Dave Smith Instruments TEMPEST - Manual (Page 40)

30 Lowpass Dave Smith Instruments
Lowpass
Frequency: 0...164—Sets the filter
cutoff frequency over a range of
more than 13 octaves. This control
steps in semitones when turned
slowly, but smoothly controls the
filter without steps when turned at a
faster rate.
4 Pole: On, Off —Selects the filter configuration. When on, the filter is in 4-pole
mode. A 4-pole, low-pass filter rolls off frequencies above the cutoff frequency at
a slope of -24dB/octave. When off, the filter is in 2-pole mode and has a slope of
-12dB/octave and a more gradual roll-off of the higher frequencies.
Resonance: 0...127 —Emphasizes a narrow band of frequencies around the
cutoff frequency. In 4-pole mode, high levels of resonance can cause the filter to
self oscillate. In 2-pole mode, resonance is much more subtle.
Audio Mod: 0...127 —Controls the amount of audio from oscillator 1 used
to modulate the filter cutoff frequency. For filter-only audio, set 1/2 M
iX
in the
Oscillators section to 0/100, oscillator 2 Shape to Off, and oscillator 1 Shape to
the desired waveshape. This is useful for bell-like FM sounds. A wide range of
sounds can also be made using a
udio
M
od
with the oscillators routed normally
through the filter.
Key > Freq: 0...127 —Sets the amount of modulation from the note number—
from either the beat, the pads, or via MIDI—to the filter frequency. Sometimes
called key tracking in keyboard synths, because the cutoff frequency “tracks”
notes played on the keyboard. A setting of 64 will step the filter in semitone
increments for each successive note, 32 is quarter tones, and so on.