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Access VIRUS C SERIES Synthesizer PDF Operation & User’s Manual (Updated: Monday 28th of November 2022 12:02:08 AM)

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• ENGLISH VERSION

  ACCESS VIRUS C SERIES

  USER MANUAL OS5

• 2002 Access Music GmbH, Germany.

  VIRUS is a trademark of Access Music GmbH.All other trademarks
  contained herein are theproperty of their respective owners. All
  featuresand specifications subject to change withoutnotice.

  Written by Christoph Kemper, Uwe G. Hnig,Wiland Samolak and Marc
  Schlaile.

  Translation by Thomas Green and HowardScarr. Graphic Design and
  DTP by Babylonwaves Media.

  http://[email protected]

• 2

  1

  Content

  IMPORTANT SAFETY REMARKS

  PROLOGUE

  INTRODUCTION

  The Virus
  ……………………………………………………. 14The
  Amplifier Envelope …………………………………. 17The
  First Filter………………………………………………
  18Filter Modulation
  ………………………………………….. 19The Saturation
  Stage ……………………………………. 21The Second
  Filter …………………………………………. 21Filter
  Routing ……………………………………………….
  24The First Oscillator
  ……………………………………….. 25The Second
  Oscillator …………………………………… 27The Third
  Oscillator………………………………………. 29The
  Mixer Section …………………………………………
  29The LFOs
  ……………………………………………………. 30The
  MOD Section ………………………………………….
  33Soft Knob
  1/2………………………………………………. 33Volume
  and Panorama Position ………………………. 34Velocity
  ……………………………………………………….
  34Unison
  Mode……………………………………………….. 35The
  Effects…………………………………………………..
  36The Arpeggiator
  …………………………………………… 38SoundDiver
  Virus …………………………………………. 38More to
  Come ……………………………………………… 39

  CONCEPT AND OPERATION

  Operating Modes
  …………………………………………. 42Master Clock
  and Midi-Clock …………………………. 44

  Handling………………………………………………………
  44All about the memory
  …………………………………….47The Modulation Matrix
  and Soft Knobs………………48Random Patch
  Generator………………………………..50Categories
  …………………………………………………… 52The
  Effects
  Section………………………………………..52Audio
  Inputs …………………………………………………
  53Internal Audio Routing
  ……………………………………54Additional functions
  ……………………………………….55

  SYNTHESIS PARAMETERS

  OSCILLATORS
  ………………………………………………58

  Oscillator-1/2/3
  (Panel)…………………………………..58Oscillator
  (Edit-Menu) …………………………………….59

  FILTER
  ………………………………………………………..
  63

  Filters (Panel)
  ……………………………………………….63Filter
  Envelope………………………………………………64Filter-Edit-Menu
  ……………………………………………65

  ENVELOPES
  ………………………………………………… 69MIXER
  …………………………………………………………
  70LFO AND MODMATRIX …………………………………..71

  LFO
  (Panel)…………………………………………………..
  71LFO (Edit
  Menu)…………………………………………….73

  ARPEGGIATOR
  EDIT……………………………………….80THE INTERNAL
  EFFECTS ………………………………..82

  Distortion (Panel)
  …………………………………………..82Chorus (Panel)
  ………………………………………………83Chorus
  (Edit Menu) ………………………………………..83Phaser
  (Panel)
  ………………………………………………84Phaser
  (Edit Menu) ………………………………………..84Delay
  /
  Reverb………………………………………………85Delay
  / Reverb (Panel) ……………………………………86Delay
  / Reverb (Menu)
  ……………………………………87Vocoder……………………………………………………….
  92Analog Boost
  ………………………………………………..92Equalizer
  ……………………………………………………..
  92

• ACCESS VIRUS OS5

  3

  MAIN EDIT MENU

  Common……………………………………………………..
  96Unison
  Mode………………………………………………..
  99Punch Intensity
  ………………………………………….. 100Envelope
  Sustain Time………………………………… 100Analog
  Inputs……………………………………………..
  100Follower (Envelope-Follower) ………………………..
  102Ringmodulator
  …………………………………………… 102Second
  Output/Surround……………………………… 103Velocity
  ……………………………………………………..
  104Sound Category ………………………………………….
  106Soft Knob-1/2
  ……………………………………………. 106

  MULTI MODE & SYSTEM SETUP

  MULTI MODE PARAMETERS ………………………… 110SYSTEM
  ……………………………………………………
  114

  Keyboard
  …………………………………………………..
  114Input
  …………………………………………………………
  116MIDI………………………………………………………….
  117System
  ……………………………………………………..
  121

  THE KEYBOARD VERSIONS OF THE VIRUS

  The VIRUS kc and the indigo ……………………….. 126The
  Keyboard-Modes ………………………………….. 128

  THE VOCODER OF THE VIRUS

  Vocoder
  …………………………………………………….
  132The parameters of the VIRUS Vocoder ……………. 134Notes
  about the vocoder: …………………………….. 137

  THE VIRUS AND SEQUENCERS

  Problems Related to Parameter Control
  …………..144Arrangement Dump — The Sound in the
  Song……145

  TIPS AND TRICKS

  All abouts
  Inputs………………………………………….148About the
  Delay/Reverb ………………………………..149The Virus as
  an Effect Device ………………………..150Envelope Follower
  ……………………………………….150Oscillators
  ………………………………………………….
  151Filters………………………………………………………..
  153Saturation for Added Grit and Dirt
  …………………..153LFOs
  …………………………………………………………
  154Volume Control
  ……………………………………………155Assign and
  the Soft Knobs …………………………….156Arpeggiator
  ………………………………………………..156How to
  modulate the Vocoder parameters ……….156MIDI
  ………………………………………………………….
  157How to install Updates
  ………………………………….158

  APPENDIX

  System Exclusive Data
  …………………………………162Parameter Descriptions
  ………………………………..166Multi Dump Table
  ………………………………………..178Classes
  ……………………………………………………..
  180Mod Matrix Sources
  ……………………………………182Mod Matrix
  Destinations ……………………………….183Soft Knob
  Destinations ………………………………..184MIDI
  Implementation Chart ……………………………185FCC
  Information (U.S.A) ………………………………..186FCC
  Information (CANADA) ……………………………187Other
  Standards (Rest of World)……………………..187Declaration
  of Conformity ……………………………..188Garantie
  Bestimmung …………………………………..189Warranty
  ……………………………………………………
  190

• 4

  1

  INDEX

  INDEX
  ……………………………………………………….
  192

• Important Safety Remarks

• 6

  2

  Important Safety Remarks

  Please read all notes carefully before you powerthe device up. A
  few fundamental rules on han-dling electrical devices follow.

  SET-UP

  Operate and store the device in enclosedrooms only.

  Never expose the device to a damp envi-ronment.

  Never operate or store the device in ex-tremely dusty or dirty
  environments.

  Assure that air can circulate freely on allsides of the device,
  especially when youmount it to a rack.

  Dont set the device in the immediate vicini-ty of heat sources
  such as radiators.

  Dont expose the device to direct sunlight.

  Dont expose the device to strong vibrationsand mechanical
  shocks.

  CONNECTIONS

  Be sure to use exclusively the includedmains power supply
  adapter.

  Plug the device only into mains sockets thatare properly
  grounded in compliance withstatutory regulations.

  Never modify the included power cord. If itsplug does not fit
  the sockets you have availa-ble, take it to a qualified
  electrician.

  Always pull the power plug out of the mainssocket when you wont
  be using the devicefor prolonged periods.

  Never touch the mains plug with wet hands.

  Always pull the actual plug, never the cord,when youre
  unplugging the device.

  OPERATION

  Dont set beverages or any other receptaclecontaining liquids on
  the device.

  Make sure the device is placed on a solidbase. Set it on a
  stable tabletop or mount it toa rack.

  Make sure that no foreign objects fall into orsomehow end up
  inside the devices hous-ing. In the event that this should occur,
  switchthe device off and pull the power plug. Thenget in touch with
  an authorized dealer.

  Used on its own and in conjunction withamps, loudspeakers or
  headphones, this de-vice is able to generate levels that can lead
  toirreversible hearing damage. For this reason,always operate it at
  a reasonable volume lev-el.

  MEMORY BATTERY CHANGE

  The VIRUS stores its sound programs in a bat-tery-buffered RAM.
  This battery (general typedesignation: CR2032) should be replaced
  everythree to four years. The housing has to beopened to change the
  battery, so take the de-vice to a qualified service technician. Do
  yourpart in protecting our environment and take it toa shop that
  disposes of batteries properly.

  Before you have the battery changed, save theentire memory
  content of the RAM by loading itto a sequencer via «Total Dump». Be
  advisedthat RAM content is lost when the battery isswapped (see
  «Midi Dump TX» on page 117).).

  CARE

  Do not open the device, it is not equippedwith any
  user-serviceable parts. Repair andmaintenance may only be carried
  out by qual-ified specialists.

• ACCESS VIRUS OS5

  7

  Use only a dry, soft cloth or brush to cleanthe device.

  Do not use alcohol, solvents or similarchemicals. These can
  damage the surface ofthe housing.

  FITNESS FOR PURPOSE

  This device is designed exclusively to generatelow-frequency
  audio signals for sound engi-neering-related purposes. Any other
  use is notpermitted and automatically invalidates thewarranty
  extended by Access Music ElectronicsGmbH.

• 8

  2

  Important Safety Remarks

• Prologue

• 10

  CHAPTER 3

  Prologue

  Dear VIRUS Owner,

  Congratulations on your choice, the new VI-RUS. You have
  purchased a cutting-edge syn-thesizer that comes fully loaded with
  severalrevolutionary features. Here are just a few of
  thehighlights:

  The VIRUS delivers the sound characteristicsand tone of
  traditional analog synthesizers in apreviously unparalleled level
  of quality and han-dling ease. Were not kidding, the VIRUS
  actualdelivers the authentic response of an analogsynth via a
  digital signal processor chip, al-though the sound shaping and
  voicing optionsout-perform those of it historical predecessorsby a
  considerable margin.

  The VIRUS comes with up to 1024 slots forstoring SINGLE sounds.
  These are organized ineight banks. The first two banks (A and B)
  arelocated in the RAM, so you can overwrite themwith new sounds.
  The other six banks arehard-wired, i.e. theyre programmed into
  theFLASH ROM. To make use of the banks E-Hyou need to install the
  second1024.mid file first(The 1024 sounds update on page 158).

  The VIRUS offers a maximum of 32 voices. InMulti Mode, these are
  allocated dynamically tosixteen simultaneously available
  sounds.

  You have no less than three audio oscillatorsplus one
  suboscillator, a noise generator, a ringmodulator, two Multi Mode
  filters, two enve-lopes, a stereo VCA, three LFOs and a satura-tion
  stage (SATURATOR) for cascade filtering,tube and distortion
  effects.

  The VIRUS offers a veritable arsenal of effects.You have seven
  powerful sound-sculpting func-tions, including chorus, phaser and
  distortion,at your disposal, with each effect available sep-arately
  for every sound. Thus, in 16-way MULTImode, the VIRUS offers over
  98 effects, noless!. Among them you also get a global reverb/

  delay unit that lets you create high-quality re-verb effects and
  rhythmic delay taps. Delaytime can be synced up to MIDI clock.

  With the benefit of two external audio inputs,the VIRUS may also
  serve as an FX device andsignal processor that you can use
  creatively tocome up with all kinds of effects. External sig-nals
  can be processed with filter, gate and lo-fieffects, routed to the
  VIRUS effects section andserve as a modulation source for frequency
  andring modulation.

