Specifications

Chapter 84: Vacuum 459
As the control is moved left of center, the same
occurs, only the modulation is negative instead
of positive, so the effect is inverted.
Vacuum Mixer Controls
The Vacuum Mixer is where the signals from the
two oscillators are mixed together, their levels
balanced relative to one another. Also, an effect
called Ring Modulation can be added, and Drive
can be applied to the sum of both signals.
=
VTO 1 and VTO 2 Sets the relative volume of the
two oscillators. One (or even both) oscillators
can be reduced to silence, if needed.
Drive Adds a variable amount of distortion to
the mixed signal.
Ringmod Adds a variable amount of the VTO 1
and VTO 2 signals, multiplied together. This is
called Ring Modulation, and can create interest-
ing metallic or abrasive effects.
Vacuum Filter Controls
Vacuum features two separate filters, one a
high pass filter (HPF), the other a low pass filter
(LPF). The sound of each filter is affected by vol-
ume of incoming oscillator signals. Lower mixer
levels give the filters a clean response and a
sharper resonant peak. Increasing mixer gain
can overdrive the filters, adding character and
de-emphasizing resonance.
Each filter has its own set of controls.
Cutoff Sets the frequency at which the given fil-
ter begins to “cut off” part of the signal’s fre-
quency spectrum. In the HPF, frequencies below
the chosen frequency are affected. In the LPF,
frequencies above the chosen frequency are af-
fected.
Slope Sets the curve of the filter slope. At higher
settings, the slope is steeper, and more of the
spectrum is cut off. At lower Settings, the slope
is more shallow, and more of the spectrum is al-
lowed to pass.
Reso Affects the filter resonance, which is the
amount of signal fed back into the filter circuit
around the chosen frequency. At higher values,
a pronounced peak is created, which can range
from a subtle “edge,” all the way to a sine-wave-
like tone. At lower values, the filter simply cuts
off the specified frequencies.
Clicking the missing Drive knob will create a
new patch at random.
Mixer section
HPF controls