User Manual

27
Pro 3 User’s Guide
Filters
Filter Parameters (Front Panel)
Filter Type Buttons: Low-Pass 1, Low-Pass 2, State-Variable—These
select the lter type. Low-Pass 1 is a 4-pole, 24 db per-octave resonant
lter based on the Sequential Prophet-6. Low-Pass 2 is a classic 4-pole,
24 db per-octave ladder lter. State-Variable is a 2-pole, 12 db per-octave
lter based on the Sequential OB-6, with low-pass, notch, high-pass, and
band-pass modes.
Drive: 0...127—Increases signal input to the lter, boosting volume and
adding harmonic saturation and warmth.
Cutoff: 0...164—Sets the lter’s cutoff frequency.
Resonance: 0...255—Emphasizes a narrow band of frequencies around
the cutoff frequency. High levels of resonance can cause the Low-Pass 1
and Low-Pass 2 to self-oscillate and generate its own pitch. The State-
variable lter does not self oscillate at the maximum resonance setting.
High levels of resonance can sometimes cause the Pro 3 outputs to clip. To
remedy this, reduce oscillator levels in the Mixer, or reduce the Amp Envelope’s
amount parameter.
State: LP, Notch, HP, BP—This knob selects the State-Variable lter’s
mode of operation. It transitions smoothly from low-pass to notch to
high-pass operation, allowing a blending of these modes. Band-pass
operation is selected with the bp switch. Each lter mode has its own
characteristic sound and function. As noted previously:
• Low-pass: passes frequencies below the cutoff frequency
• Notch: removes frequencies in a notch centered around the cutoff frequency
• High-pass: passes frequencies above the cutoff frequency
• Bandpass: passes a band of frequencies centered around the cutoff frequency
On the front panel, band-pass mode is selectable only through the bp on/off
switch. However, you can actually smoothly transition between normal and band-pass
operation by choosing sem-normal-bp as a modulation destination in the mod matrix.
BP: On, Off—Switches the State-variable lter to band-pass mode.