  Beyond that, you can use internal or externalsignals as sources
  for the VIRUS on-boardvocoder serve. The vocoder works with up to32
  filter bands and offers diverse manipulationand modulation
  options.

  The three main oscillators produce 66 wave-shapes, three of
  which are dynamically mixableso that spectral effects are possible
  within theconfines of a single oscillator. In
  conventionalsynthesizers, this type of effect requires
  severaloscillators. Synchronization, frequency modula-tion and ring
  modulation between the audio os-cillators delivers additional
  complex spectraleffects that you can use for all kinds of
  soundshaping purposes.

  The filters can be switched in series or in paral-lel within the
  voices via several options. Whenyou switch the filters in series,
  the saturationstage is embedded between the filters. Conse-quently,
  an overdriven filter resonance can bere-filtered within the same
  voice! A maximum ofsix filter poles (36 dB slope!) enables
  radicaltonal manipulations.

  The LFOs feature 68 continuous variable wave-shapes each,
  including a triangle with variablesymmetry and infinitely variable
  aperiodic oscil-lations for random variation of the
  controlledparameters. The LFOs are capable of poly-phonic as well
  as monophonic oscillation. Inother words, if several voices are
  active, the

• ACCESS VIRUS OS5

  11

  LFOs can run independently or in sync. Anumber of keyboard
  trigger options enable youstart LFO waveshapes with variable
  phaselengths at the beginning of a note and/or to cy-cle once only,
  like an envelope.

  Next to the numerous hard-wired or fixedmodulation
  configurations, you can assignthree modulation sources to up to
  nine differentmodulation destinations via the Modulation Ma-trix.
  For your modulation sources, you haveLFOs, velocity, the pitch
  bender, aftertouch, themodulation wheel, numerous MIDI
  controllersand other sources to chose from. For yourmodulation
  destinations, you can select anysound parameter of the VIRUS that
  is condu-cive to being remote controlled.

  Up to 16 arpeggiators are available in MULTImode. These give you
  countless options forcreating arpeggios, which can also be syncedup
  to MIDI clock.

  Sounds and effects are patched out via six au-dio outputs which
  of course can also be used toroute three stereo signals out.

  In additional to its killer sounds and tone, theVIRUS was
  designed to deliver ultimate han-dling and control comfort. It is
  equipped withdedicated knobs and buttons for the crucialsynthesizer
  functions, further parameters areaccessible via data entry
  procedures. We distin-guished between these two levels of
  expertiseto enable you to create complex sounds whilekeeping the
  user interface as clear and unclut-tered as possible.

  In all modesty, we are especially proud of a fea-ture we
  developed called Adaptive ParameterSmoothing. For the first time in
  the history ofsynthesizers equipped with memories, you
  canmanipulate a knob or control feature without anaudible step or
  increment. In other words, thesound does not change abruptly but
  SEAM-LESSLY. No more zipper noises! The VIRUS re-

  sponds just as smoothly as analog synthesizersdid prior to the
  introduction of digital soundstorage

  And users of contemporary software sequenc-ers will appreciate
  the fact that the VIRUSsends all sound shaping commands
  immedi-ately in the form of MIDI Controller or Poly Pres-sure data
  (and of course accepts all of thecorresponding Controller and SysEx
  messag-es). This feature lets you dynamically control theVIRUS and
  all its functions via computer.

  Although far from complete, the features listedabove give you
  some indication that you nowown an exceptionally versatile,
  high-quality mu-sical instrument that will give you plenty of
  joyfor years to come. We certainly hope you canfully exploit the
  enormous potential of this fineinstrument.

  Have fun and enjoy!Your VIRUS Development Team

  By the way: a rack mounting kit is optionallyavailable for the
  Virus C. Feel free to get intouch with your local authorized dealer
  for moreinfo.

  Many thanks to:Ben Crosland, Maik Fliege, Thomas Green,
  AxelHartmann, Uwe G. Hnig, Jrg Httner, TimoKaluza, Oliver Kser,
  Andrea Mason, ThorstenMatuschowski, Jrg Meiner, Paul Nagel,
  KaiNiggemann, Rob Papen, Matt Picone, WielandSamolak, Daniela
  Sauerbier, Howard Scarr,Hans-Jrg Scheffler, Shehryar Lasi, Jenny
  Si-mon, Matt Skags, Joeri Vankeirsbilck, JayVaughan, Jens Wegerhoff
  and Daniel Wewer.

• 12

  CHAPTER 3

  Prologue

• Introduction

• 14

  CHAPTER 4

  Introduction

  THE VIRUS

  This section provides deliberate, step-by-stepguidelines on
  operating and handling the VIRUSfor those of you who are new to the
  world ofsynthesizers and MIDI. The following covers ba-sics such as
  how to connect the VIRUS to anAC power supply, your MIDI system and
  youraudio system. Then we will guide you through aseries of
  experiments designed to demonstratethe different functional groups,
  their control fea-tures and the tasks they execute.

  After you have finished reading this section, youwill be able to
  handle virtually all of the soundgenerating and sound shaping
  functions of theVIRUS. All of these are described in context,along
  with their control features. Even the ma-jority of less significant
  functions, accessible viamenus, are discussed here. You will find a
  de-tailed, comprehensive description of all func-tions of your new
  synthesizer in the sectionfollowing this introduction.

  Please keep in mind that within confines of thisintroduction, we
  are unable to impart all of theknowledge and skills in acoustics,
  sound syn-thesis and MIDI control you might desire orneed to
  acquire. If you are keen to learn moreabout these subjects, you
  should consider be-coming a regular reader of one or several of
  theleading trade publications in your country. Yourlocal musical
  instruments dealer or more expe-rienced musicians will be able to
  recommendthe best magazines to you. And of course thereis a wide
  range of books available on thesesubjects.

  If you decide to read this section, we recom-mend you read it in
  its entirety from the start -rather than begin with a subsection
  that is ofparticular interest to you. A fitting metaphor forthe
  basics discussed in this section might be ahouse where each bit of
  information in a sub-

  section is a brick that builds on a precedingbrick and
  interlocks with those next to it. Youwant your knowledge base to be
  a sound struc-ture so you wont run into problems when youfind one
  of the bricks is missing.

  CABLE CONNECTIONS

  Before you connect the VIRUS to an AC outletand the rest of your
  equipment, ensure that allof the devices are switched OFF. If your
  VIRUSdoes not have a build-in keyboard, then con-nect the MIDI OUT
  of the desired MIDI send de-vice (keyboard, computer, hardware
  sequencer,etc.) with the MIDI IN of the VIRUS.

  Connect the audio outputs of the VIRUS withthe signal inputs of
  your audio system. In orderto receive a signal, as a minimum you
  mustconnect the output OUT 1 R/MONO. However,we recommend you also
  connect the outputOUT 1 L so you are able to enjoy the stereosounds
  of the VIRUS.

  Once you have established the desired cableconnections, make
  sure the main volume con-trols of all the connected devices (VIRUS:
  MAS-TER VOLUME, located at the upper left hand ofthe control panel)
  are dialed to the lowest pos-sible setting. Switch the devices on
  in the fol-lowing sequence: the MIDI send device(computer, master
  keyboard, etc.) first, then thesound generators (VIRUS and the
  other signalsources), followed by the mixing console and fi-nally
  the amplifier.

  Now while you are sending notes on MIDIChannel 1 of the VIRUS,
  turn the master vol-umes of the connected devices up in the
  sameorder that you switched the devices on. Be sureto keep on eye
  on the signal level indicators ofyour mixing console.

• ACCESS VIRUS OS5

  15

  The Virus

  MASTER VOLUME

  Controls the overall volume of the VIRUS. Thiscontrol determines
  the volume of the signal pairpiped through Output 1 before it is
  convertedinto an analog signal. This means that undernormal
  circumstances, you should turn MasterVolume all they way up because
  you of coursewant the VIRUS to deliver the most dynamicsignal
  possible.

  LISTENING TO THE FACTORY SOUNDS

  The program memory of the VIRUS was loadedwith sound programs
  (SINGLE PROGRAMs)and sound combinations (MULTI PROGRAMs)before it
  left the factory. To hear the SINGLEPROGRAMs (and gain an initial
  impression ofthe possibilities your new instrument has to of-fer in
  terms of sounds), first make sure yourMIDI source is sending on
  MIDI Channel 1.

  Press the SINGLE button. A number, a letter,number and name
  appear in the display. Theseindicate the the MIDI Channel, the
  current Pro-gram Bank (A to D or A to H) as well as thenumber and
  name of the current sound pro-gram.

  Now if you play notes you should be able tohear this sound and
  a

  note (the round dot atthe end of the note staff is solid black)
  shouldappear in the display every time you press a keyand release a
  key. If you do not hear a soundbut you see a half note (blank note
  head) checkto see if you are sending on the wrong MIDIChannel.

  Press the VALUE button to call up the 128 sin-gle programs of
  Bank A in sequence. (The VAL-UE pot is inactive in this operating
  mode.) Inorder to hear the sound programs in banks B, C

  and so on, simply use the PARAMETER/BANKbuttons to step from one
  program bank to an-other.

  Youll find that some sound programs are la-beled with the
  abbreviations INP or VOC.These use the external audio input as a
  signalsource for the filter section (INP) or vocoder(VOC). This
  means that you wont hear anythinguntil you route an audio signal
  into the externalaudio inputs.

  Tip: You can trigger a note on the Virus bypressing both the
  EDIT and SYNC buttons inthe OSCILLATORS section at the same time
  this is the AUDITION function, which is espe-cially useful for
  auditioning sounds when thereis no keyboard connected to the
  Virus.

  Call up each of the 128 programs in Bank A inturn. You can do
  this either with the VALUEkeys (which simply increment/decrement
  theprogram number), or by holding down the MUL-TI key and scrolling
  through programs with theVALUE knob. To try out all the other
  sounds inbanks B to H, simply switch banks with the PA-RAMETER/BANK
  buttons.

  SOFT KNOB 1SOFT KNOB 1SINGLESINGLEMULTIMULTI

  UNDOUNDO

  — +

  STORESTORE

  MULTISINGLEMULTISINGLE

• 16

  CHAPTER 4

  Introduction

  SOUND CATEGORIES

  To help you find the type of SINGLE sound youare looking for
  more quickly, the Virus operatingsystem lets you define so-called
  categoriesand save this information together with each ofyour
  SINGLE sounds.

  Available categories are:

  Off, Lead, Bass, Pad, Decay, Pluck, Acid, Clas-sic, Arpeggiator,
  Effects, Drums, Percussion, In-put , Vocoder, Favour i te1 , Favour
  i te2 ,Favourite3

  Each SINGLE sound can belong to two cate-gories at the same
  time. Of course the catego-ries of all the presets in Banks C to H
  are fixed,but for sounds in the RAM Banks (A and B) theycan be
  defined and saved together with theprogram.

  To search for sounds in a specific category (inSINGLE or
  MULTI-SINGLE mode):

  Press and hold the SINGLE button. This causesthe currently
  selected category to appear in thedisplay, and it can be changed by
  stepping upor down with the Parameter buttons. Havingfound the
  category you want, do not release theSINGLE button and scroll
  through the soundsusing the Value buttons. Release the SINGLEbutton
  when you have found what you are loo-king for. SINGLE sounds which
  do not belongto the currently selected category are simplyskipped
  over.

  LISTENING TO THE MULTI PRO-GRAMS

  The VIRUS not only has the capability of playingSINGLE PROGAMs,
  but also combinationsconsisting of more than one sound
  simultane-ously (MIDI Multi Mode). To call up the MULTIPROGRAMs,
  press the MULTI button and se-

  lect these combination programs via the VALUEbutton. The VIRUS
  features only 128 MULTIPROGRAMs, so you dont have to switch backand
  forth between banks they way you just didwhile activating single
  programs.

