Access Virus Rack XL User Manual
ENGLISH VERSION
©1997-2002 Access Music GmbH, Germany.
This manual, as well as the software and hardware described in it, is furnished under licence
and may be used or copied only in accordance
with the terms of such licence. The content of
this manual is furnished for informational use
only, is subject to change without notice, and
should not be construed as a commitment by
Access Music GmbH. Access Music GmbH assumes no responsibility of liability of any errors
or inaccuracies that may appear in this book.
Except as permitted by such licence, no parts
of this publication may be reproduced, stored in
a retrieval system, or transmitted, in any form or
by any means, electronic, mechanical, recording, or otherwise, without the prior written permission of Access Music GmbH.
VIRUS is a trademark of Access Music GmbH.
All other trademarks contained herein are the
property of their respective owners. All features
and specifications subject to change without
notice.
Written by Christoph Kemper, Uwe G. Hönig,
Wiland Samolak and Marc Schlaile.
Translation by Thomas Green and Howard
Scarr.
http://www.access-music.de
info@access-music.de
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CHAPTER 2
Content
Content
IMPORTANT SAFETY REMARKS .............................. 8
Master Clock And Midi-Clock................................ 50
The Effects Section............................................... 51
Audio Inputs .........................................................51
Audio Routing.......................................................53
Sound Categories .................................................53
Additional Functions .............................................54
PROLOGUE
INTRODUCTION
THE VIRUS ........................................................... 16
The Amplifier Envelope ........................................ 18
The First Filter...................................................... 20
Filter Modulation .................................................. 21
The Saturation Stage ........................................... 23
The Second Filter................................................. 23
Filter Routing ....................................................... 25
The First Oscillator ............................................... 27
The Second Oscillator .......................................... 28
The Mixer Section ................................................ 30
The LFOs ............................................................. 30
Soft Knob 1/2....................................................... 33
Volume and panorama ......................................... 33
Velocity................................................................ 34
Unison Mode........................................................ 34
The Effects........................................................... 35
The Arpeggiator ................................................... 37
SoundDiver Virus ................................................. 37
More to Come ...................................................... 38
CONCEPT AND OPERATION
Operating Modes ................................................. 40
OPERATION.......................................................... 43
All About The Memory.......................................... 46
Random Patch Generator ..................................... 47
Modmatrix And Soft Knobs................................... 49
THE PARAMETERS
OSC SECTION (ENCODER) .....................................58
Oscillator 1...........................................................58
Oscillator 2...........................................................58
Oscillator 3...........................................................59
Sub Oscillator.......................................................60
OSC SEKTION (MENU)...........................................61
Oscillator 1...........................................................61
Oscillator 2...........................................................61
Oscillator 3...........................................................63
Oscillators ............................................................64
Ringmodulator...................................................... 64
Noise.................................................................... 65
FILTER SECTION (ENCODER) .................................66
FILTER SECTION/MENU......................................... 67
Filter 1.................................................................. 67
Filter 2.................................................................. 68
Filters................................................................... 68
ENVELOPE SECTION (ENCODER) ...........................72
Filter Envelope...................................................... 72
Amplifier Envelope................................................ 72
LFO SECTION (ENCODER) .....................................74
LFO 1 ...................................................................74
LFO 2 ...................................................................75
LFO 3 ...................................................................75
LFO SECTION (MENU) ...........................................77
LFO 1 ...................................................................77
LFO 2 ...................................................................78
LFO 3 ...................................................................80
EFX SECTION (ENCODER)...................................... 82
Reverb ................................................................. 82
Delay.................................................................... 84
Chorus .................................................................85
ACCESS VIRUS RACK XL OS5
5
Input .................................................................... 85
Analog Boost........................................................ 87
EFX SECTION/MENU............................................. 88
Delay/Reverb ....................................................... 88
Distortion ............................................................. 91
Phaser ................................................................. 92
Chorus................................................................. 93
Equalizer.............................................................. 94
Vocoder ............................................................... 94
EDIT SECTION/ENCODER...................................... 98
EDIT SECTION/MENU............................................ 99
Clock Tempo........................................................ 99
Common.............................................................. 99
Unison ............................................................... 102
Punch ................................................................ 103
Assign/Mod Matrix ............................................. 103
Velocity.............................................................. 106
ARPEGGIATOR&CTRL SECTION (ENCODER) ....... 108
ARPG&CTRL SECTION (MENU)............................ 110
Arpeggiator........................................................ 110
Categories ......................................................... 111
Second Output/Surround.................................... 111
THE MULTI MODE PARAMETERS
MULTIMODE PARAMETERS ................................ 114
The parameters of the Virus vocoder ..................131
Notes about the vocoder.....................................132
THE VIRUS AND SEQUENCERS
Parameter Control via MIDI .................................136
Organizational Information.................................. 136
Handling MIDI Parameter Control........................137
Notes on Adaptive Parameter Smoothing ............138
Problems Related to Parameter Control ..............139
Dump - The Sound in the Song........................... 140
TIPS, TRICKS& WORDS OF WISDOM
TIPS AND TRICKS ...............................................144
All abouts Inputs................................................. 145
About Effects......................................................145
Oscillators ..........................................................146
Filters................................................................. 147
Saturation for Added Grit and Dirt .......................147
LFOs .................................................................. 148
Volume Control...................................................150
Assign and the Soft Knobs..................................150
Arpeggiator ........................................................151
How to modulate the Vocoder parameters ..........151
MIDI ...................................................................152
The Operating System (OS)................................. 153
THE GLOBAL PARAMETERS
GLOBAL PARAMETERS/ SYSTEM SECTION ......... 120
Random Patch Generator ................................... 120
Input (Global) ..................................................... 120
MIDI................................................................... 122
System .............................................................. 125
THE VOCODER
Vocoder ............................................................. 130
APPENDIX
SYSTEM EXCLUSIVE DATA .................................158
System Exclusive Implementation....................... 158
Parameter Descriptions ......................................162
Multi Dump Table ...............................................174
Classes ..............................................................177
Mod Matrix Sources ..........................................179
Mod Matrix Destinations.....................................180
Soft Knob Destinations ......................................181
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CHAPTER 2
Content
MIDI Implementation Chart................................. 182
FCC Information (U.S.A)...................................... 184
FCC Information (CANADA) ................................. 184
Other Standards (Rest of World) ......................... 185
Declaration of Conformity................................... 186
Warranty............................................................ 187
Many thanks to .................................................. 187
INDEX
INDEX ................................................................ 190
ACCESS VIRUS RACK XL OS5
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CHAPTER 3
Important Safety Remarks
PLEASE READ AND HEED THE FOLLOWING
SAFETY GUIDELINES!
