Auto Filter

Parameters

In the browser under MODULATION, beside the Chorus and the Flanger.

A resonant filter whose cutoff moves. Low-pass, high-pass, band-pass or notch, at 12 or 24 dB/oct; the cutoff is pushed up and down, in octaves, by an LFO and by an envelope that follows a level — the track's own, or another track's (a sidechain). The two add.

Controls and display

The filter. Band-pass peaks at 0 dB; notch removes a band. 24 dB/oct is twice as steep, with one resonant peak, not two stacked. Resonance is the peak at the cutoff: 0 is none, and it rises toward a whistle at 1.

The LFO. Rate in Hz, or with Sync on, once per Note locked to the song's tempo map — a "1/4" is a quarter note whatever the time signature, and it follows tempo changes and ramps. The square, the saws and the random level ease across their steps, so the cutoff never jumps. Phase turns where the cycle starts against the song; Stereo offsets the right channel's cycle, which is what moves a sweep across the stereo field.

The envelope opens the filter as the level rises (a negative amount closes it on a hit) and falls back at the Release. Its Trigger is the track it is on, or any other track: the hi-hats opening a pad's filter. A track has one trigger: a Duck and an Auto Filter on the same track listen to the same one, and picking a different one on either is refused with the reason.

What to reach for it for. Movement on a static part — a pad that breathes with the beat, a synth that opens over a bar — a filtered intro or breakdown, a wah on a guitar, a band-pass "telephone" vocal. It is a moving cut, not a tone fix (that is the EQ), and a deep sweep on a full mix reads as a mistake.

The agent may use it on tracks and groups, with Resonance capped at 0.3 and the LFO and the envelope at 3 octaves — it can add movement, not a whistle. Your own knobs go all the way.

The surface — THE SWEEP. Two cards. The sweep draws the filter at its knobs as one curve, with a dot on its corner. Drag the dot — in the device chain or the expanded view — sideways for the cutoff and up or down for the resonance, both at once, and the curve moves with it (Shift for fine). The shaded band is how far the LFO and the envelope reach. Its corner keys pick the type (LP · HP · BP · N for notch, spelled NOTCH in the expanded view) and the slope (12 · 24).

Movement draws one cycle of the LFO with a dot where it is, the shape keys (sine, triangle, saw up, saw down, square, random) and HZ · NOTE under it, the Trigger menu (own input, or any other track), and a bar showing the envelope's level. Every other setting is a knob under the cards. In the expanded device view the knobs move into the cards and a Cutoff now readout shows both channels' cutoff as it moves. Hover any part for what it is.