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Chapter 6 Filter eects 12 4
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Boost A and Boost B knobs: Rotate to set the amount of boost—or cut—applied to the
frequency bands in lter bank A or B. You can use these knobs to compensate for the
reduction in volume caused by lowering the level of one or more bands. If you use Boost A
and Boost B to set the mix relationship between lter bank levels, you can use Fade AB (see
“Fade AB slider” below) to alter the tonal color, but not the levels.
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Slope pop-up menu: Choose the amount of lter attenuation applied to all lters in both lter
banks. You can choose 1, which sounds softer at 6 dB/octave, or 2, which sounds brighter at 12
dB/octave.
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Fade AB slider: Drag to crossfade between lter bank A and lter bank B. At the top position,
only bank A is audible, and at the bottom position, only bank B is audible. In the middle
position, the signals passing through both banks are evenly mixed.
EVOC 20 Filterbank modulation
The modulation section contains two LFOs. The Shift LFO parameters on the left side control
the Formant Shift parameter, and the Fade LFO parameters on the right side control the Fade
AB parameter.
Modulation parameters
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Shift LFO Intensity slider: Drag to set the amount of Formant Shift modulation by the Shift LFO.
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Rate knobs and elds: Rotate to set the speed of modulation. Values to the left are synchronized
with the host application tempo and include bar values, triplet values, and so on. Values to the
right are nonsynchronized, or free, and are displayed in hertz—cycles per second.
Note: The ability to use synchronous bar values could be used to perform a formant shift
every four bars on a cycled one-bar percussion part, for example. Alternatively, you could
perform the same formant shift on every eighth-note triplet within the same part. Either
method can generate interesting results.
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Waveform buttons: Click to set the waveform type used by the Shift LFO (left column) or the
Fade LFO (right column). You can choose from the following waveforms for each LFO:
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Triangle
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Falling and rising sawtooth
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Square up and down around zero (bipolar, good for trills)
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Square up from zero (unipolar, good for changing between two denable pitches)
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Random stepped waveform (S&H)
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Smoothed random waveform
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Fade LFO Intensity slider: Drag to control the amount of Fade AB modulation by the Fade LFO.
Tip: LFO modulations are the key to interesting eects. Set up either completely dierent or
complementary lter curves in both lter banks. You can use rhythmic material—such as a
drum loop—as an input signal, and set up tempo-synchronized modulations, with dierent
rates for each LFO. Also try inserting a tempo-synchronized delay eect—such as Tape
Delay—after the EVOC 20 Filterbank to produce unique polyrhythms.