Specifications

Audio Plug-Ins Guide274
An Envelope Follower tracks the loudness con-
tour, or envelope, of a sound. Think of it like
this: each time you play a note, the envelope
goes up and then down. The louder and harder
you play, the higher the envelope goes. In the
Moogerfooger Lowpass Filter, the Envelope Fol-
lower drives the cutoff frequency of the Lowpass
Filter. Since the envelope follows the dynamics
of the input, it “plays” the filter by sweeping it
up and down in response to the loudness of the
input signal.
Moogerfooger Lowpass Filter
Controls
Envelope Section
Amount The Amount knob determines how
much the envelope varies the filter. When the
knob is counterclockwise, the envelope signal
has no effect on the filter. When the knob is fully
clockwise, the envelope signal opens and closes
the filter over a range of five octaves.
Smooth/Fast The Smooth/Fast switch deter-
mines how closely the envelope tracks the loud-
ness of the input signal. Some sounds (like gui-
tar chords) have long, rough envelopes, and
often sound better with less dramatic changes in
the filter. Other sounds (like bass or snare
drum) are quick and sharp, and sound great
when the filter closely tracks their attack.
Mix The Mix control blends the original input
signal with the filtered signal. Use it to get any
mixture of filtered and unfiltered sound.
Filter Section
Control the filter using the Cutoff and Reso-
nance knobs and the 2-Pole/4-Pole switch.
Cutoff Cutoff opens and closes the filter. Turned
counterclockwise, fewer high frequencies pass
through the filter. Turned clockwise, more high
frequencies pass.
Resonance Resonance changes the way the filter
sounds. At low resonance, low frequencies come
through evenly. At high resonance, frequencies
near the cutoff frequency are boosted, creating a
whistling or vowel-type quality. When reso-
nance is maxed out, the filter oscillates and pro-
duces its own tone at the cutoff frequency. This
oscillation interacts with other tones as they go
through the filter, producing the signature
Moog sound.
Envelope
Time
Time
“Envelope”
of the sound
Audio waveform
of the sound
Audio waveform of a musical sound
Envelope signal of the same sound
The 2/4 pole switch selects the filter slope
Frequency
Gain
4-Pole
2-Pole