The Second Oscillator; Content - Access Virus Rack XL User Manual

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CHAPTER 5
Introduction
encoder from the sawtooth control range to-
wards the pulse control range, you are actually
dialing every other overtone out of the mix,
which explains why the sound becomes thinner.
You can continue modifying the sound by redu-
cing the symmetrical width of the pulse wave. In
the Virus, you can execute this sound-shaping
measure via the WAVE SEL/PW (PW = pulse
width) encoder, PROVIDED THE SHAPE PARA-
METER IS SET TO A POSITION IN THE NEGA-
TIVE HALF (RIGHT) OF ITS CONTROL RANGE.
Rotate the WAVE SEL/PW encoder slowly from
the left to the right and leave the SHAPE enco-
der at the far right position. You can hear how
the treble content of the sound increases while
the sound becomes ever thinner. At the far right
position, the signal is no longer audible becau-
se the pulse width is equivalent to 0% and con-
sequently the wave no longer oscillates.
Starting at the center position (12 o'clock) indi-
cated by the sawtooth, turn the SHAPE enco-
der counter-clockwise towards the left. You can
hear how the overtones are increasingly mixed
out of the signal until you can only hear the root
note. This sound is produced by a so-called si-
ne wave, one of 64 other waveshapes that you
have at your disposal for sound generation pur-
poses. These waveshapes can also be activa-
ted via WAVE SEL/PW (WAVE SEL: Wave
Select), PROVIDED THE SHAPE PARAMETER
IS SET TO A POSITIVE HALF (LEFT) OF ITS
C O N T R O L R A N G E ( E A R L I E R T H A N 1 2
O'CLOCK). Regardless of the current SHAPE
setting, you can also select a wave in the EDIT
menu under OSCILLATOR 1 WAVE.
Go ahead and check out the different wavesha-
pes. The second of the 64 waves is a triangle
wave, the remainder of the waveshapes are
each a unique tonal blend. After you have fami-
liarized yourself with this raw material, experi-
ment with the parameters of the FILTERS and
AMPLIFIER sections you have dealt with thus
far (don't forget about SATURATION and the
corresponding function of the OSC VOL para-
meter), to get a feel for how the diverse waves-
hapes respond to filtering, saturation and
amplifier modifications.
í

THE SECOND OSCILLATOR

As we mentioned previously, in addition to the
other sound sources, the Virus is equipped with
a second oscillator which has more sound-
shaping options than Oscillator 1.
Dial in the basic sound program that you had at
the very beginning; change the amplifier enve-
lope to suit your taste. In the sound program,
the OSC BAL (Oscillator Balance) parameter in
the OSCILLATOR menu is preset to the far left.
In order to hear Oscillator 2 in action, rotate the
Value encoder to the right. Towards the center
position (12 o'clock) you will hear how the tone
is modified and as you rotate the encoder fur-
ther to the right, how the intensity of this modifi-
cation is reduced. This effect is known as the
comb filtering effect. It occurs when two signals
with the same frequency but different phase
lengths are mixed. Press the same key on your
keyboard several times with the OSC BAL set
to the center position (12 o'clock). You should
notice that each note has a slightly different
tone. The oscillators are the source of this ef-
fect. The oscillators of the Virus oscillate freely,
consequently every time you play a note, the
phase constellation between the two oscillators
is different. For now, leave OSC BAL at the
center position (12 o'clock).