavior also affects the result. A note-triggered envelope gives each note a repeatable modulation arc, while a tempo-synced Function or Step Sequencer may preserve the track’s rhythmic position. Short notes can expose only the restrained part of movement that becomes dramatic during sustained notes.
When one controller scales several related assignments, give each assignment its own safe maximum. The same envelope can open filter movement, raise texture variation, and increase processing intensity, but those destinations rarely need equal depth. Their separate limits determine whether the transformation stays coherent or collapses into uncontrolled motion.
That is not the familiar setup where a kick feeds a compressor and ducks a bass channel. It requires no external audio and does not automatically reduce volume when drums hit.
Instead, it adds a second control layer to Pure SUB’s layered modulation system. One source can create movement, then another can govern how strongly that movement reaches its destination.
Modulation depth becomes a moving target
Start with a simple assignment. A tempo-synced Function might sweep filter cutoff, or the Step Sequencer might push Sub Processor Amount through a rhythmic pattern. With a fixed modulation amount, every cycle covers the same range.Modulation Sidechain makes that amount variable. The first source still supplies the curve, rhythm, or random behavior, while the sidechain source scales its influence. You get depth-controlled bass movement without redrawing the main modulator or duplicating its destination assignments.
This distinction matters when a patch needs a firm attack. If a Function drives a deep filter wobble from the instant each note begins, the opening transient can lose definition. An envelope controlling that Function’s depth can keep the first moment restrained, then allow wider movement as the note develops.
Reversing the envelope produces the opposite result. The bass can arrive with a pronounced sweep and settle into a steadier sustain, while the Function continues running. Its rate and waveform have not changed, only the amount reaching the filter.
Modulating the Function’s rate would produce a different result because the cycles themselves would accelerate or slow down. Sending the envelope directly to cutoff would add another independent movement. Sidechaining the assignment preserves one recognizable pattern and changes its reach.
The original modulation amount still defines the useful boundary. Set it too wide and a fully open sidechain can throw cutoff, pitch, or processing into an unusable range. Set that maximum first, then use the second source to move between restraint and the approved limit.
This sidechain does not listen to the kick
Audio sidechain processing responds to another signal, commonly using kick level to control compression, gating, or an envelope follower. Pure SUB’s Modulation Sidechain instead connects internal control signals. It will not clear space for a kick unless you deliberately create suitable rhythmic movement inside the patch.A Step Sequencer can provide that rhythm without receiving audio from the drum track. Assign it to layer level or another suitable destination, then let an envelope or performance control scale its depth. The sequencer supplies timing, while the sidechain decides how obvious the cuts become.
Velocity can make a related patch feel less mechanical. Harder notes can carry stronger filter or Morph movement while softer notes stay compact, provided velocity controls that modulation depth. The performance changes expression rather than merely raising volume.
Aftertouch, Mod Wheel, and MPE Slide offer manual versions of the same idea. A held note can begin stable, then gain deeper wobble or more Sub Processor movement under your fingers. Releasing the control returns the patch toward its original motion range instead of forcing the destination to one fixed value.
Random modulation also becomes easier to contain. Letting Random hit a filter or layer level directly can create abrupt changes across its full assignment range. Using it to scale a smoother Function preserves that Function’s contour while varying how far successive movements travel.
Controlled movement starts with the destination
Filter cutoff is the obvious destination, but Pure SUB can also modulate layer levels, Harmonics Morph, and Sub Processor Amount. Each choice changes a different part of the bass, so linking all three at maximum depth usually creates less control, not more life.Layer-level movement can alternate clean weight and upper texture. Morph movement changes harmonic content without requiring the filter to do every tonal job, while Sub Processor modulation changes the intensity of a selected processing mode. Keeping those roles separate makes the sidechain source easier to tune.
Build the primary assignment before adding its controller. Confirm that its fastest rate and deepest setting remain useful across the notes in your part, then attach the sidechain source and reduce its range. Otherwise, two moving controls can hide whether the problem comes from the pattern or its changing depth.
Retrigger behavior also affects the result. A note-triggered envelope gives each note a repeatable modulation arc, while a tempo-synced Function or Step Sequencer may preserve the track’s rhythmic position. Short notes can expose only the restrained part of movement that becomes dramatic during sustained notes.
When one controller scales several related assignments, give each assignment its own safe maximum. The same envelope can open filter movement, raise texture variation, and increase processing intensity, but those destinations rarely need equal depth. Their separate limits determine whether the transformation stays coherent or collapses into uncontrolled motion.
