Reference Manual
CHAPTER 20. LIVE AUDIO EFFECT REFERENCE 247
There are four different lter types: lowpass, highpass, bandpass and notch. For each type,
the X-Y controller adjusts frequency (to adjust, click and drag on the X-axis) and Q (also
called resonance; to adjust, click and drag on the Y-axis). You can also click on the Freq and
Q numeric displays and type in exact values.
Low Q values create a broad lter curve, while higher values introduce a narrow, resonant
peak to the sound. With bandpass ltering, Q sets the bandwidth of the passed signal.
The Quantize Beat control applies quantized modulation to the lter frequency. With Quan-
tize Beat off, frequency modulation follows the control source. Turning this feature on
updates the lter modulation rhythmically with stepped changes that track the master
tempo. The numbered buttons represent 16th notes, so, for example, selecting 4 as a
beat value produces a modulation change once per beat.
The Envelope section controls how the envelope modulation affects the lter frequency.
The Amount control denes the extent to which the envelope affects the lter frequency,
while the Attack control sets how the envelope responds to rising input signals. Low Attack
values cause a fast response to input levels; high values integrate any changes gradually,
creating a looser, slower response. Think of it as adding inertia to the response.
Lower Release values cause the envelope to respond more quickly to falling input signals.
Higher values extend the envelope's decay.
The Auto Filter also contains a Low Frequency Oscillator to modulate lter frequency in a
periodic fashion. The respective Amount control sets how much the LFO affects the lter.
The Rate control species the LFO speed. It can be set in terms of hertz, or synced to the
song tempo, allowing for controlled rhythmic ltering.
Available LFO waveform shapes are sine (creates smooth modulations with rounded peaks
and valleys), square, triangle, sawtooth up, sawtooth down, and sample and hold (generates
random positive and negative modulation values) in mono and stereo.
There are two LFOs, one for each stereo channel. The Phase and Offset controls dene the
relationship between these two LFOs.
Phase keeps both LFOs at the same frequency, but can set the two LFO waveforms out of
phase with each other, creating stereo movement. Set to 180, the LFO outputs are 180
degrees apart, so that when one LFO reaches its peak, the other is at its minimum.