  The majority of available MULTI PROGRAMscontain sound
  combinations that are controlledvia a single MIDI channel. In these
  MULTI PRO-GRAMs, the sounds involved are allocatedside-by-side
  (split) or on top of one another(layered) on the keyboard. In other
  MULTI PRO-GRAMs, the sounds are divided up over severalMIDI
  channels to make it easier to work with asequencer. If you activate
  a MULTI PROGRAMand hear a single sound only, then you can con-trol
  this MULTI PROGRAM via several channels.

  YOUR FIRST SOUND PROGRAM

  If you have never created or changed a soundon a synthesizer, we
  now have the pleasure ofintroducing you to this fascinating
  process.

  Select the single program C127 — START -.Press any key on the
  connected keyboard. Youshould hear a sound that, for lack of better
  de-scription, is a bit harsh or biting, but above allcompletely
  static. It should start immediatelyafter you press a key and
  sustain indefinitely foras long as you hold the key down. As soon
  asyou release the key, the sound should endabruptly. This sound is
  not designed to be es-pecially pleasant; it is intended to be as
  neutralas possible to give you a basis from which youcan begin
  creating or shaping your own sound.

• ACCESS VIRUS OS5

  17

  The Amplifier Envelope

  THE AMPLIFIER ENVELOPE

  Long-term exposure to this sound will definitelygrate on your
  nerves, so lets get started withchanging it into a signal you might
  enjoy hear-ing, beginning with the volume characteristics.Locate
  the section labeled AMPLIFIER at thebottom right of the control
  feature panel of theVIRUS. Here you can see four pots labeled
  AT-TACK, DECAY, SUSTAIN and RELEASE, re-spectively.

  These controls will help you to dial in volumecharacteristics
  called an amplifier envelope andput an end to the nerve-racking
  drone that mayremind you of one of those cheesy organs thatyou hear
  in 60s B-movie sound tracks.

  Rotate the ATTACK pot while you repeatedly

  engage a key to hear the note. The further youturn the pot up,
  the longer it takes for the soundto achieve maximum volume after
  the start ofthe note. So you can say ATTACK controls theinitial
  volume swell of the sound.

  Presumably the ATTACK pot was set to a ran-dom position before
  you made any adjust-ments. Nevertheless the volume
  automaticallyincreased to the maximum level before youstarted
  rotating the pot. The reason for this isthat an ATTACK value of 0
  is saved in the soundprogram — START — and this value remains
  validuntil you determine a new value by adjustingthe position of
  the pot, even if you turn it everso slightly.

  Take a look at the display of the VIRUS to gainan impression of
  the difference between thesetwo values. It shows two numeric values
  whenyou dial a pot: at the left you can see the valuestored in the
  sound program and at the right,the numeric equivalent to the value
  determinedby the current position of the pot.

  Always keep in mind that for a programma-ble synthesizer the
  position of the control fea-ture or pot does not necessarily
  indicate theactual value of the given function. The reasonfor this
  is that when you first activate a soundprogram, it will reflect the
  programmed value.You have to adjust the control feature beforethe
  programmed value is superseded by the val-ue you determine
  manually.

  Now fiddle with the DECAY pot while you re-peatedly press a key
  to activate a note. Holdthe key down for good while. You will
  noticethat the volume, once it reaches maximum levelat the end of
  the ATTACK phase, drops until itreaches a minimum level. The DECAY
  pot de-termines the speed, or in synthesizer jargon, therate at
  which the volume decreases.

  However, the DECAY level does not alwaysdrop to the minimum
  level; you can determine arandom value between the maximum and
  mini-mum levels at which the volume remains con-stant. This level
  in turn is controlled via theSUSTAIN pot.

  Whenever the SUSTAIN level is set to maxi-mum, the volume cannot
  drop during the DE-CAY phase; in other words, in this situation
  theDECAY pot is ineffective.

  The individual functions of a synthesizer aredesigned to
  interact; many functions are depen-dent on other functions. In a
  number of casesthis means that some functions are subordinate

  ATTACKATTACK DECAYDECAY SUSTAINSUSTAIN RELEASERELEASE

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  AMPLIFIERAMPLIFIER

• 18

  CHAPTER 4

  Introduction

  to others, i.e. the effectiveness of a control fea-ture is
  altered, modified or even negated com-pletely by other related
  functions.

  The final pot, RELEASE, determines the speedor rate at which the
  volume decreases whenyou release the key: At low values the
  soundends relatively abruptly, at high values, thesound fades out
  more gradually and softly. Thelength of the RELEASE phase also
  depends onwhich level the amplifier curve is at when yourelease the
  key: The lower the level, the shorterthe RELEASE phase. If you
  dialed in a brief DE-CAY or SUSTAIN-TIME phase and it endedwhile
  you held the key down then of coursethere will not be an audible
  RELEASE phase.

  The amplifier envelope can be described as avariable curve
  which, depending on the typeand duration of attack, hold and
  release data,automatically influences an imaginary volumepot (turns
  it up or down). At the beginning of thenote, ATTACK controls the
  rise or rate of in-crease to the maximum level. Once the maxi-mum
  level is achieved, DECAY determines thefall or rate of decrease to
  the SUSTAIN value,which is infinitely variable between the mini-mum
  and maximum levels. The amplifier enve-lope may remain at this
  value until the end ofthe note, fall towards the minimum level as
  de-termined by the variable TIME value, or evenrise again towards
  the maximum level. After theend of the note, RELEASE controls the
  fall orrate of decrease to the minimum level. Conse-quently, the
  control pots labeled ATTACK, DE-CAY, TIME and RELEASE control a
  speed orrate, where as SUSTAIN actually controls a lev-el.

  THE FIRST FILTER

  Now we will take a look at a component of asynthesizer that is
  generally regarded as themost important functional unit as it
  enablesdrastic sound shaping measures: the filter — orin the case
  of the VIRUS, the two filters.

  But first we will concentrate on just one of thetwo filters.

  Locate the Cutoff pot (not to be confused withCutoff 2!) in the
  section labeled FILTERS, direct-ly above the section labeled
  AMPLIFIER. Rotatethe pot to the left and right and note how
  thesound becomes muddier and clearer in re-sponse to the direction
  in which you turn thepot. (To ensure this effect and the following
  au-ral experiments are most pronounced, adjustthe amplifier
  envelope so that the VIRUS gener-ates a constant level while you
  hold a keydown).

  This is how a low pass filter works: it suppress-es, or in
  technical jargon, attenuates the higherfrequencies in a signal and
  allows the lower fre-quencies through. Think of the Cutoff pot as
  abouncer and the VIRUS as your pub. You cantell it which
  frequencies to let in and which fre-quencies to keep out. The
  frequencies abovethe so-called cutoff or filter frequency are
  sup-pressed, those below it remain unaffected.

  -100%-100%

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  2

  FILTER BALANCEFILTER BALANCECUTOFFCUTOFF RESONANCERESONANCE ENV
  AMOUNTENV AMOUNT

  CUTOFF 2CUTOFF 2 SELECTSELECTMODEMODEFILT 1FILT 1 FILT 2FILT
  2EDITEDIT

  BPBP

  BSBS

  HPHP

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  FILT 2FILT 2FILT 1FILT 1

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• ACCESS VIRUS OS5

  19

  Filter Modulation

  Now locate the FILT 1 MODE switch, which isalso located in the
  FILTERS section. It enablesyou to select a filter operating mode
  from thefour available options:

  — LP

  the low pass filter we have just discussed.

  — HP

  the high pass filter which works in the op-posite manner of the
  low pass filter: It sup-presses the lower frequencies in a signal
  andlets the higher frequencies pass.

  — BP

  the band pass filter which suppressesboth ends of the tonal
  spectrum and allowsonly a narrowly defined bandwidth of theoriginal
  sound to pass.

  — BS

  The band stop filter, band reject filter ornotch filter which
  works in the opposite man-ner of the bandpass filter. It allows all
  of thefrequencies of a signal except for a narrowfrequency band
  around the cutoff to pass.The term notch is fairly descriptive;
  youmight say this filter chops a notch out of thesound
  spectrum.

  Now activate the different operating modes androtate the Cutoff
  pot to get a feel for the wayeach filtering option works.

  Along with the Cutoff pot, the RESONANCE potis the most
  important control feature of a filter.The filter resonance
  increases the volume of thefrequencies located near the cutoff
  frequenciesand suppresses the more remote frequencies.This sound
  shaping feature has a striking effect- especially when used in
  conjunction with thelow pass filter: it produces a nasal or
  honkingtype of tone which increases as you turn the

  resonance up. Experiment by varying the RES-ONANCE setting in
  the different operatingmodes in conjunction with different Cutoff
  set-tings. You will find the effect that the RESO-NANCE pot
  achieves is markedly different forthe band stop filter in
  comparison to the effect ithas on the other filter types: as the
  resonanceincreases, the bandwidth of the notch decreas-es; in other
  words more frequencies on bothsides of the filter frequency are
  allowed to pass.

  FILTER MODULATION

  Of course we dont want to require you to exe-cute every sound
  modification manually bytwiddling pots. All kinds of sound
  modificationsin the VIRUS can be executed automaticallymuch in the
  way of your previous experimentswith the volume controls: The
  amplifier enve-lope can be described as a variable curvewhich,
  depending on the type and duration ofattack, hold and release data,
  automatically in-fluences (turns it up or down) an imaginary
  vol-ume pot.

  Similar procedures are applicable to the filterfrequencies. The
  FILTERS section features itsown envelope, the structure of which is
  identi-cal to the amplifier envelope, located directlyabove the
  amplifier envelope on the control fea-ture panel. Much like the
  amplifier envelope, thefilter envelope automatically rotates the
  Cutoffpot.

  However there is one significant difference be-tween the two
  envelopes. With the amplifier en-velope, you are always dealing
  with an initialvolume level of 0 because of course you wantabsolute
  silence prior to the beginning of anote. After the RELEASE phase,
  it is again

  SELECTSELECTMODEMODEFILT 1FILT 1 FILT 2FILT 2EDITEDIT

  BPBP

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  HPHP

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• 20

  CHAPTER 4

  Introduction

  highly desirable that your box is silent. With thefilter
  envelope, the situation is somewhat differ-ent: It always starts at
  the Cutoff value that youdetermined manually. And it is definitely
  not al-ways desirable that the filter frequency isbrought to the
  maximum level.

  Consequently, you need a tool that limits the ef-fective range
  of the fi lter. This is why weequipped the VIRUS with a control
  labeled ENVAMOUNT (short for Envelope Amount). Whenthe pot is
  turned counter-clockwise to the farleft, the filter has no effect
  on the cutoff fre-quency; the further you turn the pot to the
  right,the greater the effect the filter envelope has onthe filter
  frequency. The maximum level of theenvelope may lie outside the
  audible rangewhen the filter has already been partiallyopened via
  the Cutoff pot or was manipulatedvia other control options. In
  extreme caseswhere the filter is already completely open, thefilter
  frequency cannot be increased regardlessof how high you set the ENV
  AMOUNT.

  Go ahead and spend some experimenting withdifferent ENV AMOUNT,
  Cutoff and RESO-NANCE settings for the diverse filter
  operatingmodes. Also try varying the settings for the am-plifier
  envelope. You will find that with just thesefew parameters you are
  able to come up with avast amount of sound settings. If you
  areamong the many musicians who are associativelisteners, you might
  say many of the settingsproduce sounds reminiscent of
  stringed-instru-ments; some sound picked, p lucked orsnapped,
  others sound bowed.

