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CHAPTER 

4

Introduction

control). Another option you might 
like to have at your disposal is ran-
dom parameter control.

In the Virus, both of these tasks are 
executed by a so-called LFO (low 
frequency oscillator) that oscillates 
at frequencies below the audible 
range. An LFO is similar to the 
oscillators you have encountered 
thus far, but it oscillates signifi-
cantly slower so that its output 
signal is too low for human hear-
ing. So what good are they if you 
can’t hear them? LFOs are used in 
much the same manner as enve-
lopes, with the major difference 
that the are repeated indefinitely.

Start with the usual basic sound 
configuration or chose a modified 
sound to suit your taste. Locate the 
RATE pot in the LFO 1 section of  the 
control panel. The RATE pot is 
equipped with an LED that indi-
cates the speed of the LFO as well 
as its waveshape. Turn the RATE 
pot and check out how the flash of 
the LED indicates the change of 
pace as you rotate the pot.

Currently you are unable to hear 
the effect of the LFO as its modula-
tion intensity is set to 0 in the 
sound program.  In order to change 
this setting, you must access the 
AMOUNT button which works in 
conjunction with five vertically 
arrayed LEDs labeled OSC 1, OSC 2, 
PW 1+2, RESO 1+2 and ASSIGN: 
Press the AMOUNT button repeat-
edly and observe how the LEDs 
flash in succession (the LEDs OSC 1 
and OSC 2 flash separately as well 
as in unison). The corresponding 
modulation targets appear in the 
display, along with the modulation 
intensity values as determined by 
the VALUE pot and VALUE buttons. 
(You can also scroll through the