A few fundamental rules on handling electrical
devices follow.
Please read all notes carefully before you power
the device up.
SET-UP
Operate and store the device in enclosed
rooms only.
Never expose the device to a damp environ-
ment.
Never operate or store the device in extreme-
ly dusty or dirty environments.
CONNECTIONS
Be sure to use exclusively the included mains
power supply adapter.
Plug the device only into mains sockets that
are properly grounded in compliance with statutory regulations.
Never modify the included power cord. If its
plug does not fit the sockets you have available,
take it to a qualified electrician.
Always pull the power plug out of the mains
socket when you won’t be using the device for
prolonged periods.
Never touch the mains plug with wet hands.
Always pull the actual plug, never the cord,
when you’re unplugging the device.
OPERATION
Don’t set beverages or any other receptacle
containing liquids on the device.
Assure that air can circulate freely on all sides
of the device, especially when you mount it to a
rack.
Don’t set the device in the immediate vicinity
of heat sources such as radiators.
Don’t expose the device to direct sunlight.
Don’t expose the device to strong vibrations
and mechanical shocks.
Make sure the device is placed on a solid
base. Set it on a stable tabletop or mount it to a
rack.
Make sure that no foreign objects fall into or
somehow end up inside the device’s housing.
In the event that this should occur, switch the
device off and pull the power plug. Then get in
touch with an authorized dealer.
ACCESS VIRUS RACK XL OS5
9
Used on its own and in conjunction with
amps, loudspeakers or headphones, this device
is able to generate levels that can lead to irreversible hearing damage. For this reason, always operate it at a reasonable volume level.
MEMORY BATTERY CHANGE
The Virus stores its sound programs in a battery-buffered RAM. This battery (general type
designation: CR2032) should be replaced every
three to four years. The housing has to be
opened to change the battery, so take the device to a qualified service technician. Do your
part in protecting our environment and take it to
a shop that disposes of batteries properly.
Before you have the battery changed, save the
entire memory content of the RAM by loading it
to a sequencer via "Total Dump". Be advised
that RAM content is lost when the battery is
swapped. [“Midi Dump TX” on page 122]
CARE
Do not open the device, it is not equipped
with any user-serviceable parts. Repair and
maintenance may only be carried out by qualified specialists.
FITNESS FOR PURPOSE
This device is designed exclusively to generate
low-frequency audio signals for sound engineering-related purposes.
Any other use is not permitted and automatically invalidates the warranty extended by Access
Music Electronics GmbH.
Use only a dry, soft cloth or brush to clean the
device.
Do not use alcohol, solvents or similar chemi-
cals. These can damage the surface of the
housing.
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CHAPTER 3
Prologue
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CHAPTER 4
Prologue
Dear Virus Owner,
Congratulations on your choice, the new Virus.
You have purchased a cutting-edge synthesizer
that comes fully loaded with several revolutionary features. Here are just a few of the highlights:
The Virus delivers the sound characteristics and
tone of traditional analog synthesizers - for instance the Prophet 5 or Memorymoog to name
just two popular examples of the species - in a
previously unparalleled level of quality and handling ease. We’re not kidding, the Virus actual
delivers the authentic response of an analog
synth via a digital signal processor, although the
sound shaping and voicing options out-perform
those of it historical predecessors by a considerable margin.
The Virus comes with 1024 slots for storing
SINGLE sounds. These are organized in four
banks. The first two banks (A and B) are located
in the RAM, so you can overwrite them with
new sounds. The other two banks are ”hardwired”, i.e. they’re programmed into the FLASH
ROM.
The Virus rack XL offers a maximum of 32 voices. In Multi Mode, these are allocated dynamically to 16 simultaneously available sounds.
You have up to three audio oscillators plus one
suboscillator, a noise generator, a ring modulator, two Multi Mode filters, two envelopes, a
stereo VCA, three LFOs and a saturation stage
(SATURATOR) for cascade filtering, tube and
distortion effects.
The Virus offers a veritable number of effects.
Yo u have a powerful Chorus/Flanger section at
your disposal, as well as the Analog Boost - a
controllable bass emphasis, with each effect
available separately for every sound. Furthermore there is a 6-stage Phaser, and a patch
Distortion. You also get a global reverb/delay
unit that lets you create high-quality reverb effects and rhythmic delay taps. Delay time can
be synced up to MIDI clock.
With the benefit of two external audio inputs,
the Virus may also serve as an FX device and
signal processor that you can use creatively to
come up with all kinds of effects. External signals can be processed with filter, gate and lo-fi
effects, routed to the Virus effects section and
serve as a modulation source for frequency and
ring modulation.
Beyond that, you can use internal or external
signals as sources for the Virus’ on-board vocoder serve. The vocoder works with up to 32 filter bands and offers diverse manipulation and
modulation options.
You'll find parallel external audio inputs on the
front and back panel. You can determine the input sensitivity via a gain selector switch. You're
also free to activate a special Phono EQ that
enables you to connect a record player via a
suitable cord.
The up to three main oscillators produce 66
waveshapes, three of which are dynamically
mixable so that spectral effects are possible
within the confines of a single oscillator. In conventional synthesizers, this type of effect requires several oscillators. Synchronization,
frequency modulation and ring modulation between the audio oscillators delivers additional
complex spectral effects that you can use for all
kinds of sound shaping purposes.