  For your next experiment set the amplifier enve-lope so that you
  hear a constant level when youpress and hold a note. Now deactivate
  the filterenvelope by setting the ENV AMOUNT to 0.
  SetFilter-1Filter-1 to low pass mode and decreasethe filter
  frequency until you just barely hear amuddy signal when you play
  notes in the mid-range.

  Now play a few higher and lower notes. You willfind that the
  lower notes have a greater over-tone content, whereas the higher
  notes soundmuddier and their volume decreases until thenotes are
  completely inaudible. You might al-ready suspect what this is all
  about: As thenotes are transposed ever lower, more portionsof the
  signal fall below the cutoff frequency,whereas with the notes that
  are transposed ev-er higher, more portions of the signal rise
  abovethe cutoff frequency and subsequently are sup-pressed until
  the root note and the last audibleportion of the signal is
  silenced.

  To avoid this effect — or if desirable, to amplify it- you have
  the option of influencing the cutofffrequency via the pitch of the
  note, i.e. the notenumber. The degree of influence is determinedby
  the KEY FOLLOW. You find this parameterwithin the Filter Edit
  menu.

  Please note that KEY FOLLOW is a so-calledbipolar parameter: Its
  control range is not limit-ed to the positive end of the spectrum
  (0 to amaximum of 127). Bipolar controls effect nega-tive values as
  well, in this case from the nega-tive maximum of -64 through 0 an
  on to thepositive maximum of +63. Consequently, if thispot is set
  to the center position (12 oclock or 0)the pitch of the notes
  corresponding to the keyson your keyboard has no effect on the
  cutofffrequency. If on the other hand you turn the KEYFOLLOW pot
  clockwise towards the positivecontrol range, you will find that the
  filter opensup increasingly as the pitch increases with high-er
  notes. At lower notes, the filter closes downagain. If you turn the
  pot counter-clockwise to-

  -100%-100%

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  CUTOFFCUTOFF RESONANCERESONANCE ENV AMOUNTENV AMOUNT

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• ACCESS VIRUS OS5

  21

  The Saturation Stage

  wards the negative control range, the KEYFOLLOW effect is
  reversed. With the VIRUS,you will encounter this feature —
  intensity controlvia a bipolar parameter — again in conjunctionwith
  other modulation sources and targets.

  Now experiment as much as you like with differ-ent KEY FOLLOW
  settings and tune the set-tings via the Cutoff pot. And remember to
  bringall of the other parameters you have encoun-tered thus far
  into play.

  THE SATURATION STAGE

  In the signal chain of the VIRUS, Filter-1 is fol-lowed by a
  saturation stage. It enables you toadd overtones to the filtered
  signal via distor-tion. Locate and press the button labeled EDITin
  the FILTERS section.

  01111111111111111112

  1 SATURATION Curve Off 61111111111111111154

  The display will read SATURATION CURVEOFF, which means exactly
  what it says. Withthe VALUE buttons or the VALUE pot, you cannow
  select from a number of saturation/distor-tion curves. Next to the
  distortion curves, theSATURATION stage offers further DSP
  effectssuch as the shaper, rectifier and filter. These areexplained
  in detail in the section on the SATU-RATION stage.

  At this point we would like to mention the OSCVOL pot in the
  MIXER section. The portion ofthe control range from the far left to
  the center

  position (12 oclock) determines the volume ofthe filter sections
  input signal. The portion ofthe control range located to the right
  of thecenter position (12 oclock) does not achieveany increase in
  volume; it simply intensifies thedegree of saturation or
  distortion. This effect isonly achieved when you have activated a
  satu-ration curve. The intensity of the remainingavailable DSP
  effects is also controlled via theOSC VOL knob.

  Feel free to experiment with the diverse satura-tion curves and
  be sure to vary the OSC VOLsettings. Note how the different Cutoff
  andRESONANCE settings influence the saturationcurve.

  THE SECOND FILTER

  You probably noticed that by a adding a bit ofsaturation to the
  signal you can come up with apretty heavy, aggressive sound —
  especially witha low filter frequency level and high
  resonance.Youre probably thinking these types of soundscould do
  with some more filtering. We had thesame idea, which is one of the
  reasons why weequipped the VIRUS with another filter pervoice.

  6-

  OSC VOLOSC VOL

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• 22

  CHAPTER 4

  Introduction

  The technical design of this second filter isidentical to the
  first, so we wont discuss it inas much detail as we did the first
  filter. Howev-er, there are few differences in how you handlethe
  second filter:

  Only two control features of the VIRUS are al-located
  exclusively to Filter-2: Cutoff-2 and FILT2 MODE.

  The RESONANCE, ENV AMOUNT and KEYFOLLOW pots can be allocated to
  either of thetwo filters or both simultaneously. Use the
  twoSELECT-buttons located at the far right of theFILTERS section to
  select the desired operatingmode. For instance, if you press the
  FILT 2 SE-LECT button, then the values you set via theRESONANCE,
  ENV AMOUNT and KEY FOL-LOW pots apply exclusively to Filter-2.
  Thecorresponding parameters of Filter-1 remain un-affected. On the
  other hand, if you press bothSELECT buttons at the same time, the
  valuesthat you dial in apply by the same measure toFilters 1 and
  2.

  In the sound program we are using for our ex-periments, the LEDs
  of both buttons are illumi-nated, so that all adjustments to the
  givenparameters affect both filters. However, youhave yet to
  actually hear the effect of Filter-2 onthe signal because it is
  mixed out of the audiblesignal path of the VIRUS.

  Before we get started with our next experiment,deactivate
  SATURATION, set the ENV AMOUNTof the filter envelope to zero and
  set Cutoff 2 tothe center position (12 oclock) so that
  Filter-2always has the same cutoff frequency as Filter-

  1 (well explain Cutoff 2 a bit later). Set Cutoff toa medium or
  middle value and turn the RESO-NANCE pot counter-clockwise to the
  far left toachieve a relatively muddy sound. Now locatethe FILTER
  BALANCE pot at the upper righthand of the control panel and rotate
  it from theleft to the right. You will note the sound be-comes
  muddier as you turn the pot towards thecenter position (12 oclock)
  and that the soundis somewhat brighter at the far right of the
  con-trol range then at the far left.

  The reason for this effect is that when you turnthe FILTER
  BALANCE pot to the far left, only Fil-ter-1 is audible. When you
  rotate the pot to theright, Filter-2 is blended in so that it
  follows Fil-ter-1 in the signal chain. When you turn the FIL-TER
  BALANCE pot clockwise, Fi l ter-1 isblended out of the signal chain
  until at the farright position only Filter-2 is active and
  audible.

  Each filter in the VIRUS normally features 2poles. However in
  the FILTER ROUTING oper-ating mode SER 6, Filter-1 operates with
  4poles, so the signal patched through Filter-1(FILTER BALANCE to
  the far left) is trimmedmore drastically than when it is routed
  throughFilter-2 (FILTER BALANCE to the far right).When you set the
  FILTER BALANCE pot to thecenter position (12 oclock) — as we
  mentionedbefore — the two filters are routed in series,which means
  they respond as if they were a sin-gle filter with 6 poles and
  consequently a greatdeal of slope. This is why the input signal
  istrimmed substantially when you set the pot tothis position.

  Experiment with the diverse FILTER BALANCEpositions to get a
  feel for the different degreesof slope. Rotate the Cutoff pot or
  activate thefilter envelope (for both filters!) to hear the
  filtersin action.

  The Cutoff 2 pot is a special feature: It controlsthe cutoff
  frequency of the second filter, but issubordinate to the Cutoff pot
  located above it.

  6-

  0

  6

  FILTER BALANCEFILTER BALANCECUTOFFCUTOFF RESONANCERESONANCE ENV
  AMOUNTENV AMOUNT

  CUTOFF 2CUTOFF 2 SELECTSELECTMODEMODEFILT 1FILT 1 FILT 2FILT
  2EDITEDIT

  BPBP

  BSBS

  HPHP

  LPLP

  FILT 2FILT 2FILT 1FILT 1

• ACCESS VIRUS OS5

  23

  The Second Filter

  In other words, at the center position (12oclock) the manually
  selected frequency of Fil-ter-2 is identical to that of Filter-1.
  When you ro-tate the pot to the left the cutoff frequency levelof
  Filter-2 is increased relatively to Filter-1,when you turn to pot
  to the right the cutoff fre-quency level is decreased relatively.
  Now whenyou adjust the Cutoff pot, you adjust the cutofffrequency
  of both filters by the same measure!This feature lets you determine
  a difference invalues in the filter frequencies (called an
  offset)via the Cutoff2 pot which remains constantwhenever you
  adjust the Cutoff pot.

  Yet another experiment in which you can comeup new filtering
  characteristics that are typicalof the VIRUS:

  Set the FILTER BALANCE pot to the center po-sition (12 oclock)
  and Cutoff 2 to the maximumlevel. The FILTER ROUTING operating
  modemust remain SER 6. Set Cutoff and RESO-NANCE to a middle value
  and select a clearlyaudible SATURATION curve.

  Now you can filter this complex signal pro-duced by a
  combination of the saturation stageand the Filter-1 yet again.
  Rotate the Cutoff 2pot slowly towards the center position
  (12oclock). You can hear how Filter-2 graduallymodifies the
  distorted signal. You can set aRESONANCE value for Filter-2 if you
  press theFILT 2 SELECT button and rotate the RESO-NANCE pot to the
  desired position. Set the Cut-off 2 pot to a position to the right
  of the centerposition. This configuration can be describedas a
  complex non-linear filter set up where thecutoff frequency is
  controlled via the Cutoff pot.You can dial in a wide range of
  sound-shapingoption via Cutoff 2. Also try modifying the
  reso-nances of both filters as well as the SATURA-TION curve to
  come up with different filteringcharacteristics.

  Now experiment with the diverse filter modesand listen closely
  to the effect of the parame-ters RESONANCE, ENV AMOUNT and
  KEYFOLLOW in conjunction with the SELECT but-ton. Please also keep
  in mind that the chancesof choking a sound off are substantially
  greaterwhen you are using both filters: For instance, ifthe first
  filter is used as a low pass with a lowcutoff frequency and the
  second as a high passwith a high cutoff frequency, the VIRUS will
  notgenerate an audible signal when you set theFILTER BALANCE pot to
  the center position (12oclock).

• 24

  CHAPTER 4

  Introduction

  FILTER ROUTING

  The final parameter well discuss for the timebeing is FILTER
  ROUTING. This feature offersseveral filter routing options which
  allow you tooperate the filters in series, i.e. patch one afterthe
  other in the signal chain, or in parallel, whichmeans side by side
  in the signal chain:

  — SER-4 The filters are switched in series; withtwo poles each
  (12dB/Okt.), both filters havethe same slope for a total of four
  filter poles(24dB/Okt.).

  — SER-6 The filters are switched in series; Fil-ter-1 has four
  poles (24dB/Okt.), Filter-2 hastwo poles (12dB/Okt.) so the overall
  slope isequivalent to six poles (36dB/Okt.).

  — PAR-4 The filters are switched in parallel andfeature two
  poles each (12dB/Okt.).

  — SPLIT The filters are switched in parallel andfeature two
  poles each (12dB/Okt.). Addition-ally, they receive independent
  input signals(more on this later). Each of the two oscilla-tors
  routes its signal into one of the two filterswhose signals can be
  spread in the panoramavia a parameter called UNISON Pan Spread.

  Regardless of which FILTER ROUTING op-tion you chose, the
  SATURATION stage is al-ways post-Filter-1, i.e. after Filter in the
  signalchain.

