ARP 2600 - ADSR Envelope Voltage Controlling the VCF; Demonstrating VCF Event Creation with ADSR

71
Resonance
2)
Square-wave
modulation will cause
the filter to alter-
nate
between two
F
c
's.
Careful
adjustment of
the mod-
ulation depth will set the higher
of these to any
partic-
ular frequency,
you choose. The lower
one will
remain
constant
at the initial
frequency setting
of the VCF
slider.
Just
for fun,
patch
the
VC02 square wave
into
the No.1 input to the voltage processor, the
processor
output (indicated
by
the panel
graphics)
into the
control
input
you've been
using on
the filter; note that now
the
modulation depth
affects
the lower of
the two frequen-
cies while
the
upper one remains
at the setting of
the
initial frequency slider.
It
will
be
worth while
to spend
a little time figuring out why
this happens;
refer
to 4.1
12
and
4.51
for assistance.
out
3)
Some sumptuous
natural vibrato
effects
can be created
by modulating
the filter
frequency with a
slow sine wave
say
around 6Hz—to a
very
slight depth. Use
an initial
F
c
two or
three
octaves above the
frequency
of the sig-
nal being
passed through
the
filter.
out