Xaoc Devices BELGRAD Operator's Manual page 4

40
dB
20
0
-20
-40
-60
10 100
DuAL PEAK cOntROL
Unlike most traditional synthesizer filters
that offer just a single resonance (emphasis,
or Q) control, Belgrad is equipped with a
number of advanced resonance controls.
The overall degree of resonance is set by the
11
reso knob as well as a control voltage (0
to 8V) supplied to the reso input
two resonant peaks of the filter may have
different emphasis — set by the balance
13
knob — from domination of the lower
peak, through full symmetry, up to domina-
dB
20
XM
0
-20
OFF
-40
-60
SM
-80
-100
100
fig. 2
1000
12 . The
fig. 3
1000
tion of the higher peak (fig. 2). The degree of
symmetry may also be voltage controlled by
a bipolar (-5V to +5V) CV at the balance in-
14
put . Finally, the distance between the two
peaks is set by the span knob and CV from
zero up to nearly eight octaves.
sELf OsciLLAtiOn
& nOn LinEAR BEhAViOuR
With the reso knob set around 8 (depend-
Hz
ing on the mode and other settings), Belgrad
10000
starts to self-oscillate. In such state, it behaves
like one or two sine wave VCOs musically con-
trolled by the v·oct input. When tuned right,
it is expected to track about five octaves and
be reasonably stable with temperature vari-
ations.
Driving the resonance further reveals the
nonlinearities inherent in the feedback paths
of the filter cores, making the waveform more
saturated and distorted. Experimenting with
the balance and span controls can yield in-
teresting wave shapes.
Another unique feature that can produce
unusual sonic effects is the internal cou-
pling topology which applies double non-
linear audio-rate modulation to the filter
cores. It is controlled by the tito switch
and may be toggled from the neutral posi-
tion either up for self-modulation or down
for cross-modulation (fig. 3). The sm mode
gives the resonance a radical and textured
sound, while xm mode adds a warbly and
chirpy character in different scenarios such
Hz
as processing drums or bass.
10000
4
15