Filter Modulation - Access Virus Rack User Manual

FILTER MODULATION

Of course we don't want to require you
to execute every sound modification
manually by twiddling encoders. All
kinds of sound modifications in the Virus
can be executed automatically much in
the way of your previous experiments
with the volume controls: The amplifier
envelope can be described as a variable
curve which, depending on the type and
duration of attack, hold and release
data, automatically influences (turns it
up or down) an imaginary volume pot.
Similar procedures are applicable to the
filter frequencies. The FILTERS section
features its own envelope, the structure
of which is identical to the amplifier
envelope.
Like the aforementioned amplifier enve-
lope, the filter envelope is located in the
ENV section. In that section use the
PARAMETER buttons to select FILT ENV.
Much like the amplifier envelope, the fil-
ter envelope automatically "rotates" the
CUTOFF encoder. However there is one
significant difference between the two
envelopes. With the amplifier envelope,
you are always dealing with an initial
volume level of 0 because of course you
want absolute silence prior to the begin-
ning of a note. After the RELEASE phase,
it is again highly desirable that your box
is silent. With the filter envelope, the sit-
uation is somewhat different: It always
starts at the CUTOFF value that you
determined manually. And it is defi-
nitely not always desirable that the filter
frequency is brought to the maximum
level.
Consequently, you need a tool that limits
the effective range of the filter. This is
why we equipped the Virus with a con-
trol labeled ENV AMOUNT (short for
Envelope Amount). This encoder is posi-
toned in the Filter section. When the
encoder is turned counter-clockwise to
the far left, the filter has no effect on
the cutoff frequency; the further you
turn the encoder to the right, the
greater the effect the filter envelope has
on the filter frequency. The maximum
level of the envelope may lie outside the
audible range when the filter has
already been partially opened via the
CUTOFF encoder or was manipulated via
other control options. In extreme cases
where the filter is already completely
open, the filter frequency cannot be
increased regardless of how high you set
the ENV AMOUNT.
Go ahead and spend some experiment-
ing with different ENV AMOUNT, CUT-
OFF and RESONANCE settings for the
diverse filter operating modes. Also try
varying the settings for the amplifier
envelope. You will find that with just
these few parameters you are able to
come up with a vast amount of sound
settings. If you are among the many
musicians who are associative listeners,
ACCESS VIRUS RACK 25
Filter Modulation