The Second Filter - Access VIRUS CLASSIC User Manual

The Second Filter

You probably noticed that by a adding a bit of saturation to the signal you can come up with a pretty
heavy, aggressive sound - especially with a low filter frequency level and high resonance. You're
probably thinking these types of sounds could do with some more filtering. We had the same idea,
which is one of the reasons why we equipped the Virus with another filter per voice.
The technical design of this second filter is identical to the first, so we won't discuss it in as much
detail as we did the first filter. However, there are few differences in how you handle the second fil-
ter:
Only two control features of the Virus are allocated exclusively to Filter-2: CUTOFF 2 and FILT 2
MODE.
The RESONANCE, ENV AMOUNT and KEY FOLLOW pots can be allocated to either of the two fil-
ters or both simultaneously. Use the two SELECT buttons located at the far right of the FILTERS
section to select the desired operating mode. For instance, if you press the FILT 2 SELECT button,
then the values you set via the RESONANCE, ENV AMOUNT and KEY FOLLOW pots apply exclusi-
vely to Filter-2. The corresponding parameters of Filter-1 remain unaffected. On the other hand, if
you press both SELECT buttons at the same time, the values that you dial in apply by the same mea-
sure to Filters 1 and 2.
In the sound program we are using for our experiments, the LEDs of both buttons are illuminated, so
that all adjustments to the given parameters affect both filters. However, you have yet to actually
hear the effect of Filter-2 on the signal because it is mixed out of the audible signal path of the Virus.
Before we get started with our next experiment, deactivate SATURATION, set the ENV AMOUNT of
the filter envelope to zero and set CUTOFF 2 to the center position (12 o'clock) so that Filter-2
always has the same cutoff frequency as Filter-1 (we'll explain CUTOFF 2 a bit later). Set CUTOFF
to a medium or middle value and turn the RESONANCE pot counter-clockwise to the far left to
achieve a relatively muddy sound. Now locate the FILTER BALANCE pot at the upper right hand of
the control panel and rotate it from the left to the right. You will note the sound becomes muddier as
you turn the pot towards the center position (12 o'clock) and that the sound is somewhat brighter at
the far right of the control range then at the far left.
The reason for this effect is that when you turn the FILTER BALANCE pot to the far left, only Filter-1
is audible. When you rotate the pot to the right, Filter-2 is blended in so that it follows Filter-1 in the
signal chain. When you turn the FILTER BALANCE pot clockwise, Filter-1 is blended out of the sig-
nal chain until at the far right position only Filter-2 is active and audible.
Each filter in the Virus normally features 2 poles. However in the FILTER ROUTING operating mode
SER 6, Filter-1 operates with 4 poles, so the signal patched through Filter-1 (FILTER BALANCE to
the far left) is trimmed more drastically than when it is routed through Filter-2 (FILTER BALANCE to
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