The Synthesizer
24
The last parameter of the oscillator section is the VCF-drive. It produces an overload of the filter stage
which leads to those wonderfully distorted and aggressive overdrive-sounds. Each filter in the parts of
the Sirius therefore has its own distortion unit - very useful for, for instance, acid bass lines, aggressive
solo sounds etc.
For each of the 7 parts the Sirius has its own multi-mode-filter with controllable cut-off frequencies
and resonance (On the Sirius referred to as Q-factor). The cut-off frequency can be manipulated in a
number of ways. You can do this for instance with the separate envelope waveform generator which
generates sound changes automatically. You can also at any time "tune" the cutoff-frequency in real
time with the CUTOFF-control or assign it to the modulation wheel. Like all sound parameters the fil-
ter can also be controlled from an external Midi device.
The first three Keys in the filter section allow you to select one of the filter types. A low pass filter
(LPF) will only allow the frequencies below the cutoff-frequency to pass through. A high pass filter
(HPF) works the other way round. The frequency curve of the filter is given in dB/octave and de-
scribes how strongly the frequencies are faded in and out before and after the cutoff-point. The 12
dB filter is a milder curve than the steep 24 dB filter and therefore sounds a bit softer. The Key track
option is explained later.
Now choose a filter type with the Keys on the front-panel or use the VALUE/TEMPO-dial.
Edit Synt1-Sound
<9> VCFDrive: 27
Edit Synt1-Sound
<10> VCFTyp:LP24
The Filter-Section:
Q-FACTOR
VCF-EG
MACRO
LPF 24 dB
LPF 12 dB
HPF 12 dB
CUTOFF
ENV.-MOD
RESONANCE-FILTER
KEY-TRACKING
VCF-DYN.
f
dB
Filter without
resonance
CUTOFF-FREQ.
dB
f
Q-Factor
Sirius-Filter
with resonance
CUTOFF-FREQ.