Filter Modulation - Access Virus Rack XL User Manual

- HIGHPASS the high pass filter which works
in the opposite manner of the low pass filter:
It suppresses the lower frequencies in a sig-
nal and lets the higher frequencies pass.
- BANDPASS the band pass filter which sup-
presses both ends of the tonal spectrum and
allows only a narrowly defined bandwidth of
the original sound to pass.
- BANDSTOP The band stop filter, band reject
filter or notch filter which works in the oppo-
site manner of the bandpass filter. It allows all
of the frequencies of a signal except for a nar-
row frequency band around the cutoff to
pass. The term "notch" is fairly descriptive;
you might say this filter chops a notch out of
the sound spectrum.
01111111111111111112
1 FILTER1
Mode Lowpass≤
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Now activate the different operating modes and
rotate the CUTOFF encoder to get a feel for the
way each filtering option works.
Along with the CUTOFF encoder, the RESO-
NANCE encoder is the most important control
feature of a filter. The filter resonance increases
the volume of the frequencies located near the
cutoff frequencies and suppresses the more re-
mote frequencies. This sound shaping feature
has a striking effect - especially when used in
conjunction with the low pass filter: it produces
a nasal or honking type of tone which increases
as you turn the resonance up. Experiment by
varying the RESONANCE setting in the different
operating modes in conjunction with different
CUTOFF settings. You will find the effect that
the RESONANCE encoder achieves is markedly
different for the band stop filter in comparison
to the effect it has on the other filter types: as
the resonance increases, the bandwidth of the
notch decreases; in other words more frequen-
cies on both sides of the filter frequency are al-
lowed to pass.
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FILTER MODULATION

Of course we don't want to require you to exe-
cute every sound modification manually by
twiddling encoders. All kinds of sound modifi-
cations in the Virus can be executed automati-
c a l l y m u c h i n t h e w a y o f y o u r p r e v i o u s
experiments with the volume controls: The am-
plifier envelope can be described as a variable
curve which, depending on the type and dura-
tion of attack, hold and release data, automati-
cally infl uences (tur ns it up or down) an
imaginary volume pot.
Similar procedures are applicable to the filter
frequencies. The FILTERS section features its
own envelope, the structure of which is identi-
cal to the amplifier envelope.
Like the aforementioned amplifier envelope, the
filter envelope is located in the ENV section. In
that section use the PARAMETER buttons to
select FILT ENV.
Much like the amplifier envelope, the filter enve-
lope automatically "rotates" the CUTOFF en-
c o d e r. H o w e v e r t h e r e i s o n e s i g n i fi c a n t
difference between the two envelopes. With the
amplifier envelope, you are always dealing with
an initial volume level of 0 because of course
you want absolute silence prior to the beginning
of a note. After the RELEASE phase, it is again
highly desirable that your box is silent. With the
filter envelope, the situation is somewhat differ-
ent: It always starts at the CUTOFF value that
PDF VERSION - RESTRICTIONS APPLY
ACCESS VIRUS RACK XL OS5
Filter Modulation
21