• ACCESS VIRUS OS5 25The First Oscillator

  THE FIRST OSCILLATOR

  To this point, we have turned our attention ex-clusively to
  sound-shaping functions and havealways started with the same basic
  material: aso-called sawtooth wave. This waveshape isespecially
  well-suited as a neutral starting pointas it contains all of the
  so-called natural scale ofovertones, which give the filter plenty
  of qualitymaterial to work with.

  The filters, with the exception of a notch filter orband stop
  (BS), trim the far reaches of the tonalspectrum, so for instance a
  signal sounds mud-dier after it has been routed through a low
  passfilter. You can well imagine that this type ofsound
  modification is substantial but insuffi-cient for shaping more
  subtle differences intone. For instance the tone of a trumpet
  differssignificantly from that of a saxophone eventhough no one
  would seriously claim that eitherof the instruments has a muddier
  tone than theother.

• 26 CHAPTER 4Introduction

  What you need is a sound-shaping option forthe portion of a
  signal that a filter allows topass. And of course you also need a
  tool for de-termining the pitch of a signal. In synthesizers,both
  of these tasks are executed by oscillators.They oscillate at a
  variable pitch that can bemodulated and they also generate
  differentwaveshapes which give the filters a wider varie-ty of
  material to work with.

  The VIRUS is has two main oscillators and a so-called
  suboscillator. Lets take a look at Oscilla-tor 1, the one you have
  already heard in actionduring your experiments so far:

  Start with the same basic sound you used atthe very beginning.
  Now modify the amplifierenvelope to make the sound less grating,
  buthold back on any other filter or saturation modi-fications for
  the moment so you can hear thepure, unadulterated oscillator.

  Oscillator 1, the one you have already heard inaction during
  your experiments so far:

  Start with the same basic sound you used atthe very beginning.
  Now modify the amplifierenvelope to make the sound less grating,
  buthold back on any other filter or saturation modi-fications for
  the moment so you can hear thepure, unadulterated oscillator.

  Press the OSC 1 button in the OSCILLATORSsection to enter the
  edit pages for oscillator 1.Directly above this button are the
  SHAPE andWAVE SEL/PW controls which determine thewaveform and
  therefore the basic sound of os-cillator 1. The SHAPE parameter is
  currently setto the exact center (value 64), and if you look atthe
  panel directly above the SHAPE conrol, youwill see a symbol
  representing a sawtoothwave.

  You can definitely see why this waveshapebears the name
  sawtooth. Press and hold akey and slowly turn the pot clockwise.
  Youshould be able to hear how the tone becomesincreasingly more
  hollow-sounding. You mightsay this effect thins the sound out, but
  in anycase, the entire tonal spectrum is affected by anequal
  measure, which is an audio result filtersare unable to achieve.

  The waveshape that is audible when you turnthe SHAPE pot to the
  far right is a so-calledpulse wave. The graphical representation of
  thiswaveshape on the control panel gives you agood idea of its
  appearance. It is unique be-cause the duration of the negative
  pulse isequal to the duration of the positive pulse: It hasa
  so-called pulse width of 50%. The tone of apulse wave is different
  to that of a sawtoothwave because it does not contain all
  overtonesin the natural overtone scale, only the odd-numbered
  tones, i.e. the first (the root note thatdetermines the pitch),
  third, fifth, and so forth.By turning the SHAPE pot from the
  sawtoothcontrol range towards the pulse control range,you are
  actually dialing every other overtone outof the mix, which explains
  why the sound be-comes thinner.

  You can continue modifying the sound by re-ducing the
  symmetrical width of the pulsewave. In the VIRUS, you can execute
  thissound-shaping measure via the WAVE SEL/PW

  4848-

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  DETUNE 2 / 3DETUNE 2 / 3SHAPESHAPE / PW/ PWWAVE SELWAVE SEL
  SEMITONESEMITONE

  FM AMOUNTFM AMOUNTEDITEDIT SYNCSYNC SELECTSELECT

  OSC 3OSC 3OSC 2OSC 2OSC 1OSC 1

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  OSCILLATORSOSCILLATORS

  AUDITIONAUDITION

• ACCESS VIRUS OS5 27The Second Oscillator

  (PW = pulse width) pot, PROVIDED THE SHAPEPOT IS SET TO A
  POSITION IN THE RIGHTHALF OF ITS CONTROL RANGE (LATER THAN12
  OCLOCK). Rotate the WAVE SEL/PW potslowly from the left to the
  right and leave theSHAPE pot at the far right position. You canhear
  how the treble content of the sound in-creases while the sound
  becomes ever thinner.At the far right position, the signal is no
  longeraudible because the pulse width is equivalent to0% and
  consequently the wave no longer oscil-lates.

  Starting at the center position (12 oclock) indi-cated by the
  sawtooth, turn the SHAPE potcounter-clockwise towards the left. You
  canhear how the overtones are increasingly mixedout of the signal
  until you can only hear the rootnote. This sound is produced by a
  so-calledsine wave, one of 64 other waveshapes thatyou have at your
  disposal for sound generationpurposes. These waveshapes can also be
  acti-vated via WAVE SEL/PW (WAVE SEL: Wave Se-lect), PROVIDED THE
  SHAPE POT IS SET TO APOSITION IN THE LEFT HALF OF ITS CON-TROL
  RANGE (EARLIER THAN 12 OCLOCK).Regardless of the current SHAPE
  setting, youcan also select a wave in the EDIT menu underOSCILLATOR
  1 WAVE.

  Go ahead and check out the different wave-shapes. The second of
  the 64 waves is a trian-gle wave, the remainder of the waveshapes
  areeach a unique tonal blend. After you have famil-iarized yourself
  with this raw material, experi-ment with the parameters of the
  FILTERS andAMPLIFIER sections you have dealt with thusfar (dont
  forget about SATURATION and thecorresponding function of the OSC
  VOL pot), toget a feel for how the diverse waveshapes re-spond to
  filtering, saturation and amplifier mod-ifications.

  THE SECOND OSCILLATOR

  As already mentioned above, the Virus has asecond oscillator (as
  well as several other basicsound sources which will be described
  later inthis manual). Press the OSC 2 button in the OS-CILLATORS
  section to enter the edit pages forthe oscillator 2. The controls
  in this section nowapply to oscillator 2 only oscillator 1
  parame-ters cannot be changed now (although the os-cillator can
  still be heard).

  Dial in the basic sound program that you had atthe very
  beginning; change the amplifier enve-lope to suit your taste. In
  the sound program,the OSC BAL (Oscillator Balance) pot in theMIXER
  section is preset to the far left. In orderto hear Oscillator 2 in
  action, rotate the OSCBAL (Oscillator Balance) pot in the MIXER
  sec-tion to the right. Towards the center position (12oclock) you
  will hear how the tone is modifiedand as you rotate the pot further
  to the right,how the intensity of this modification is re-duced.
  This effect is known as the comb filter-ing effect. It occurs when
  two signals with thesame frequency but different phase lengths
  aremixed. Press the same key on your keyboardseveral times with the
  OSC BAL set to the cent-er position (12 oclock). You should notice
  thateach note has a slightly different tone. The os-cillators are
  the source of this effect. The oscil-l a to rs o f the V IRUS osc i
  l l a te f r ee ly,consequently every time you play a note,
  thephase constellation between the two oscillatorsis different. For
  now, leave the OSC BAL POT atthe center position (12 oclock).

  You are already familiar with Oscillator 1sSHAPE and WAVE SEL/PW
  pots. These func-tions are identical for Oscillator 2, so we wontgo
  into detail on them again.

• 28 CHAPTER 4Introduction

  Locate the pot labeled DETUNE and slowly ro-tate it to the right
  from the far left position(which is preset in the sound program).
  You canhear the tone start to waver and as you turn thepot further
  to the right, how this vibrato effectincreases until Oscillator 2
  sounds distinctly outof tune with Oscillator 1. This wavering or
  vibra-to-type effect has a popular traditional in syn-thesizers. It
  is used to achieve chorus effects,create sounds reminiscent of
  stringed instru-ments/ string sections or simply beef up
  thesound.

  The SEMITONE pot enables you to transposeOscillator 2 by
  plus/minus four octaves in semi-tone steps while Oscillator 1
  maintains thepitch. This feature is especially interesting whenused
  in conjunction with two other oscillatorfunctions: synchronization
  and frequency mod-ulation.

  Locate and activate the SYNC button in theOSCILLATORS section
  (the LED must illumi-nate). The synchronization function forces
  Os-cillator 2 to restart its wave cycle at the sametime as
  Oscillator 1 waveshape starts its cycle.The initial effect of this
  measure is that the wa-vering tone that resulted from detuning
  andmixing the oscillator signals disappears.

  The SYNC effect really becomes interestingwhen you transpose
  Oscillator 2 upwards incomparison to Oscillator 1 via the
  SEMITONE

  pot. What happens is that the wave cycle of Os-cillator 2 is
  interrupted as soon as Oscillator 1starts its cycle. The pitch of
  the second oscilla-tor no longer has the expected effect, instead
  itgenerates special tones, in some cases for lackof a better
  description screaming type effects.

  The other effect that benefits from manipulatingthe interval
  between the oscillators is frequencymodulation (FM). It generates
  new tonal spectrain which the signal of the first oscillator
  controlsthe frequency of the second oscillator similar tothe manner
  in which filters can be controlled viaenvelopes. And here too you
  have a pot whichallows you to control the intensity of: FMAMOUNT.
  Basically, this effect is similar to a vi-brato, although here
  youre dealing with an ex-tremely fast vibrato featuring a frequency
  withinthe range of human hearing. This signal is notactually
  audible as a vibrato effect. Instead,youll hear a sound modulation,
  in some cases,a very drastic one at that. Choose the pure
  sinewaveshape for Oscillator 2. In conjunction withthe sine wave,
  the frequency modulation gener-ates very clear, in some cases
  bell-like, spectra.

  In the VIRUS you have the option of combiningthe two functions
  called oscillator synchroniza-tion (SYNC) and frequency modulation
  (FMAMOUNT, to generate new harmonic spectra.Switch SYNC on and
  experiment with the FMAMOUNT. Also try out different SEMITONE
  set-tings and the diverse waveshapes of Oscilla-tor.The VIRUS is
  equipped with a third masteroscillator that lets you create further
  oscillationsand spectra. You can access the parameters ofthis
  oscillator, which are described in a laterchapter, via the
  OSCILLATOR EDIT menu.

  4848-

  0

  4848

  DETUNE 2 / 3DETUNE 2 / 3SHAPESHAPE / PW/ PWWAVE SELWAVE SEL
  SEMITONESEMITONE

  FM AMOUNTFM AMOUNTEDITEDIT SYNCSYNC SELECTSELECT

  OSC 3OSC 3OSC 2OSC 2OSC 1OSC 1

  0

  6

  1212 0

  6

  1212

  0

  6

  1212

  OSC 3OSC 3ONON

  WAVEWAVE

  OSCILLATORSOSCILLATORS

  AUDITIONAUDITION

• ACCESS VIRUS OS5 29The Third Oscillator

  THE THIRD OSCILLATOR

  The VIRUS also has a third main oscillator,which can be used to
  add more movement andbody to the sound. Oscillator 3 is activated
  us-ing the OSC 3 ON key, and its parameters be-come available after
  pressing the OSC 3selection button.

  Although the oscillator 3 parameters are no dif-ferent from
  oscillators 1 and 2, there is onething you should keep in mind.
  Because mostsounds only require two oscillators, the
  thirdoscillator has been made optional, i.e. it has tobe switched
  on whenever necessary.