The filters can be switched in series or in parallel within the voices via several options. When
you switch the filters in series, the saturation
stage is embedded between the filters. Consequently, an overdriven filter resonance can be
re-filtered within the same voice! A maximum of
six filter poles (36 dB slope!) enables radical
tonal manipulations.
ACCESS VIRUS RACK XL OS5
13
The LFOs feature 6 continuous variable waveshapes each, including a triangle with variable
symmetry and infinitely variable aperiodic oscillations for random variation of the controlled
parameters. The LFOs are capable of polyphonic as well as monophonic oscillation. In
other words, if several voices are active, the
LFOs can run independently or in sync. A
number of keyboard trigger options enable you
start LFO waveshapes with variable phase
lengths at the beginning of a note and/or to cycle once only, like an envelope.
Next to the numerous ”hard-wired” or fixed
modulation configurations, you can assign six
modulation sources to up to nine different modulation destinations via the Modulation Matrix.
For your modulation sources, you have LFOs,
velocity, the pitch bender, aftertouch, the modulation wheel, numerous MIDI controllers and
other sources to chose from. For your modulation destinations, you can select any sound parameter of the Virus that is conducive to being
remote controlled.
Up to 16 arpeggiators are available in MULTI
mode. These give you countless options for
creating arpeggios, which can also be synced
up to MIDI clock.
Sounds and effects are patched out via four audio outputs which of course can also be used to
route two stereo signals out.
The Virus rack XL comes with a powerful software editor for PC and Macintosh. It lets you
edit and manage sounds on a large-scale user
interface. You can access every sound parameter of the Virus rack XL directly via mouse click.
When you edit a parameter, the Virus will render
the changes immediately in real time. Accordingly, every parameter change that you make
using the encoder knobs (those knobs without
left and right control range limits) on the Virus
rack XL appears immediately on the screen. Incidentally, this editor is based on Emagic's popular SoundDiver.
In all modesty, we are especially proud of a feature we developed called Adaptive Parameter
Smoothing. For the first time in the history of
synthesizers equipped with memories, you can
manipulate a knob or control feature without an
audible step or increment. In other words, the
sound does not change abruptly but SEAMLESSLY. No more zipper noises! The Virus responds just as smoothly as analog synthesizers
did prior to the introduction of digital sound
storage.
And users of contemporary software sequencers will appreciate the fact that the Virus sends
all sound shaping commands immediately in
the form of MIDI Controller or Poly Pressure data (and of course accepts all of the corresponding Controller and SysEx messages). This
feature lets you dynamically control the Virus
and all its functions via computer.
Although far from complete, the features listed
above give you some indication that you now
own an exceptionally versatile, high-quality musical instrument that will give you plenty of joy
for years to come. We certainly hope you can
fully exploit the enormous potential of this fine
instrument.
Have fun and enjoy!
Your Virus Development Team
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CHAPTER 4
Prologue
Introduction
16
CHAPTER 5
Introduction
The Virus
This section provides deliberate, step-by-step
guidelines on operating and handling the Virus
for those of you who are new to the world of
synthesizers and MIDI. The following covers basics such as how to connect the Virus to an AC
power supply, your MIDI system and your audio
system. Then we will guide you through a series
of experiments designed to demonstrate the
different functional groups, their control features and the tasks they execute.
After you have finished reading this section, you
will be able to handle virtually all of the sound
generating and sound shaping functions of the
Virus. All of these are described in context.
Even the majority of less significant functions,
accessible via menus, are discussed here. You
will find a detailed, comprehensive description
of all functions of your new synthesizer in the
section following this introduction.
Please keep in mind that within confines of this
introduction, we are unable to impart all of the
knowledge and skills in acoustics, sound synthesis and MIDI control you might desire or
need to acquire. If you are keen to learn more
about these subjects, you should consider becoming a regular reader of one or several of the
leading trade publications in your country. Your
local musical instruments dealer or more experienced musicians will be able to recommend
the best magazines to you. And of course there
is a wide range of books available on these
subjects.
If you decide to read this section, we recommend you read it in its entirety from the start rather than begin with a subsection that is of
particular interest to you. A fitting metaphor for
the basics discussed in this section might be a
house where each bit of information in a sub-
section is a brick that builds on a preceding
brick and interlocks with those next to it. You
want your knowledge base to be a sound structure so you won’t run into problems when you
find one of the “bricks” is missing.
CABLE CONNECTIONS
Before you connect the Virus to an AC outlet
and the rest of your equipment, ensure that all
of the devices are switched OFF. If your Virus
does not have a build-in keyboard, then connect the MIDI OUT of the desired MIDI send device (keyboard, computer, hardware sequencer,
etc.) with the MIDI IN of the Virus.
Connect the audio outputs of the Virus with the
signal inputs of your audio system. In order to
receive a signal, as a minimum you must connect the output OUT 1 R/MONO. However, we
recommend you also connect the output OUT 1
L so you are able to enjoy the stereo sounds of
the Virus.
Once you have established the desired cable
connections, make sure the main volume controls of all the connected devices are dialed to
the lowest possible setting. Switch the devices
on in the following sequence: the MIDI send device (computer, master keyboard, etc.) first,
then the sound generators (Virus and the other
signal sources), followed by the mixing console
and finally the amplifier.
POWER UP THE VIRUS RACK XL
Power up the Virus rack XL by pressing the
POWER button. To shut the device down, press
and hold this button for approx. two seconds.
Now while you are sending notes on MIDI
Channel 1 of the Virus, turn the master volumes
of the connected devices up in the same order
that you switched the devices on. Be sure to
keep on eye on the signal level indicators of
your mixing console.
