Sequential PROPHET-600 - 7-4 MIXER; 7-5 FILTER

7-4 MIXKK
1
7
1
OSC A
a a
OSC
MIXER
Figure
7-4
MIXER
knob: Adjusts
the
ratio
of OSC A and OSC
B output
to
the FILTER.
7-5
FILTER
The FILTER module
contains controls for the filter itself
and for its ADSR envelope
generator.
The envelope generator is
discussed separately, below.
a
5
6
10
CUTOFF
10
RESONANCE
-
*
*
K*
10
ENVELOPE AMOUNT
EiO
tno
FULL
1/Z
OFF
Figure
7-5
CUTOFF knob: Adjusts cutoff frequency of
the 2k dB/octave (4-pole) low-pass filter.
It is rather like a tone
control. "Cutoff" is the frequency below which all elements of
the mixer's output
signal
are
let through- The higher-frequency
components
of
the
input signal (i.e. all those above the cutoff
frequency)
are
suppressed. The higher the
knob setting, the higher the frequencies are
which
pass
through the filter. Thus, the
"brighter" the sound.
RESONANCE knob: Adjusts the amount of filter resonance.
As the
setting
is increased
from
0,
the amount
of
resonance ("emphasis," "regeneration," or
"Q")
applied to
those
signal
components
at
the cutoff frequency will increase. As resonance increases,
frequencies lower than the cutoff will become
decreasingly audible in comparison with
those
nearer the cutoff. As the knob setting is
increased beyond 7, the filter breaks
into oscillation, acting
like
a
sine-wave audio source whose pitch is determined
by the
cutoff frequency.
ENVELOPE AMOUNT knob: The filter cutoff
may be contoured (shaped) electronically
according to a
voltage pattern provided by the envelope generator. The specific
envelope is
formed by the ATTACK, DECAY,
SUSTAIN,
and
RELEASE (ADSR) knobs.
The
ENVELOPE AMOUNT knob is an attenuator which sets the depth of the applied
envelope. If set to 0, the Filter
Envelope Generator will have no effect.
CM600A 12/82
7-5