  Oscillator 3 takes a certain amount of comput-ing power, and the
  trade-off is a reduction of themaximum polyphony: Playing a note
  using os-cillator 3 uses up about an extra third of a voicefrom the
  available polyphony. In other words:Playing a three-voice chord
  using a soundwhich includes oscillator 3 would use up four(and not
  three) of the available voices.

  THE MIXER SECTION

  You have already come across two parametersof the MIXER section:
  OSC BAL determines themix ratio between Oscillators 1 and 2; in the
  lefthalf of its control range, OSC VOL determinesthe master volume
  of the oscillator mix. In theright half of the control range from
  the centerposition to the far right, OSC VOL increases
  thesaturation intensity when a SATURATION curvehas been
  activated.

  Now well take a closer look at the final controlelement, the SUB
  OSC pot: It controls the vol-ume of the fourth oscillator, the
  so-called Sub-Oscillator, which always operates an octavebelow
  Oscillator 1.

  The SubOscillator is mixed to the Oscillator 1and 2 master mix
  signal as determined by theOSC BAL pot. The master volume of the
  com-posite mix is controlled by the OSC VOL pot.The only other
  parameter available for the Sub-Oscillator is accessible via the
  OSCILLATOREDIT menu where you have the option of select-ing a
  triangle or pulse waveshape (SUB OSCIL-LATOR WAVE
  SQUARE/TRIANGLE).

  The NOISE control determines the level of an-other basic audio
  source the noise generator.The other parameter belonging to the
  noisegenerator is its color, which can be set in themenu via NOISE
  Color in the OSCILLATOR-ED-IT menu. In the central position (+0),
  the noisegenerator produces so-called white noisewhich includes all
  frequencies at an equal level.Please note that, unlike the other
  oscillators,noise level is not affected by OSC VOL it iseven
  audible when this is turned down to zero.

  The fifth control in the mixer section determinesthe level of
  the Ring Modulator. This is not con-sidered one of the basic sound
  source, but isthe result of muliplying the output of oscillators1
  and 2. Ring modulation can create interestingenharmonic sounds
  which are highly dependantupon the frequency ratio between the two
  oscil-lators (adjustable via e.g. OSC 2 SEMITONE) aswell as the
  waveforms (e.g. use two sine wavesfor pure bell-like tones).

  To blend in the ring modulator use EDIT: RING-MODULATOR VOLUME
  (in OSCILLATOR EDITMenu). If the RINGMODULATOR VOLUME iszero, the
  ring modulator is switched off. OSCVOL does not affect the ring
  modulator level (orindeed the noise volume). Therefore the
  originaloscillator signal can be leveled independently of

• 30 CHAPTER 4Introduction

  the ring modulator. Be sure to check out whatthe ring modulator
  does when you select a sinewave for Oscillator 1 and 2.

  Now we can go on and solve the mysteries ofthe signal flow as
  determined by the FILTERROUTING operating mode SPLIT: Here
  Oscilla-tor 1 and the SubOscillator are routed to Filter-1, whereas
  Oscillator 2 and the Noise Generatorare routed to Filter-2.
  Although the soundsources are split into two signal paths, you
  canstill control the volume levels of the different el-ements as
  well as OSC VOL in the usual man-ner.

  THE LFOS

  When you first started this series of experi-ments with sounds,
  we promised that many ofthe functions the VIRUS can be programmedso
  that they are executed automatically. Youhave already learned how
  to control the volumeand cutoff frequencies of both filters as well
  asthe pitch and intensity of the frequency modula-tion of
  Oscillator 2 via preprogrammed enve-lopes. These options are great,
  but you havealready encountered a number of functionswhere it would
  be a helpful if you could alsoprogram them to be executed
  automatically.And of course envelopes are great modulationsources,
  but you have to play a note every timeyou want to initiate an
  envelope. During yourexperiments you probably came across a
  func-tion or two you would like to be able to controlperiodically —
  independently of notes. Somefeatures that come to mind are
  traditional tech-niques such as vibrato (periodic pitch control)and
  tremolo (periodic volume control). Anotheroption you might like to
  have at your disposal israndom parameter control.

  In the VIRUS, both of these tasks are executedby a so-called LFO
  (low frequency oscillator)that oscillates at frequencies below the
  audiblerange. An LFO is similar to the oscillators youhave
  encountered thus far, but it oscillates sig-nificantly slower so
  that its output signal is toolow for human hearing. So what good
  are they ifyou cant hear them? LFOs are used in muchthe same manner
  as envelopes, with the majordifference that the are repeated
  indefinitely.

  For our next experiment, you should recall ei-ther the basic
  sound you have always startedwith so far, or a version you have
  already editedand saved. Look for the RATE control in theLFOS/MOD
  section. To the left of this knob isan LED, which should be
  flashing in time withthe LFO 1 (the currently selected LFO see
  be-low). Turn the RATE control and see the speedof the LED
  changing. The buttons to the right ofthe RATE knob are used for
  selecting LFOwaveforms.

  The controls in the LFOS/MOD section only ap-ply to the
  currently selected LFO (like in the OS-CILLATORS section), and you
  can switch LFOsusing the SELECT button in the top lefthandcorner of
  this section. When LFO 3 is selected,the LED to the right of the
  RATE control flashesin time with LFO 3, otherwise it show the rate
  ofLFO 2

  LFO 1Start with the usual basic sound configurationor chose a
  modified sound to suit your taste.Locate the RATE pot in the LFO 1
  section of thecontrol panel. The RATE pot is equipped withan LED
  that indicates the speed of the LFO aswell as its waveshape. Turn
  the RATE pot andcheck out how the flash of the LED indicatesthe
  change of pace as you rotate the pot.

• ACCESS VIRUS OS5 31The LFOs

  Once you have pressed the lower SELECT-button button, you can
  scroll forwards or back-wards through the available modulation
  destina-tions with the PARAMETER buttons. When theEDIT key in this
  section is held down, modula-tion destinations can be selected by
  turning theSELECT control.

  Currently you are unable to hear the effect ofthe LFO as its
  modulation intensity is set to 0 inthe sound program. In order to
  change this set-ting, you must access the second SELECT but-ton
  which works in conjunction with fivevertically arrayed LEDs labeled
  OSC 1, OSC 2,PW 1+2, RESO 1+2, FILTER GAIN and ASSIGN:Press the
  SELECT button repeatedly and ob-serve how the LEDs flash in
  succession (theLEDs OSC 1 and OSC 2 flash separately as wellas in
  unison). The corresponding modulationtargets appear in the display,
  along with themodulation intensity values as determined bythe VALUE
  pot and VALUE buttons. (You can al-so scroll through the modulation
  targets via thePARAMETER button after you have pressed theSELECT
  button once.) Once you have dialed ina value other than 0 for a
  modulation target, thecorresponding LED illuminates continually.
  Thisfeature tells you at a glance that a modulation isunderway even
  when the display indicatessome other type of operation.

  HERE ARE THE DEFINITIONS FOR THE MODULATION TARGETS:

  — OSC-1 refers to the frequency of oscillator 1

  — OSC-2 refers to the frequency of oscillator 2

  — PW 1+2 means that the pulse widths of bothoscillators are
  controlled in unison

  — RESO 1+2 refers to the resonances of bothfilters. Please keep
  in mind that althougheach set of these parameters is assigned
  acommon modulation intensity, you can still di-

  al in different sound-shaping settings manual-ly. In other
  words, the audible result of a jointmodulation varies according to
  the valuesyou have determined for the other parame-ters.

  — FILTER GAIN This is the level of signal en-tering the filter
  section and therefore influenc-es the subsequent sa tu ra t ion s
  tage .Modulating FILT GAIN therefore causes a pe-riodic change in
  saturation as well as a tremo-lo i.e. a periodic change in volume.
  If thesaturation stage is not used, you will onlyhear tremolo. The
  position within the signalchain (at the input of the filter
  section) hasbeen deliberately chosen so that both the vol-ume and
  the amount of distortion can bemodulated by the same source, as is
  oftenthe case in electromagnetic instruments. Al-so, rapid LFO
  movements cause sharp im-pulses (transients) within the oscillator
  signal,which can be used to excite filter resonance.Filter
  resonance always dies away freely, asthe filter input is affected
  by modulating FILTGAIN, not its output.

  — ASSIGN Here you can freely select any mod-ulation
  destination.

  Modulate these five parameters separately andin combinations
  with different intensities. Try toanticipate the sound you will
  come up withwhen you modulate the first oscillator, the sec-ond
  oscillator or both oscillators at once andsee if the results match
  your expectations. Ifyou can fairly reliably predict the outcome
  ofyour sound-shaping efforts, you should have ahandle on the
  information discussed thus farand can use your knowledge to create
  specificsounds you have in mind.

  During the course of your experiments, it is en-tirely possible
  that you have generated modula-tions that have no effect whatsoever
  on thesound, for instance if you modulate the fre-quency of
  Oscillator 2 although it is dialed out

• 32 CHAPTER 4Introduction

  of the oscillator mix. When you run into thistype of problem,
  check out the signal routing, ifany configurations conflict with
  each other andmemorize the situation, problem and solution. Ifyou
  make a habit out of this, you wont panicwhen you run into similar
  situations; insteadyoull keep your cool, analyze the
  unexpectedsound and fix the mix.

  You are currently using a triangle as the LFOwaveshape. You
  shouldnt have any problemassociating the periodic up and down
  fluctua-tion of the target parameter with this wave-shape. Now
  activate the other avai lablewaveshapes for LFO 1 and try to
  picture the re-spective waveshape and associate it with theresults
  of the modulation.

  The third waveshape is a descending sawtoothwave. You can
  convert it into to an ascendingsawtooth by simply dialing in the
  requisite neg-ative modulation intensities (AMOUNT).

  In the WAVE setting, you have access to 64LFO waveshapes. Select
  these in the displaysection using the VALUE buttons:

  — S&H (Sample and Hold) is a structured ran-dom modulation.
  Here random modulationvalues are generated. The value is held
  untilthe next beat impulse, then it abruptly jumpsto a new random
  value.

  — S&G (Sample and Glide) is a continual ran-dom modulation.
  Here the random valuesglide seamlessly into one another, the rate
  ofwhich is determined by random modulation ofthe RATE value.

  The following 62 waveshapes are identical tothe oscillator
  sections digital waves. These canbe used to create interesting
  rhythmic effects.

  Continued your experiments with different LFOwaveshapes. Note
  that after a while you nolonger consciously hear minimal modulation
  in-tensities — depending on the waveshape andmodulation target
  (e.g. S&G +1 on OSC 1 or 2).However they do pep up the sound of
  lend it acertain vitality. The key to many great soundsare these
  types of minimal modulations.

  You may have gathered that the LFOs of the VI-RUS are
  polyphonic:If several notes are played simultaneously,these are
  controlled by dedicated LFOs, eachwith a slightly varied rate. This
  effect livens upthe sound of chords, especially when they
  aresustained. To enhance this effect, activate theLFO 1 KEY FOLLOW
  in the LFO-EDIT-Menu.

  This function enables you to control the rate ofthe LFOs via the
  pitch, or more accurately, viathe MIDI note number, so that higher
  notes gen-erate faster LFO rates. As result, when youpress and hold
  several notes you will hear allkinds of substantially different
  periodic fluctua-tions.

  Finally, the LFOs can also be used as additionalenvelopes. The
  control feature for this effect isthe ENV MODE button. When you
  press thisbutton, two things occur: For one, the LFO nolonger
  initiates its cycles periodically, but onlyonce at and in sync with
  the start of a note, andfor the other, the active range of the LFO
  isswitched from bipolar (in both directions fromthe zero position)
  to unipolar (from zero in onedirection only). Please note that this
  applies tothe modulation target but not the modulation in-tensity.
  Here you can still determine a value inthe entire bipolar
  range.