LISTENING TO THE FACTORY SOUNDS
The program memory of the Virus was loaded
with sound programs (SINGLE PROGRAMs)
and sound combinations (MULTI PROGRAMs)
before it left the factory. To hear the SINGLE
PROGRAMs (and gain an initial impression of
the possibilities your new instrument has to offer in terms of sounds), first make sure your
MIDI source is sending on MIDI Channel 1.
Press the SINGLE button. A number, a letter,
number and name appear in the display. These
indicate the the MIDI Channel, the current Program Bank (A to H) as well as the number and
name of the current sound program.
Now if you play notes you should be able to
hear this sound and a quarter note (the round
dot at the end of the note staff is solid black)
should appear in the display every time you
press a key and release a key. If you do not hear
a sound but you see a half note (blank note
head) check to see if you are sending on the
wrong MIDI Channel.
Press the VALUE button to call up the 128 single programs of Bank A in sequence. (The VALUE encoder is inactive in this operating mode.)
In order to hear the sound programs in banks B
to H, simply use the PARAMETER/BANK buttons to step from one program bank to another.
You’ll find that some sound programs are labeled with the abbreviations ”INP” or ”VOC”.
These use the external audio input as a signal
source for the filter section (INP) or vocoder
(VOC). This means that you won’t hear anything
until you route an audio signal into the external
audio inputs.
ACCESS VIRUS RACK XL OS5
LISTENING TO THE MULTI PROGRAMS
The Virus not only has the capability of playing
SINGLE PROGAMs, but also combinations
consisting of more than one sound simultaneously (MIDI Multi Mode). To call up the MULTI
PROGRAMs, press the MULTI button and select these combination programs via the VALUE
button. The Virus features “only” 128 MULTI
PROGRAMs, so you don’t have to switch back
and forth between banks they way you just did
while activating single programs.
The majority of available MULTI PROGRAMs
contain sound combinations that are controlled
via a single MIDI channel. In these MULTI PROGRAMs, the sounds involved are allocated
side-by-side (split) or on top of one another
(layered) on the keyboard. In other MULTI PROGRAMs, the sounds are divided up over several
MIDI channels to make it easier to work with a
sequencer. If you activate a MULTI PROGRAM
and hear a single sound only, then you can control this MULTI PROGRAM via several channels.
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CHAPTER 5
Introduction
SOUND CATEGORIES
To help you find the type of SINGLE sound you
are looking for more quickly, the Virus operating
system lets you define so-called „categories“
and save this information together with each of
your SINGLE sounds.
Each SINGLE sound can „belong“ to two categories at the same time. Of course the categories of all the presets in Banks C to H are fixed,
but for sounds in the RAM Banks (A and B) they
can be defined and saved together with the
program.
To search for sounds in a specific category (in
SINGLE or MULTI-SINGLE mode):
Press and hold the SINGLE button. This causes
the currently selected category to appear in the
display, and it can be changed by stepping up
or down with the Parameter buttons. Having
found the category you want, do not release the
SINGLE button and scroll through the sounds
using the Value buttons. Release the SINGLE
button when you have found what you are looking for. SINGLE sounds which do not belong
to the currently selected category are simply
skipped over.
should end abruptly. This sound is not designed
to be especially pleasant; it is intended to be as
neutral as possible to give you a basis from
which you can begin creating or shaping your
own sound.
THE AMPLIFIER ENVELOPE
Long-term exposure to this sound will definitely
grate on your nerves, so let’s get started with
changing it into a signal you might enjoy hearing, beginning with the volume characteristics.
Locate the two vertically arrayed buttons next
to the seven LEDs. Use these UP and DOWN
buttons to select from among the seven parameter groups and/or sections. The appropriate
LED lights up to indicate that the given section
has been selected. Select the ENV section. The
labels on the five encoder knobs for this section
read ATTACK, DECAY, SUSTAIN, SUS TIME and
RELEASE.
YOUR FIRST SOUND PROGRAM
If you have never created or changed a sound
on a synthesizer, we now have the pleasure of
introducing you to this fascinating process.
Press the button
program “A127 - START -” by using the
buttons. Press any key on the connected keyboard. You should hear a sound that, for lack of
better description, is a bit harsh or biting, but
above all completely static. It should start immediately after you press a key and sustain indefinitely for as long as you hold the key down.
As soon as you release the key, the sound
SINGLE
and select the single
VALUE
These controls will help you to dial in volume
characteristics called an amplifier envelope and
put an end to the nerve-racking drone that may
remind you of one of those cheesy organs that
you hear in ‘60s B-movie sound tracks.
The section labeled ENV addresses the envelope. On a synthesizer, an envelope is used to
modulate sound over time. The Virus has two
envelopes, one for volume (AMP ENV) and one
for the filters (FILT ENV), which we will learn more about later. The five encoder knobs serve to
shape either the amplifier envelope or the filter
envelope. Make sure that you can see AMP
ENV in the display, and not FILT ENV. If this is
not the case, use the PARAMETER buttons to
set the section to the amplifier envelope.
ACCESS VIRUS RACK XL OS5
The Amplifier Envelope
Whenever the SUSTAIN level is set to maximum, the volume cannot drop during the DECAY phase; in other words, in this situation the
DECAY encoder is ineffective.
The individual functions of a synthesizer are
designed to interact; many functions are dependent on other functions. In a number of cases this means that some functions are
subordinate to others, i.e. the effectiveness of a
control feature is altered, modified or even negated completely by other related functions.
19
Rotate the ATTACK encoder while you repeatedly engage a key to hear the note. The further
you turn the encoder up, the longer it takes for
the sound to achieve maximum volume after
the start of the note. So you can say ATTACK
controls the initial volume swell of the sound.
Take a look at the display of the Virus to gain an
impression of the difference between these two
values. It shows two numeric values when you
dial a encoder: at the left you can see the value
stored in the sound program and at the right,
the numeric equivalent to the value determined
by the current position of the encoder.
