A filter removes part of the sound.
Low-pass keeps the bass and reduces the treble. High-pass keeps the treble and reduces the bass. Cutoff sets where that change begins.
Left = bass. Right = treble. The curve shows which frequencies get through.
Lower the cutoff to make the sound darker.
Where the filter starts removing frequencies.
Adds a peak near the cutoff. More = a ringing sound.
How far the cutoff moves. The diagonal-lined area shows its range. Zero = no movement.
Starting cutoff
Uses the cutoff you set in lesson 01. This lesson uses low-pass so moving right makes the sound brighter.
Time to move from the starting cutoff to its furthest point.
Time to settle from that point to the held level.
Level held while the note is pressed. This is a level, not a time.
Time to return to the starting cutoff after you let go.
Time to fade in from silence.
Time to settle from full volume to the held level.
Volume held while the note is pressed. This is a level, not a time.
Time to fade to silence after you let go.
The repeating path of the movement.
Repeats per second. 1 Hz = one cycle each second.
How far the chosen control moves. Zero = no movement.
What the LFO moves. Choose before playing.
Try one thing
Press Play Note and move Cutoff while it plays. Switch to High-pass and repeat. Listen for which part of the sound disappears.
On your OP-XY: M3 opens the filter. Dark gray adjusts cutoff; mid gray adjusts resonance. Shift + M3 selects a filter type.
Where do ladder and SVF fit?
Low-pass and high-pass describe what a filter does. Low-pass reduces high frequencies; high-pass reduces low frequencies.
Ladder and SVF describe how a filter is designed. A ladder filter links stages together, often giving a steep low-pass shape. SVF means state-variable filter: a design that can produce low-pass, high-pass, and band-pass responses. Band-pass keeps a middle band of frequencies.
These SVF and ladder examples are simplified working models, not copies of the OP-XY’s algorithms. On the OP-XY, compare the filter choices with the same sound and similar cutoff settings. Listen to the slope and the ringing as you raise resonance. Learn cutoff and resonance first; then explore each model’s character.
What does ADSR mean?
Attack → Decay → Sustain → Release. A note starts, settles, stays held, then ends. Attack, decay, and release are times. Sustain is the level held while you keep the note pressed.
The same shape can control different things: cutoff for the filter envelope, volume for the amp envelope.
How is an LFO different from an envelope?
An envelope follows a note through attack, decay, sustain, and release. An LFO repeats a wave over and over. Here the wave restarts with each note, like a triggered LFO.
This lesson uses a repeating wave as the source and three destinations. On your OP-XY, the Value LFO is a useful place to explore this idea. Other types add random, sensor-driven, or specialized movement.