Osc 3 As A Low-Frequency Oscillator; The Noise Source; The Mixer - Moog MEMORYMOOG 345 Owner's And Service Manual

OSCILLATOR
3
AS A LOW-FREQUENCY OSCILLATOR
OSCILLATOR
3 differs
from
the other
two
oscillators
in
that
it
can
act
as
a
source of modulation
in
the
VOICE
MODULATION
section
(5.4).
For
this
reason
it's
useful to
be
able to use
OSCILLATOR
3 as
a
LOW-FREQUENCY OSCILLATOR
(LFO).
The
LOW
switch
(6.7)
converts the
oscillator
from
an audio
range
oscillator
to a iow-frequency
oscillator.
When
the
LOW
switch
is
turned on, the range of the
oscillator
drops by about
five
octaves.
If
you
leave the
MIXER
level
control for
OSCILLATOR
3 up,
youNI probably
hear
clicks.
That's because the
frequency of
the
oscillator
is
too low
to
be perceived
as pitch.
(For
more
on
the application of
OSCIL-
LATOR
3 as
an
LFO,
see
the section
on
VOICE MODULATION.)
Turning
the
KEYBOARD CONTROL
switch
(6.8)
off turns
OSCI
LLATOR
3 into a
drone
oscillator.
Without any
control voltage
from
the
keyboard
to
vary
its
pitch, the oscillator
will
remain
at
one
constant
pitch (unless
you modulate
it
with
some
other
voltage source
like
the
LFO). With
the
KEYBOARD
CON-
TROL
switch on,
OSCILLATOR
3
will
be controlled
by
the
keyboard
like
OSCILLATORS
1
and
2.
o
THE
NOISE
SOURCE
In
addition to the three audio
oscillators,
there are
two
other sound
sources
in
the
Memorymoog,
one
of
which
is
the
NOISE SOURCE,
whose
level
control
is
in
the
MIXER
(7.0).
The
noise
produced
\spink
noise, noise
weighted
to
produce
an equal
amount
of energy
in
each octave of the frequency spectrum.
It
has a
deep sound and
is
useful for creating
wind and
surf
effects.
The
other sound
source
is
the
VOLTAGE-
CONTROLLED
FILTER
which
is
discussed
later.
THE MIXER
The
MIXER
(7.0)
is
fairly straightforward.
Each
oscillator
and
the
NOISE
SOURCE
has
its
corres-
ponding
level
control that adjusts the
volume
of
its
output
signal as
it is
fed into the
FILTER. What may
not be
so
obvious
is
that
starting at
about 4
or 5
on
each
MIXER
control, clipping distortion
is
introduced.
This effect
enhances sounds by making them sound
audibly
larger
than
life.
For
a
diagram of
the
effects
of clipping distortion, see the section above on
the
oscillators.
o
OSCILLATORS
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30