Now fiddle with the DECAY encoder while you
repeatedly press a key to activate a note. Hold
the key down for good while. You will notice
that the volume, once it reaches maximum level
at the end of the ATTACK phase, drops until it
reaches a minimum level. The DECAY encoder
determines the speed, or in synthesizer jargon,
the rate at which the volume decreases.
However, the DECAY level does not always
drop to the minimum level; you can determine a
random value between the maximum and minimum levels at which the volume remains constant. This level in turn is controlled via the
SUSTAIN encoder.
The final encoder, RELEASE, determines the
speed or rate at which the volume decreases
when you release the key: At low values the
sound ends relatively abruptly, at high values,
the sound fades out more gradually and softly.
The length of the RELEASE phase also depends on which level the amplifier curve is at
when you release the key: The lower the level,
the shorter the RELEASE phase. If you dialed in
a brief DECAY or SUSTAIN-TIME phase and it
ended while you held the key down then of
course there will not be an audible RELEASE
phase.
The next phase of the amplifier envelope is determined by the SUSTAIN-TIME encoder: If the
encoder is set to the center position, then the
SUSTAIN level remains constant through to the
end of the note.
If you turn it counter-clockwise to the left, then
the level drops off at an increasing rate towards
the minimum level much in the manner you just
experienced with the DECAY encoder; If you
turn the encoder clockwise to the right, the level
rises at an increasing rate to maximum and
remains there until you release the key.
T he amplifier envelope can be described as a
variable curve which, depending on the type
and duration of attack, hold and release data,
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20
CHAPTER 5
Introduction
automatically influences an imaginary volume
encoder (turns it up or down). At the beginning
of the note, ATTACK controls the rise or rate of
increase to the maximum level. Once the maximum level is achieved, DECAY determines the
fall or rate of decrease to the SUSTAIN value,
which is infinitely variable between the minimum and maximum levels. The amplifier envelope may remain at this value until the end of
the note, fall towards the minimum level as determined by the variable TIME value, or even rise again towards the maximum level. After the
end of the note, RELEASE controls the fall or
Now we will take a look at a component of a
synthesizer that is generally regarded as the
most important functional unit as it enables drastic sound shaping measures: the filter - or in
the case of the Virus, the two filters.
But first we will concentrate on just one of the
two filters.
rate of decrease to the minimum level. Consequently, the control encoders labeled ATTACK,
DECAY, TIME and RELEASE control a speed or
rate, where as SUSTAIN actually controls a level.
THE FIRST FILTER
most pronounced, adjust the amplifier envelope
so that the Virus generates a constant level while you hold a key down).
This is how a low pass filter works: it suppresses, or in technical jargon, attenuates the higher
frequencies in a signal and allows the lower frequencies through. Think of the CUTOFF encoder as a bouncer and the Virus as your pub. You
can tell it which frequencies to let in and which
frequencies to keep out. The frequencies above
the so-called cutoff or filter frequency are suppressed, those below it remain unaffected.
Use the UP or DOWN buttons to activate the filter section FILT. The second encoder knob in
this row is labeled CUTOFF (not to be confused
with CUTOFF 2!). Rotate the encoder to the left
and right and note how the sound becomes
muddier and clearer in response to the direction
in which you turn the encoder. (To ensure this
effect and the following aural experiments are
Now we'll look at a parameter that is not assigned a dedicated knob of its own, but can be
dialed up in the display. This type of parameter
may be selected via the PARAMETER buttons
and then adjusted with the VALUE knob or the
VALUE buttons.
Select the FILTER 1 Mode parameter via the
PARAMETER buttons. To do this, make sure
that the display is still in the filter section FILT.
This parameter enables you to select a filter
operating mode from the four available options:
- LOWPASS
discussed.
the low pass filter we have just
ACCESS VIRUS RACK XL OS5
Filter Modulation
21
- HIGHPASS
in the opposite manner of the low pass filter:
It suppresses the lower frequencies in a signal and lets the higher frequencies pass.
- BANDPASS
presses both ends of the tonal spectrum and
allows only a narrowly defined bandwidth of
the original sound to pass.
- BANDSTOP
filter or notch filter which works in the opposite manner of the bandpass filter. It allows all
of the frequencies of a signal except for a narrow 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
the high pass filter which works
the band pass filter which sup-
The band stop filter, band reject
1 FILTER1
Mode Lowpass≤
61111111111111111154
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 RESONANCE 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 remote 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 frequencies on both sides of the filter frequency are allowed to pass.
FILTER MODULATION
Of course we don’t want to require you to execute every sound modification manually by
twiddling encoders. All kinds of sound modifications in the Virus can be executed automatically much in the way of your previous
experiments with the volume controls: The amplifier envelope can be described as a variable
curve which, depending on the type and duration of attack, hold and release data, automatically influences (turns 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 identical 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 envelope automatically “rotates” the CUTOFF encoder. However there is one significant
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 different: It always starts at the CUTOFF value that
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22
CHAPTER 5
Introduction
you determined manually. And it is definitely
not always desirable that the filter frequency is
brought to the maximum level.
Consequently, you need a tool that limits the effective range of the filter. This is why we
equipped the Virus with a control labeled ENV
AMOUNT (short for Envelope Amount). This encoder is positoned in the Filter section. When
the encoder is turned counter-clockwise to the
far left, the filter has no effect on the cutoff frequency; the further you turn the encoder to the
right, the greater the effect the filter envelope
has on the filter frequency. The maximum level
of the envelope may lie outside the audible
range when the filter has already been partially
opened via the CUTOFF encoder or was manipulated via other control options. In extreme cases where the filter is already completely open,
the filter frequency cannot be increased regardless of how high you set the ENV AMOUNT.
Go ahead and spend some experimenting with
different ENV AMOUNT, CUTOFF and RESONANCE settings for the diverse filter operating
modes. Also try varying the settings for the amplifier envelope. You will find that with just these
few parameters you are able to come up with a
vast amount of sound settings. If you are
among the many musicians who are associative
listeners, you might say many of the settings
produce sounds reminiscent of stringed-instruments; some sound picked, plucked or
snapped, others sound bowed.
