Filter
A resonant low-pass filter for shaping tone.
AvailableEffect
Auto Filter
A low-pass filter driven by an LFO.
About
A low-pass filter swept by a free-running LFO, between a base frequency and a ceiling set in octaves above it. The rhythmic wah that does not care what you play.
Presets
Start from a named sound, then adjust the instrument to make it yours.
InitDefault
Signal graph.
ExperimentalA sketch of the signal path, in the order of the parameter groups.
How it works.
One LFO sweeps one low-pass filter. The LFO runs between the base frequency and the base frequency raised by Octaves, and Depth scales how much of that span it actually covers, so Base Freq sets where the sweep starts, Octaves sets how far it goes, and Depth sets how much of that distance is used.
The LFO is free-running: it is on its own clock and keeps cycling whether or not anything is playing. That is the entire distinction between this module and Auto Wah, which derives its motion from the input's level instead. Same filter, different thing moving it, and the two are not interchangeable in use.
The browser preview drives the filter's detune rather than its frequency, and that one choice is what makes the sweep musical. Detune is measured in cents, so a plain linear LFO on it produces an exponential glide, the same number of octaves per cycle whether the base is 50 Hz or 1500, with no shaping node and nothing recomputed per block. The LFO's gain is depth multiplied by octaves multiplied by 600, which is exactly the swing a unit sine needs to cover the named span peak to peak.
