Access Virus Rack User Manual page 28

26 CHAPTER 4
Introduction
you might say many of the settings pro-
duce sounds reminiscent of stringed-
instruments; some sound picked, plucked
or snapped, others sound bowed.
For your next experiment set the ampli-
fier envelope so that you hear a constant
level when you press and hold a note.
Now deactivate the filter envelope by
setting the ENV AMOUNT to 0. Set Filter-
1Filter-1 to low pass mode and decrease
the filter frequency until you just barely
hear a muddy signal when you play
notes in the mid-range.
Now play a few higher and lower notes.
You will find that the lower notes have a
greater overtone content, whereas the
higher notes sound muddier and their
volume decreases until the notes are
completely inaudible. You might already
suspect what this is all about: As the
notes are transposed ever lower, more
portions of the signal fall below the cut-
off frequency, whereas with the notes
that are transposed ever higher, more
portions of the signal rise above the cut-
off frequency and subsequently are sup-
pressed until the root note and the last
audible portion of the signal is silenced.
To avoid this effect - or if desirable, to
amplify it - you have the option of influ-
encing the cutoff frequency via the pitch
of the note, i.e. the note number. The
degree of influence is determined by the
KEY FOLLOW parameter. You'll find this
parameter in the filter section using the
PARAMETER buttons just like you did in
FILTER 1 mode earlier on.
Please note that KEY FOLLOW is a so-
called bipolar parameter: Its control
range is not limited to the positive end
of the spectrum (0 to a maximum of
127). Bipolar controls effect negative val-
ues as well, in this case from the nega-
tive maximum of -64 through 0 an on to
the positive maximum of +63. Conse-
quently, if this value is set to the center
position (0) the pitch of the notes corre-
sponding to the keys on your keyboard
has no effect on the cutoff frequency. If
on the other hand you turn the KEY FOL-
LOW parameter clockwise towards the
positive control range, you will find that
the filter opens up increasingly as the
pitch increases with higher notes. At
lower notes, the filter closes down again.
If you turn the encoder counter-clock-
wise towards the negative control range,
the KEY FOLLOW effect is reversed.
With the Virus, you will encounter this
feature - intensity control via a bipolar
parameter - again in conjunction with
other modulation sources and targets.
Now experiment as much as you like
with different KEY FOLLOW settings and
tune the settings via the CUTOFF
encoder. And remember to bring all of
the other parameters you have encoun-
tered thus far into play.