For your next experiment set the amplifier envelope so that you hear a constant level when you
press and hold a note. Now deactivate the filter
envelope by setting the ENV AMOUNT to 0. Set
Filter-1Filter-1 to low pass mode and decrease
the filter frequency until you just barely hear a
muddy signal when you play notes in the midrange.
Now play a few higher and lower notes. You will
find that the lower notes have a greater overtone content, whereas the higher notes sound
muddier and their volume decreases until the
notes are completely inaudible. You might already suspect what this is all about: As the
notes are transposed ever lower, more portions
of the signal fall below the cutoff frequency,
whereas with the notes that are transposed ever higher, more portions of the signal rise above
the cutoff frequency and subsequently are suppressed until the root note and the last audible
portion of the signal is silenced.
To avoid this effect - or if desirable, to amplify it
- you have the option of influencing the cutoff
frequency via the pitch of the note, i.e. the note
number. The degree of influence is determined
by the KEY FOLLOW parameter. You'll find this
parameter in the filter section using the PARAMETER buttons just like you did in FILTER 1
mode earlier on.
Please note that KEY FOLLOW is a so-called
bipolar parameter: Its control range is not limited to the positive end of the spectrum (0 to a
maximum of 127). Bipolar controls effect negative values as well, in this case from the negative maximum of -64 through 0 an on to the
positive maximum of +63. Consequently, if this
value is set to the center position (0) the pitch of
the notes corresponding to the keys on your
keyboard has no effect on the cutoff frequency.
If on the other hand you turn the KEY FOLLOW
parameter clockwise towards the positive control range, you will find that the filter opens up
increasingly as the pitch increases with higher
notes. At lower notes, the filter closes down
again. If you turn the encoder counter-clockwise towards the negative control range, the
KEY FOLLOW effect is reversed. With the Virus,
you will encounter this feature - intensity control
via a bipolar parameter - again in conjunction
with other modulation sources and targets.
ACCESS VIRUS RACK XL OS5
The Saturation Stage
23
Now experiment as much as you like with different KEY FOLLOW settings and tune the settings via the CUTOFF encoder. And remember
to bring all of the other parameters you have
encountered thus far into play.
THE SATURATION STAGE
In the signal chain of the Virus, Filter-1 is followed by a saturation stage. It enables you to
add overtones to the filtered signal via distortion. Locate the parameter SATURATION in the
FILTERS section.
01111111111111111112
1 SATURATION
Curve Off≤
61111111111111111154
The display will read ”SATURATION CURVE
OFF”, which means exactly what it says. With
the VALUE buttons or the VALUE encoder, you
can now select from a number of saturation/distortion curves.
At this point we would like to mention the OSC
VOL parameter, which is next to the SATURATION parameter. The portion of the control
range from the far left to the center position (0)
determines the volume of the filter section’s input signal. The portion of the control range located to the right of the center position does
not achieve any increase in volume; it simply
intensifies the degree of saturation or distortion.
This effect is only achieved when you have activated a saturation curve.
Feel free to experiment with the diverse satura-
tion curves and be sure to vary the OSC VOL
settings. Note how the different CUTOFF and
RESONANCE settings influence the saturation
curve.
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.
Yo u’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 filter:
A Only two parameters of the Virus are allocated exclusively to Filter-2: CUTOFF 2 and FILT 2
MODE.
A The RESONANCE, ENV AMOUNT and KEY
FOLLOW parameters can be allocated to either
of the two filters or both simultaneously. Use
the FILTER SELECT menu in the FILTERS section to select the desired operating mode. For
instance, if you choose FILT2, then the values
you set with RESONANCE, ENV AMOUNT and
KEY FOLLOW apply exclusively to Filter-2. The
corresponding parameters of Filter 1 remain unaffected. On the other hand, if you choose
FILT1+2, the values that you dial in apply by the
same measure to Filters 1 and 2.
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24 CHAPTER 5
Introduction
In the sound program we are using for our experiments, both filters are selected, 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 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 encoder counter-clockwise to the far
left to achieve a relatively muddy sound.
Now locate the FILTER BALANCE parameter in
the FILT menu and rotate it from the left to the
right. You will note the sound becomes muddier
as you turn the encoder towards the center position 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 to the far left, only Filter1 is audible. When you rotate the parameter to
the right, Filter-2 is blended in so that it follows
Filter-1 in the signal chain. When you turn the
FILTER BALANCE clockwise, Filter-1 is blended
out of the signal 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 the far right). When you
set the FILTER BALANCE to the center position
(12 o’clock) - as we mentioned before - the two
filters are routed in series, which means they respond as if they were a single filter with 6 poles
and consequently a great deal of slope. This is
why the input signal is trimmed substantially
when you set the parameter to this position.
Experiment with the diverse FILTER BALANCE
values to get a feel for the different degrees of
slope. Rotate the CUTOFF encoder or activate
the filter envelope (for both filters!) to hear the
filters in action.
The CUTOFF 2 parameter is a special feature: It
controls the cutoff frequency of the second filter, but is subordinate to the CUTOFF encoder
located above it. In other words, at the center
position (12 o’clock) the manually selected frequency of Filter-2 is identical to that of Filter-1.
When you rotate the encoder to the left the cutoff frequency level of Filter-2 is increased relatively to Filter-1, when you turn to encoder to
the right the cutoff frequency level is decreased
relatively. Now when you adjust the CUTOFF,
you adjust the cutoff frequency of both filters by
the same measure! This feature lets you determine a difference in values in the filter frequencies (called an offset) via the CUTOFF2 encoder
which remains constant whenever you adjust
the CUTOFF encoder.
Yet another experiment in which you can come
up with new filtering characteristics that are
typical of the Virus:
Set FILTER BALANCE to the center position
(12 o’clock) and CUTOFF 2 to the maximum
level. The FILTER ROUTING operating mode
must remain SER 6. Set CUTOFF and RESONANCE to a middle value and select a clearly
audible SATURATION curve.