  This effect is especially prominent when used inconjunction with
  the sawtooth wave, which en-ables a fade-out type of effect (when
  you dial ina positive AMOUNT value) or a volume-swelltype of effect
  (negative AMOUNT) for the availa-ble modulation targets. Using the
  LFO Curve

• ACCESS VIRUS OS5 33The MOD Section

  parameter located in the LFO EDIT menu, youcan have the ramp
  rise or fall exponentially. Ifyou choose a triangle for your
  waveshape, thedevice will generate an ascending phase (at-tack) and
  a descending phase (decay). LFOCurve also lets you determine the
  temporal re-lationship between attack and decay; in otherwords,
  their respective rates.. Dial in the desiredspeed via the RATE
  pot.

  You can also use S&H and S&G in ENV MODEto come up with
  some attractive results: S&Hgenerates a single random value at
  the start ofa note (in this case, the RATE pot has no
  effect);S&G works in the same manner although in thiscase the
  RATE value is crucial. It determines theamount of time it takes to
  glide from the previ-ous to the new random value.

  THE MOD SECTION

  You may have noticed that, apart from the threeLFOs, an entry
  called MOD also appears as anoption when you press the Select
  button. Thisgives you access to the Virus modulation ma-trix. The
  six ASSIGN entries (selectable via theSELECT button) represent six
  freely definablemodulation connections. After you have select-ed
  one of them, you can set the modulationsource, destination and
  intensity in the menu.

  To maintain compatibility with previous Virusmodels, ASSIGN 2
  has two destinations andASSIGN 3 has three. Each of the other
  AS-SIGNs have only a single modulation destina-tion.

  Please note: When MOD is selected instead ofan LFO, the RATE
  knob will always control LFO1 by default.

  SOFT KNOB 1/2

  These are the two freely assignable controls.The destination of
  these controls can be de-fined within the Edit menu (SOFT KNOB
  1/2MODE). There are two parameters, one globaland one local i.e.
  applying only to the currentSINGLE program (which will override the
  globaldefinition if defined). SOFT KNOB 2 doubles asa value
  control, and therefore only works as aSOFT KNOB when the Virus is
  in Play mode i.e.no Edit menu is selected. For each SOFTKNOB, you
  can choose a short description froma list in the menu, and this
  will be saved as partof the SINGLE program. In Play mode, this
  willappear in the display to remind you of whateach SOFT KNOB does
  when you are playingyour Virus.

  (see The SOFT Knobs (Controls) on page 49).

  EDITEDIT

  AMOUNTAMOUNT

  ASSIGN 1ASSIGN 1

  ASSIGN 4ASSIGN 4

  1 2 / 32 / 3

  ASSIGN 2ASSIGN 2

  ASSIGN 5ASSIGN 5

  ASSIGN 3ASSIGN 3

  ASSIGN 6ASSIGN 6

  MODMOD

  FILTER 2FILTER 2

  PW 2PW 2

  PANPAN

  ASSIGNASSIGN

  SYNCSYNCPHASEPHASE

  SHAPE 1+2SHAPE 1+2

  OSC 1OSC 1

  FM AMTFM AMT

  OSC 2OSC 2

  FILTER 1FILTER 1

  PW 1PW 1

  OSC 1OSC 1

  OSC 2OSC 2

  PW 1+2PW 1+2

  RESO 1+2RESO 1+2

  FILT GAINFILT GAIN

  ASSIGNASSIGN

  0

  6

  1212

  SELECTSELECT

  WAVEWAVE

  LFOS / MODLFOS / MOD

  321 MODMOD

  LFO 1LFO 1

  LFO2LFO2

  LFO3LFO3

  RATERATE SHAPESHAPE

• 34 CHAPTER 4Introduction

  VOLUME AND PANORAMA POSITION

  You probably noticed that the many of thesound shaping options
  available in the VIRUSoccasionally influence the volume level. For
  in-stance, an unfiltered sawtooth is naturally loud-er than a
  highly filtered sawtooth becausewhenever you blend a part of the
  frequencyspectrum out of the mix, you are automaticallyreducing the
  overall volume of the signal. This iswhy the VIRUS is equipped with
  a programma-ble volume pot for each SINGLE PROGRAM. Itenables you
  to balance out the volume levels ofyour sound programs.

  Locate the parameter PATCH VOLUME in theCOMMON section of the
  EDIT menu.

  01111111111111111112

  1 COMMON PatchVolume 100 61111111111111111154

  Its value is set to 100 so that you have a reserveor headroom of
  27 volume increments whenyou are dealing with highly filtered
  sounds.

  You have already dealt with the Panorama posi-tion as a
  modulation target of LFO 2. Here youcan not only modulate it, but
  also determinesettings manually. For this purpose, use the
  pa-rameter PANORAMA which is also located inthe OUTPUT section of
  the EDIT menu. Likemany other parameters, Panorama is a
  startingpoint for modulations. For instance you canmodulate the
  Panorama position via LFO 2even if you have already set the
  Panorama tothe far left position. In this case of course youwill
  only hear the Panorama position shift to theright.

  VELOCITY

  Velocity is one of the preferred modulationsources of keyboard
  players: A light key attackgenerates a low velocity value for the
  givennote, a heavy touch generates a high velocityvalue. In the
  VIRUS you have ten modulationtargets available for Velocity. Locate
  the VE-LOCITY section in the EDIT menu.

  01111111111111111112

  1 VELOCITY Osc1Shape +061111111111111111154

  There you will find the modulation intensitiesfor:

  which you can manipulate independently of oneanother in the
  familiar bipolar control range.

  A light key attack generates a low velocity valuefor the given
  note, a heavy touch generates ahigh velocity value.

  OSC 1 SHAPE

  OSC 2 SHAPE

  PULSE WIDTH

  FM AMOUNT

  FILT 1 ENV AMT

  FILT 2 ENV AMT

  RESONANCE 1

  RESONANCE 2

  VOLUME

  PANORAMA

• ACCESS VIRUS OS5 35Unison Mode

  UNISON MODE

  When we talked about the oscillators, we men-tioned that by
  subtly detuning signals, you canbeef up sounds and achieve
  string-like sounds.The VIRUS is equipped with features that
  allowyou to take this type of tonal manipulation astep further. On
  of these is the so-called UNI-SON MODE. It enables you to initiate
  two ormore voices for each note played, which in turnlets you
  detune many oscillators. UNISONMODE also offers the option of
  spreading thevoices generated by one note in the stereo pan-orama
  and shifting the phases of their LFOs sothat all types of periodic
  effects can be used toproduce an even more exciting signal.

  Locate the parameter group UNISON in the ED-IT menu.

  01111111111111111112

  1 UNISON Mode Twin 61111111111111111154

  UNISON mode determines how many voicesthe VIRUS will use to
  render a played note. In anutshell, it determines how fat the sound
  willbe. You can use the UNISON Detune parameterto determine to
  which extent the active voicesare detuned. UNISON PanSpread
  distributesthem uniformly across the stereo panorama, aprocess by
  which you can also determine thewidth of a sounds stereo base. When
  you acti-vate UNISON mode for a sound, it can still beplayed
  polyphonically. However, depending onthe number of voices youve
  dialed in, its po-lyphony will of course be considerably reducedin
  UNISON mode. The most efficient and thestandard setting is UNISON
  mode = Twin,

  where two voices are played for every note. Inthe OFF position,
  one voice per note isplayed.

• 36 CHAPTER 4Introduction

  THE EFFECTS

  At the bottom left of the panel is the effectssection, divided
  into an EFFECTS and a DELAY/REVERB block. This gives you access to
  Distor-tion, Phaser and Chorus effects as well as De-lay and
  Reverb.

  The TYPE/MIX and INTENSITY knobs in the EF-FECTS block are used
  to control the distortion,phaser and chorus effects. They always
  applyto one of the three simultaneous effects only,selectable via
  the Select button. The followingparameters can be controlled using
  these twoknobs:

  All other effects parameters are defined in themenu by pressing
  the upper EDIT button.

  The lower EDIT button in the DELAY/REVERBsection lets you switch
  between the Delay andReverb effects. The SEND control determinesthe
  proportion of the selected effect within thesignal; DELAY/REV TIME
  controls Delay time or

  Reverb decay; FEEDBACK/DAMPING deter-mines the degree of
  feedback in the Delay sig-nal, or high frequency damping for the
  Reverb.

  If Delay or Reverb are synchronized to theclock, DELAY/REV TIME
  controls the time ex-pressed as a note value (1/16, 1/8, etc.).

  In the next section we are going to take a closerlook at the
  Virus effects.

  DISTORTIONThe Distortion effect is actually a collection
  ofseveral different algorithms, which are selecta-ble via the
  TYPE/MIX control:

  — OFF No distortion

  — LIGHT, SOFT, MIDDLE, HARD Four analogdistortion curves, with
  differing characteris-tics and intensities.

  — DIGITAL Digital distortion with hard clipping.

  Shaper. Sine characteristic with multiple wavecycles. Signals
  sent through the Shaper canbe changed quite drastically; the
  results areoften similar to the spectra of linear FM (fre-quency
  modulation).

  — RECTIFIER Variable half-wave rectification;input level does
  not affect the amount of dis-tortion.

  — BITREDUCER Variable reduction of the bitdepth; generates
  digital quantization noise.

  Distortion-Effekt:

  TYPE/MIX Distortion Curve

  INTENSITY Distortion Intensity

  Phaser-Effekt

  TYPE/MIX Phaser Mix

  INTENSITY Feedback

  Chorus-Effekt:

  TYPE/MIX Chorus Mix

  INTENSITY Depth

  EDITEDIT SELECTSELECT00

  66

  12121212

  EFFECTSEFFECTS

  DISTDIST

  TYPE/TYPE/MIXMIX

  PHAPHA

  CHOCHO

  INTENSITYINTENSITY

• ACCESS VIRUS OS5 37The Effects

  — RATEREDUCER Variable reduction of thesampling rate; generates
  digital aliasing ef-fects.

  — LOWPASS 1-pole lowpass filter; gentle re-duction of higher
  frequencies.

  — HIGHPASS 1-pole highpass filter; gentle re-duction of lower
  frequencies.

  The INTENSITY control is used for setting thedegree of
  distortion (in distortion algorithms) orthe cutoff frequency (in
  the two filter algo-rithms). INTENSITY ranges from very slight
  toextreme.

  PHASERThe Phaser effect produces resonant (or evencutting)
  emphasis on certain frequencies withinthe signal. The frequencies
  of these resonancesare shifted around the frequency
  spectrum,causing a distinctive movement in the sound.Tastefully
  applied, this effect is particularly goodfor pad sounds and for
  authentic traditionalelectric piano sounds.

  The pure Phaser signal is the result of a fre-quency-dependent
  phase shift together with aslight pitch modulation from the phasers
  ownLFO. Typical phaser sounds only appear whenthe processed signal
  is mixed with the dry sig-nal, usually at the same level. The
  TYPE/MIXcontrol is used to set this balance.

  The INTENSITY control changes the level offeedback in the phased
  signal. Higher feedbacklevels cause higher resonant peaks in the
  sig-nal. The FEEDBACK parameter is bipolar, be-cause positive and
  negative feedback havedifferent characteristics.

  More phaser parameters can be found in theEDIT menu: RATE and
  DEPTH control thespeed and intensity of modulation from the

  phasers own LFO. The other three parametersaffect the general
  sound of the phaser: FRE-QUENCY determines the average frequency
  ofresonant peaks, STAGES is the number of reso-nant peaks and
  SPREAD is the distance be-tween resonant peaks within the
  frequencyspectrum.

