15
numbered tones, i.e. the first (the root note that determines the pitch), third, fifth, and so forth. By
turning the SHAPE pot from the sawtooth control range towards 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 reducing 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) pot,
PROVIDED THE SHAPE POT IS SET TO A POSITION IN THE RIGHT HALF OF ITS CONTROL RANGE
(LATER THAN 12 O’CLOCK). Rotate the WAVE SEL/PW pot slowly from the left to the right and leave the
SHAPE pot 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 because the pulse
width is equivalent to 0% and consequently the wave no longer oscillates.
Starting at the center position (12 o’clock) indicated by the sawtooth, turn the SHAPE pot 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 sine wave, one of 64 other
waveshapes that you have at your disposal for sound generation purposes. These waveshapes can also
be activated via WAVE SEL/PW (WAVE SEL: Wave Select), PROVIDED THE SHAPE POT IS SET TO A
POSITION IN THE LEFT HALF OF ITS CONTROL RANGE (EARLIER THAN 12 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 waveshapes. The second of the 64 waves is a triangle wave, the
remainder of the waveshapes are each a unique tonal blend. After you have familiarized yourself with
this raw material, experiment 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 pot), to
get a feel for how the diverse waveshapes respond to filtering, saturation and amplifier modifications.
The Second Oscillator
As we mentioned previously, in addition to the other sound sources, the Virus is equipped with a second
oscillator. Judging from the amount of control features on this oscillator’s section of the control panel,
you have probably already gathered that it has more sound-shaping options than Oscillator 1.
Dial in the basic sound program that you had at the very beginning; change the amplifier envelope to
suit your taste. In the sound program, the
OSC BAL
(Oscillator Balance) pot in the MIXER section is
preset to the far left. In order to hear Oscillator 2 in action, rotate the OSC BAL (Oscillator Balance) pot
in the MIXER section to the right. Towards the center position (12 o’clock) you will hear how the tone is
modified and as you rotate the pot further to the right, how the intensity of this modification 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
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