Lowpass

Frequency: 0...164 — Sets the filter cutoff frequency over a range of more than 13 octaves. This control steps in semitones when turned slowly, but smoothly controls the filter without steps when turned at a faster rate.

4 Pole: On, Off — Selects the filter configuration. When on, the filter is in 4-pole mode. A 4-pole, low-pass filter rolls off frequencies above the cutoff frequency at a slope of -24dB/octave. When off, the filter is in 2-pole mode and has a slope of —12dB/octave and a more gradual roll-off of the higher frequencies.

Resonance: 0...127 — Emphasizes a narrow band of frequencies around the cutoff frequency. In 4-pole mode, high levels of resonance can cause the filter to self oscillate. In 2-pole mode, resonance is much more subtle.

Audio Mod: 0...127 — Controls the amount of audio from oscillator 1 used to modulate the filter cutoff frequency. For filter-only audio, set 1/2 Mix in the Oscillators section to 0/100, oscillator 2 Shape to Off, and oscillator 1 Shape to the desired waveshape. This is useful for bell-like FM sounds. A wide range of sounds can also be made using Audio Mod with the oscillators routed normally through the filter.

Key > Freq: 0...127 — Sets the amount of modulation from the note number — from either the beat, the pads, or via MIDI — to the filter frequency. Sometimes called key tracking in keyboard synths, because the cutoff frequency “tracks” notes played on the keyboard. A setting of 64 will step the filter in semitone increments for each successive note, 32 is quartertones, and so on.