Low-Pass Filter - Dave Smith Instruments Evolver Operation Manual

Note: If the Ring Mod amount is turned up, you will get output from the Oscillator
even if the Oscillator Level is set to zero.
Shape Seq: Off, Seq1...4 – This parameter allows sequencing Waveshapes. Off if
not in use, otherwise select one of the four sequences Seq 1, Seq 2, Seq3, or Seq 4
to change the waveshape on every sequence step. In other words, if sequence 1 is
selected, with step 1 = 10 and step 2 = 5, then waveshape 10 will play in the first step,
and waveshape 5 will play in the second.
Noise
Level: 0...100 – Controls the volume of white noise mixed into the filter. The same
amount goes into both channels.
External In
Level: 0...100 – Controls the volume of external audio input connected to the Left
and/or Right Audio Input jack on the rear of the Evolver Keyboard. There is a clip LED
to the right of the control to indicate clipping on the input signal.
Note: Use the Input Mode parameter in the Misc Params section to choose the
input mode.

Low-Pass Filter

The analog (real analog!) low-pass filter is actually two different filters; one for the Left
channel and one for the Right channel. This allows true stereo processing of external
audio signals run through Evolver. However, for simplicity and consistency the two
filters are normally driven together in tandem, so they normally respond the same
way.
Exceptions are when using the S
cutoff and resonance modulation destinations, which allow the two filters to be
modulated independently. Note that though they are normally controlled together,
since they are analog there will always be some subtle differences between the two
filters, which gives the Evolver a more natural sound.
4 Pole: – Selects either 2- or 4-pole operation for the filter. (The filter is in 4-pole
mode when the 4 P
Frequency: 0...164 – Sets the base filter cutoff frequency over more than 13 octaves.
There is special smoothing on the operation of the filter knob to eliminate stepping as
you turn the knob for clean manual filter sweeps.
Resonance: 0...100 – Sets the Resonance level of the filter. At high settings the filter
will self-oscillate in 4-pole mode. If the filter does not oscillate, make sure the 4 pole
switch is on.
Env Amount: -99...+99 – Sets the amount of filter envelope to the cutoff frequency.
This can be positive or negative, allowing inverted envelope control of the filter.
Velocity: 0...100 – Amount of key velocity controlling the level of the filter envelope.
Key Amount: 0...100 – Sets the amount of keyboard (MIDI note) to the filter cutoff. A
setting of 72 will step the filter one semitone for each MIDI note, 36 would be half-
semitones, and so on. Also, the MIDI note is derived using Oscillator 1 Glide, allowing
Glide tracking.
PLIT
switch is lit.)
OLE
parameter, and when using the separate filter
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