Access virus os4 Manuale Utente

ACCESS VIRUS OS4

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 con-
trol panel, you have probably 
already gathered that it has more 
sound-shaping options than Oscil-
lator 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 pro-
gram, the OSC BAL (Oscillator Bal-
ance) 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 oscillators are 
the source of this effect. The oscil-
lators of the Virus oscillate freely, 
consequently every time you play a 
note, the phase constellation 
between the two oscillators is dif-
ferent. For now, leave the OSC BAL 
POT at the center position (12 
o’clock).

You are already familiar with Oscil-
lator 1’s SHAPE and WAVE SEL/PW 
pots. These functions are identical 
for Oscillator 2, so we won’t go into 
detail on them again.