Now you can filter this complex signal produced by a combination of the saturation stage
and the Filter-1 yet again. Rotate the CUTOFF 2
encoder slowly towards the center position (12
o’clock). You can hear how Filter-2 gradually
modifies the distorted signal. You can set a
RESONANCE value for Filter-2 if you choose
ACCESS VIRUS RACK XL OS5 25
Filter Routing
FILT 2 in the FILTERS SELECT menu and rotate
the RESONANCE encoder to the desired position. Set the CUTOFF 2 encoder to a position to
the right of the center position. This configuration can be described as a complex non-linear
filter set up where the cutoff frequency is controlled via the CUTOFF encoder. You can dial in
a wide range of sound-shaping option via CUTOFF 2. Also try modifying the resonances of
both filters as well as the SATURATION curve to
come up with different filtering characteristics.
Now experiment with the diverse filter modes
and listen closely to the effect of the parameters RESONANCE, ENV AMOUNT and KEY
FOLLOW in conjunction with FILTERS SELECT.
Please also keep in mind that the chances of
choking a sound off are substantially greater
when you are using both filters: For instance, if
the first filter is used as a low pass with a low
cutoff frequency and the second as a high pass
with a high cutoff frequency, the Virus will not
generate an audible signal when you set FILTER BALANCE to the center position (12
o’clock).
- SER-6 The filters are switched in series; Filter-1 has four poles (24dB/Okt.), Filter-2 has
two poles (12dB/Okt.) so the overall slope is
equivalent to six poles (36dB/Okt.).
- PAR-4 The filters are switched in parallel and
feature two poles each (12dB/Okt.).
- SPLIT The filters are switched in parallel and
feature two poles each (12dB/Okt.). Additionally, they receive independent input signals (more
on this later). Each of the two oscillators routes
its signal into one of the two filters whose signals can be spread in the panorama via a parameter called UNISON Pan Spread.
Regardless of which FILTER ROUTING op-
tion you chose, the SATURATION stage is always post-Filter-1, i.e. after Filter in the signal
chain.
FILTER ROUTING
The final parameter we’ll discuss for the time
being is FILTER ROUTING. This feature offers
several filter routing options which allow you to
operate the filters in series, i.e. patch one after
the other in the signal chain, or in parallel, which
means side by side in the signal chain:
- SER-4 The filters are switched in series; with
two poles each (12dB/Okt.), both filters have
the same slope for a total of four filter poles
(24dB/Okt.).
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26 CHAPTER 5
Introduction
Her is the filter routings capabilities of the Virus.
THE FIRST OSCILLATOR
ACCESS VIRUS RACK XL OS5 27
The First Oscillator
To this point, we have turned our attention exclusively to sound-shaping functions and have
always started with the same basic material: a
so-called sawtooth wave. This waveshape is
especially well-suited as a neutral starting point
as it contains all of the so-called natural scale of
overtones, which give the filter plenty of quality
material to work with.
The filters, with the exception of a notch filter or
band stop (BS), trim the far reaches of the tonal
spectrum, so for instance a signal sounds muddier after it has been routed through a low pass
filter. You can well imagine that this type of
sound modification is substantial but insufficient for shaping more subtle differences in tone. For instance the tone of a trumpet differs
significantly from that of a saxophone even
though no one would seriously claim that either
of the instruments has a muddier tone than the
other.
What you need is a sound-shaping option for
the portion of a signal that a filter allows to
pass. And of course you also need a tool for determining the pitch of a signal. In synthesizers,
both of these tasks are executed by oscillators.
They oscillate at a variable pitch that can be
modulated and they also generate different waveshapes which give the filters a wider variety
of material to work with.
The Virus is equipped with two main oscillators
and a so-called suboscillator. We will first take a
look at Oscillator 1, which is the oscillator you
have already heard in action during your experiments thus far.
Dial in the same basic sound that you started
with at the very beginning (A127 - START -). To
this end, first press the SINGLE button in order
to return to Play mode from the selected parameter section. In Play mode, you can switch
sounds via the VALUE buttons.
Now modify the amplifier envelope so you are
working with a less grating sound, but hold
back on any other filter or saturation modifications so you can hear the purest oscillator signal
possible.
Locate the section labeled “1”, it is bordered off
in a separate area at the far left of the section
labeled OSCILLATORS. No check out the two
encoders labeled SHAPE and WAVE SEL/PW.
These enable you determine the waveshape
and consequently the tonal spectrum of Oscillator 1.
In the sound program, SHAPE is preset to the
center position. The display shows “Saw” for
the sawtooth waveform.
Press and hold a key and slowly turn the encoder clockwise. You should be able to hear how
the tone becomes increasingly more hollow-sounding. You might say this effect thins the
sound out, but in any case, the entire tonal
spectrum is affected by an equal measure,
which is an audio result filters are unable to
achieve.
The waveshape that is audible when you turn
the SHAPE encoder to the far right is a so-called pulse wave. It is unique because the duration of the negative pulse is equal to the duration
of the positive pulse: It has a so-called pulse
width of 50%. The tone of a pulse wave is different to that of a sawtooth wave because it does
not contain all overtones in the natural overtone
scale, only the odd-numbered tones, i.e. the
first (the root note that determines the pitch),
third, fifth, and so forth. By turning the SHAPE
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28 CHAPTER 5
Introduction
encoder 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) encoder, PROVIDED THE SHAPE PARAMETER IS SET TO A POSITION IN THE NEGATIVE HALF (RIGHT) OF ITS CONTROL RANGE.
Rotate the WAVE SEL/PW encoder slowly from
the left to the right and leave the SHAPE encoder 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 encoder 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 PARAMETER
IS SET TO A POSITIVE HALF (LEFT) 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 parameter), 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 which has more soundshaping 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) parameter in
the OSCILLATOR menu is preset to the far left.
