4.4 Filter section
DRIVE – This is the control to adjust the amount of extra gain to the oscillator audio signal
before it enters the filters. It can change the characteristics of the filter completely.
KEY – This is a bi-polar control that determines how the note played on the keyboard
affects the filter cut off frequency. At positive values above 0, higher note values will
increase the cut off frequency. At negative values below 0, higher note values will
decrease the cut off frequency.
CUTOFF – This is the cutoff control for the filter
RESO – The resonance of the filter
ENV – The filters envelope modulation amount. The values for the envelope itself can be
set in the ADSR controls in the filter section.
SOFT – The control for non linearity and saturation in the filter. If “soft” is activated, the
filter will sound more analogue and resonance will be less aggressive.
FILTER SELECTION BUTTON – This chooses the type of filters available in Saurus, these
include
I. 12dB Low Pass, a precise model of an analogue chamberlain filter with self oscillation and
non-linearity with a little feedback. It has character which is similar to the MS-20
II. 12dB High Pass, a precise model of an analogue chamberlain filter
III. 12dB Band Pass, a precise model of an analogue chamberlain filter
IV. 24dB Low Pass, a precise model of an analogue butterworth filter with self oscillation and
non linearity.
V. Notch filter
VI. Formant filter
FM – This determines the amount of Frequency Modulation (FM) applied to the filter.
FEEDBA. - This is the feedback control for the filter, it controls how much of the signal is
fed back into the filter.
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