How to Restart a Phaser Sweep at the Same Position on Each MIDI Note

The moving part of a phaser is its filter pattern. For example, Kilohearts Phaser’s Cutoff control moves its spectral peaks and troughs; Rate controls the speed of its internal cutoff modulation, and Depth controls the extent of that movement. These are separate controls with separate jobs. Kilohearts — Phaser

For repeatable note attacks, the modulation must start at a chosen point each time. In Kilohearts’ LFO, Trigger restarts the cycle, Phase offsets its starting position, and Frequency determines its speed. Setting a rate alone leaves the trigger behavior unresolved. Kilohearts Docs — Modulation

Think of the desired behavior as a small instruction: whenever a note begins, return to this point in the modulation shape, then follow the shape at this speed. Keep that instruction in mind when evaluating controls with similar names.

Tempo sync determines how quickly a cycle runs relative to the song. Note retrigger determines when that cycle starts again. You may want both, but selecting a rhythmic rate does not establish a note-trigger connection.

A control labeled Phase can also mean something different from starting phase. In Ableton Live’s Phaser-Flanger, Phase changes the relationship between the left and right LFOs. Spin detunes their rates relative to each other. Neither description identifies a MIDI note reset. The device’s Center parameter sets the center frequency of the phaser notches. Ableton Live 12 Manual — Phaser-Flanger

Before changing settings, identify which of these tasks each control performs: setting sweep speed, choosing the initial modulation position, restarting modulation, or changing stereo movement. This prevents spending time adjusting stereo width when the missing element is a trigger.

With an existing playable Phase Plant patch, use a dedicated LFO to move a Phaser snapin’s Cutoff. The snapin is available inside Phase Plant as well as in standalone plugin form. Kilohearts — Phaser

1. Insert a Phaser snapin in the effect lane receiving your sound.
2. Set its internal Depth to zero, so the external LFO supplies the sweep.
3. Add an LFO in the bottom modulation lane and choose a simple triangle or sine shape.
4. Use the LFO’s plus icon to assign modulation to Phaser Cutoff. Adjust the modulation amount until the movement is easy to hear.
5. Set a fixed LFO Phase, then choose its speed in hertz or a synced note division.
6. Right-click the LFO’s Trigger button and select Always for note triggering.

The modulation assignment and LFO controls follow Kilohearts’ documented modulation system. Start with a modest sweep range, then enlarge it after confirming that notes restart the movement. Kilohearts Docs — Modulation

The explicit Always setting matters: Kilohearts documents that it triggers on every note-on. Legato triggers only at the beginning of an overlapping group, while Auto depends on voice settings and whether another modulator is attached to the trigger. For this task, choose Always rather than relying on Auto. The Power of Triggers in Kilohearts Host Plugins

Treat this as a starting recipe, not a preset specification. After the reset works, adjust the starting phase while repeatedly playing one note. Choose the position that gives the opening movement you want, then leave it fixed.

If you have Max for Live and Shaper MIDI available, you can generate a note-triggered sweep outside the phaser. The following setup is derived from Live’s documented mapping and phaser controls.

Place Shaper MIDI before the instrument and Phaser-Flanger after it. Select Phaser mode, turn the phaser’s Amount down to zero, and disable its envelope follower. Use Shaper MIDI’s Map button to target Center, so the drawn envelope supplies the frequency movement. Ableton Live 12 Manual — Phaser-Flanger

In Shaper MIDI, choose Remote Control, then set a useful Min–Max range. Draw a low–high–low shape for a complete sweep. Set Jitter, Velocity influence, and Echo to zero for the initial test. Choose the Rate, and enable Loop if the shape should repeat while the note is held. Shaper MIDI triggers its envelope with each MIDI note; Remote Control determines the mapped parameter’s value directly. Ableton Live 12 Manual — Shaper MIDI

Here, the first breakpoint establishes the opening position. You are drawing the sweep instead of resetting Phaser-Flanger’s internal oscillator. Keep the mapping range fairly narrow at first so you can hear the opening gesture clearly without an excessively wide frequency excursion.

There are two useful outcomes: one shared sweep that restarts whenever any note arrives, or an independent sweep for each sounding voice. Decide which you need before testing chords.

A shared phaser processes the combined sound. Consequently, restarting its sweep for a newly played note also changes the processing of notes already ringing. One shared frequency parameter cannot simultaneously follow two different sweep positions.

Phase Plant offers a specific route to independent processing: enable Poly on the lane containing the Phaser. Its manual states that polyphonic lanes process effects separately for each voice. Polyphonic lanes must be enabled in order from left to right; making lane 2 polyphonic also requires lane 1 to be polyphonic. Kilohearts Docs — Phase Plant, Effect Lanes

For a single-note phrase, a shared sweep may be exactly what you want. For staggered chord notes that should each retain their own opening gesture, use per-voice processing and check it with overlapping notes.

Use this listening test after completing either setup. It deliberately changes note spacing so an ongoing cycle is less likely to resemble a successful reset by coincidence.

1. Repeat the same pitch at the same velocity, leaving a gap between notes. Listen for the same opening direction and timing.
2. Move one note away from the regular rhythmic spacing. Its sweep should still begin at the chosen position.
3. Hold one note and play another before releasing it. Check whether the new note restarts the movement.
4. Hold a note long enough to hear what follows the opening sweep: repetition, a sustained position, or the end of the shape.
5. For a polyphonic setup, stagger two notes and listen for separate sweep trajectories.

For an illustrative timing example, a 2 Hz LFO completes a cycle in 0.5 seconds. Without retriggering, a note arriving 0.125 seconds later encounters the oscillator a quarter-cycle further on. With note retriggering, it begins from the selected start again. These are calculated example values, not plugin measurements.

Judge the modulation trajectory first. Changing pitch or changing the source sound makes an audible comparison harder, so keep those variables fixed during the initial test.

Work backward from the symptom instead of changing several controls at once.

Symptom	Next check
Gapped notes restart, but overlapping notes do not	Inspect Legato and note-trigger settings. In Kilohearts, use Always for every note-on.
The modulator restarts, but the phaser keeps wandering	Temporarily remove other modulation routes and confirm the phaser’s internal depth is zero.
The opening position repeats, but sweep size varies	Check velocity modulation; in Shaper MIDI, set Velocity to zero for the comparison.
A new note changes the sweep of an earlier note	Determine whether the effect is shared or processed per voice.
Manual triggering works, but played notes do not	Confirm that note events reach the modulator and that note triggering is enabled.

One particularly relevant Kilohearts detail: attaching another modulator to a trigger changes Auto behavior so notes no longer trigger it. An explicit Always selection avoids that dependency. The Power of Triggers in Kilohearts Host Plugins

Once the uneven-spacing and overlap tests behave as intended, save the patch with its trigger mode, starting position, sweep range, and shared or per-voice routing intact. You can then shape the phaser’s tone while preserving the repeatable note-opening movement you built.

• Phaser — Kilohearts
• Modulation — Kilohearts Docs
• The Power of Triggers in Kilohearts Host Plugins — Kilohearts
• Phase Plant — Kilohearts Docs
• Live Audio Effect Reference — Ableton Reference Manual Version 12
• Max for Live Devices — Ableton Reference Manual Version 12