In order to hear Oscillator 2 in action, rotate the
Value encoder to the right. Towards the center
position (12 o’clock) you will hear how the tone
is modified and as you rotate the encoder 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 oscillators of the Virus oscillate freely,
consequently every time you play a note, the
phase constellation between the two oscillators
is different. For now, leave OSC BAL at the
center position (12 o’clock).
ACCESS VIRUS RACK XL OS5 29
The Second Oscillator
You are already familiar with Oscillator 1’s
SHAPE and WAVE SEL/PW parameters. These
functions are identical for Oscillator 2, so we
won’t go into detail on them again.
Locate the encoder labeled DETUNE and slowly rotate it to the right from the far left position
(which is preset in the sound program). You can
hear the tone start to waver and as you turn the
encoder further to the right, how this vibrato effect increases until Oscillator 2 sounds distinctly out of tune with Oscillator 1. This wavering or
vibrato-type effect has a popular traditional in
synthesizers. It is used to achieve chorus effects, create sounds reminiscent of stringed instruments/ string sections or simply beef up the
sound.
The SEMITONE encoder enables you to transpose Oscillator 2 by plus/minus four octaves in
semitone steps while Oscillator 1 maintains the
pitch. This feature is especially interesting when
used in conjunction with two other oscillator
functions: synchronization and frequency modulation.
Locate and activate the SYNC parameter in the
OSCILLATOR 2 menu (Sync On). The synchronization function forces Oscillator 2 to restart its
wave cycle at the same time as Oscillator 1
waveshape starts its cycle. The initial effect of
this measure is that the wavering tone that resulted from detuning and mixing the oscillator
signals disappears.
The other effect that benefits from manipulating
the interval between the oscillators is frequency
modulation (FM). It generates new tonal spectra
in which the signal of the first oscillator controls
the frequency of the second oscillator similar to
the manner in which filters can be controlled via
envelopes. And here too you have a encoder
which allows you to control the intensity of: FM
AMOUNT. Basically, this effect is similar to a vibrato, although here you’re dealing with an extremely fast vibrato featuring a frequency within
the range of human hearing. This signal is not
actually audible as a vibrato effect. Instead,
you’ll hear a sound modulation, in some cases,
a very drastic one at that. Choose the pure sine
waveshape for Oscillator 2. In conjunction with
the sine wave, the frequency modulation generates very clear, in some cases bell-like, spectra.
In the Virus you have the option of combining
the two functions called oscillator synchronization (SYNC) and frequency modulation (FM
AMOUNT, to generate new harmonic spectra.
Switch SYNC on and experiment with the FM
AMOUNT. Also try out different SEMITONE settings and the diverse waveshapes of Oscillator.
The Virus is equipped with a third master oscillator that lets you create further oscillations and
spectra. You can access the parameters of this
oscillator, which are described in a later chapter, via the OSCILLATOR EDIT menu.
The SYNC effect really becomes interesting
when you transpose Oscillator 2 upwards in
comparison to Oscillator 1 via the SEMITONE
encoder. What happens is that the wave cycle
of Oscillator 2 is interrupted as soon as Oscillator 1 starts its cycle. The pitch of the second
oscillator no longer has the expected effect, instead it generates special tones, in some cases
for lack of a better description “screaming” type
effects.
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30 CHAPTER 5
Introduction
THE MIXER SECTION
You have already come across two parameters
of the MIXER section: OSC BAL determines the
mix ratio between Oscillators 1 and 2; in the left
half of its control range, OSC VOL determines
the master volume of the oscillator mix. In the
right half of the control range from the center
position to the far right, OSC VOL increases the
saturation intensity when a SATURATION curve
has been activated.
Now we’ll take a closer look at the SUB OSC
parameter: It controls the volume of the third
oscillator, the so-called SubOscillator, which always operates an octave below Oscillator 1.
The SubOscillator is mixed to the Oscillator 1
and 2 master mix signal as determined by the
OSC BAL parameter. The master volume of the
composite mix is controlled by the OSC VOL
parameter. The only other parameter available
for the SubOscillator is accessible via the OSCILLATOR EDIT menu where you have the option of selecting a triangle or pulse waveshape
(SUB OSCILLATOR WAVE SQUARE/TRIANGLE).
Another voice-internal signal source of the Virus
is the Noise Generator (NOISE Volume). Please
keep in mind that the level of the Noise Generator is not subject to the master volume controlled by the OSC VOL parameter. In other words,
it is audible even when OSC VOL is set to zero.
The VIRUS’ ring modulator is a new sound
source. The output of the two oscillators is multiplied to create interesting sounds with rich en-
harmonic overtones. These overtones are highly
dependent on the frequency coherence of both
oscillators and it’s waveforms. The frequency
coherence can be changed, for instance use
the OSC2 SEMITONE parameter. To blend in
the ring modulator use EDIT: RINGMODULATOR VOLUME (in OSCILLATOR EDIT Menu). If
the RINGMODULATOR VOLUME is zero, the
ring modulator is switched off. OSC VOL does
not affect the ring modulator level (or indeed the
noise volume). Therefore the original oscillator
signal can be leveled independently of the ring
modulator. Be sure to check out what the ring
modulator does when you select a sine wave
for Oscillator 1 and 2.
Now we can go on and solve the mysteries of
the signal flow as determined by the FILTER
ROUTING operating mode SPLIT: Here Oscillator 1 and the SubOscillator are routed to Filter1, whereas Oscillator 2 and the Noise Generator
are routed to Filter-2. Although the sound
sources are split into two signal paths, you can
still control the volume levels of the different elements as well as OSC VOL in the usual manner.
THE LFOS
When you first started this series of experiments with sounds, we promised that many of
the functions the Virus can be “programmed”
so that they are executed automatically. You
have already learned how to control the volume
and cutoff frequencies of both filters as well as
the pitch and intensity of the frequency modulation of Oscillator 2 via “preprogrammed” envelopes. These options are great, but you have
already encountered a number of functions
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