  CHORUSChorus has been a popular effect for a longtime, and is
  often used to make pad sounds(such as synthetic strings) less
  static. It is actu-ally a pair of short delay lines (usually no
  longerthan 50 ms) with continuously modulated delaytime via
  dedicated LFO. This modulation caus-es subtle frequency shifts in
  the processed sig-nal, which results in a more complex
  phasingbetween direct and processed signals. Feed-back in the delay
  line accentuates the Choruseffect, and because the left side of the
  signal ismodulated in the opposite direction to the rightside, the
  Chorus effect is capable of creating astereo signal from a mono
  input.

  When the basic delay is extremely short, this ef-fect is called
  flanging. The feedback parameteris especially significant here, as
  higher valuescan create dramatic resonances and couldeven be
  considered an additional signal source.Like in the Phaser, the
  FEEDBACK parameter isbipolar, because positive and negative
  feed-back have different characteristics. At higherfeedback levels
  (negative or positive) it be-comes obvious that the two sides of
  the signalare being modulated in opposite directions.

  The TYPE/MIX control in the EFFECTS sectiondetermines the
  balance between the direct andprocessed signals. The RATE and SHAPE
  pa-rameters control the dedicated LFO, and areavailable in the EDIT
  menu. Two further parame-ters in the menu are DELAY and
  FEEDBACK.These are used to set the delay time and feed-back level.
  The INTENSITY control determines

• 38 CHAPTER 4Introduction

  the DEPTH i.e. modulation intensity of the LFO.Please note that
  signal paths in the Virus Cho-rus/Flanger are stereo throughout:
  The stereoposition and any panorama modulation or ster-eo spread
  values are preserved in the proc-essed signal.

  DELAY/REVERBThe DELAY/REVERB section is responsible fortwo
  different effects. The SEND control deter-mines the relative amount
  of effect signal:

  The DELAY effect delays the input signal, and isusually used for
  echoes. The nominal delay timeset by the DELAY/REV-TIME control can
  bemodulated so that stereo phasing effects canappear. The delay
  time can be synchronized tothe clock so that echoes will be in time
  andwill automatically adjust to any tempo changes.There are also
  several fixed-pattern delay algo-rithms, many of which delay the
  left and rightsides differently i.e. using different note
  values.Interesting rhythmic patterns can be created byincreading
  feedback level (via the FEEDBACK/DAMPING control).

  REVERB simulates the effect of the boundariesin real spaces such
  as living rooms or cathe-drals. There are several parameters here
  whichgo beyond pure simulation of real spaces. Thepredelay
  parameter normally found in reverbunits is handled by the DELAY
  section de-scribed above DELAY is in front of REVERB inthe signal
  path. REVERB can be synchronizedto the clock so you can seamlessly
  integrate theeffect into the rhy

150

CHAPTER 12

Tips and tricks

patch just the pure effect signal of a MULTI Part

through as you would it you were using a con-

ventional dry/wet effect knob.

01111111111111111112

1 DELAY

EffectSend

61111111111111111154

DELAY/REVERB OUTPUT SELECT

The DELAY/REVERB Output Select function

lets you send the DELAY/REVERB section’s

output signal to any mono or stereo outputs. If

you patch the DELAY/REVERB signal to a virtu-

al aux bus, it can be processed further by

means of a MULTI Part that taps into this aux

bus (INPUT Select), and even routed back into

the into the DELAY or REVERB via the same

PART’s effect send loop, which generates feed-

back. With this feedback circuit, you can filter

and trigger the DELAY/REVERB signal, modu-

late its volume and even lay chorus over it.

When you’re working with feedback, be sure to

keep a watchful eye on the signal level. The DE-

LAY/REVERB section’s level can easily rise to

an intolerable volume (e.g. when the level is

cranked up by a filter resonance) when the

amount of feedback that you have dialed in is

too great.

í

THE VIRUS AS AN EFFECT

DEVICE

You’re free to install the VIRUS into your studio

environment and use it as an effect device or

signal processor. For example, simply connect

its external inputs to any available aux send bus

or effect send on your mixer or to the individual

outputs of a sampler or other sound generator.

This setup lets you mix sundry signals outside

the VIRUS and patch the mixed signals into the

VIRUS for further processing.

73≤

.. AND VICE VERSA

SECOND OUTPUT Balance lets you create a

separate mix in the VIRUS itself. This signal

may then be patched out via the selected out-

put (SECOND OUTPUT Select) to a mixer or di-

rectly to a connected effect device, where it can

be processed further.

Alternatively, this mix can also be routed to an-

other PART of the VIRUS, where, for example, it

can be filtered or distorted. For this purpose, be

sure to select the same aux bus for SECOND

OUTPUT Select and for the INPUT Select of the

given PART.

í

ENVELOPE FOLLOWER

This function of the VIRUS is a special delicacy.

It really upgrades the process of filtering (or any

other processing) of an external audio signal.

What we have here is a so called Envelope Fol-

lower that can evaluate the volume envelope of

an external audio signal with a selectable speed

or inertia and then creates an appropriate mod-

ulation signal. This signal can be used to control

any VIRUS parameter via the Modulation Ma-

trix. In UNISON Mode the Envelope Follower

works in true stereo, you can find the parame-

ters in the effects menu under INPUT. One ex-

ample for its application: A drumloop serves as

the external signal; the Envelope Follower con-

Although the Access Virus features one of the most knobby control surfaces amongst virtual analogue synths, there’s a lot of programming flexibility available which isn’t immediately obvious. We show you how to uncover the hidden possibilities…

The Access Virus is one of the more successful virtual analogue synths, and its ballsy, punchy sound has been enthusiastically adopted by musicians working in a wide variety of musical styles. However, for programmers and sound designers this isn’t the easiest synth in the world to get to grips with. The fact that there are knobs on the panel is deceptive, because they control fewer than half the available parameters. Getting to the rest needs either a computer-based editor or a good head for menu navigation and a sturdy index finger. In this article I’ll be offering a number of hints and tips for programming the Access Virus B specifically, but because the Virus has changed relatively little, most of this advice also applies to other models, from the earliest Virus A onwards.

The basic editing principle is simple. Each section — oscillators, LFOs, filters and main control — has its own separate Edit button. These buttons don’t interact (in other words, Access didn’t choose to make them link into a single very long menu list), but if you remember that the only way to get to some of the parameters is through the different Edit buttons, you won’t go wrong. For overall instrument control, use the Ctrl button, which sets various global parameters. All the other Edit buttons are patch specific.

The other confusing feature is display snap. Whenever you alter one of the knob settings, the display changes to show that parameter. Then it snaps back to whatever was being shown before. This can be confusing initially, but after a while it starts to make enough sense to be usefully informative.

Oscillator Basics

With those basics in mind, let’s take a closer look at the oscillators. These have been designed to produce both digital and analogue effects. But they can leave programmers quivering with confusion, because the shaping options are controlled by just two knobs, the functions of which are completely misrepresented in the manual. Figure 1 is a block diagram showing how the controls really work. What you get are three sources, crossfaded by the Shape knob: at 12 o’clock there’s a static sawtooth; at the maximum anticlockwise setting there’s a wavetable oscillator; and at the other extreme there’s a pulse oscillator. The Wave Sel/PW knob does double duty, controlling the waveshape for both the wavetable and pulse sections. The sawtooth, meanwhile, is completely static, and no amount of Wave Sel waggling or modulation will ever change it.

One obvious limitation of the way the controls work is that you can’t hear pulse and wavetable outputs together — perhaps not a major drawback, but it’s as well to be aware of it. Another ‘gotcha’ is that the pulse-width range available via the Wave Sel knob is limited to 50-100 percent, rather than the 0-100 percent range you might want. The only way to get the full range is to add modulation from the envelopes or LFOs using the modulation matrix, of which more in a moment.

Wavetable Synth Effects

So, as a rule of thumb, the best way to get interesting effects from the oscillators is to leave the Shape parameter alone, usually at one extreme or the other. If modulation is going to be used, apply it to Wave Sel only. At the digital extreme, it’s worth taking some time to set up a manual sweep so that you can note down which wave numbers sound the most interesting. For example, waves one and two are sine and triangle respectively; wave 64 is good for vibe and marimba effects; wave 14 is a good organ tone; and wave 57 has a fifth mixed in, which makes it good for solos. When used with some low-pass filtering, many of the waves are good raw material for DX-like percussive sounds, and electric pianos are also easy to create. (Note that there are no good vocal waveforms, but as we’ll see later there are ways around this shortcoming.) Treating the Virus as a simple single-oscillator synth offers a wide enough sonic universe that it really is worth taking the time to get familiar with the raw materials available here.

The wavetables step very obviously while scanning, and lack the smooth changes between closely related tables available in some PPG-type instruments. But more coarse timbral stepping effects can still sound interesting. For example, routing the velocity values of MIDI Note On messages to Wave Sel is a quick and effective way to add timbral control to sequences and bass lines. (It’s not so useful for manual control, unless you have the exquisitely toned and sensitive fingers of a top classical pianist, with a controller keyboard to match!) For a more extreme effect, you can use the velocity values of MIDI Note Off messages to add extra stepped changes within each note, so that the timbre changes when you release a key.

A worthy challenge is to create evolving Wavestation-like pads. Because the wave selection is stepped rather than continuous, you can’t do this by modulating Wave Sel. But if you set the three oscillators to different fixed digital wave shapes you can then use the LFOs or the envelopes to crossfade between them — not as complex an effect, but one that can still sound good with careful fine-tuning.

At the virtual analogue end of the Shape control’s travel you can create some very punchy effects in the time-honoured analogue way by patching an LFO or envelope to control pulse width. This routing sounds particularly good on the Virus, and no owner should be without at least a couple of patches that do this. You can also mute an oscillator to match a beat by sending its pulse width to the 100-percent extreme with an LFO. Use a square LFO waveform to switch it on and off, or other waveforms to fade it. This sounds mind-bendingly extreme if you patch each LFO to a separate oscillator, and detune oscillator two up by a musical interval such as a fifth (+7 semitones). A less extreme effect is to detune the oscillators by a small amount and use this technique to add movement as the oscillators fade in and out, changing pulse width as they do so.

Modulating Shape offers fewer possibilities than modulating Wave Sel — which means you’re usually best off ignoring the fact that Shape is one of the default destinations available on LFO2. But it can be interesting to crossfade between digital and analogue wave shapes using the envelopes, perhaps creating a sharp percussive digital ‘donk’ at the start of a note, and ending with an analogue tail. This can work well if you leave Wave Sel fixed. Trying to sync Shape modulation with Wave Sel changes can easily get unwieldy, and it takes a rare level of persistence and adventurousness to create listenable patches that rely on both effects. But as we’ll see below, the LFOs have a few tricks that make Shape modulation more useful than it would be otherwise.

Getting The Best From Multiple Oscillators

Oscillator two is just like oscillator one, but with extra Semitone and Detune settings. Also available are FM and Sync options. Sync works as you’d expect. One handy tip is that oscillator one has its own Semitone setting buried inside the oscillator Edit menus. Using this, you can tune it down a couple of octaves. Now when you select Sync, oscillator two can provide some very rich and broad static timbres depending on the relative pitch offset. Mix in the output of the sub-oscillator, and you have a very impressive sub-bass. You can create all the usual ripping sync effects by modulating the frequency of oscillator two with either an LFO or one of the envelopes.

Generating clearly-pitched FM tones using the Virus’s FM Amount control can be tricky, as it sometimes lacks adequate resolution, so you sometimes also need to use the Detune control to find the sweet spot.The FM feature is more complex than Sync, with more sources to choose from. As with Sync, the destination is always oscillator two, but the source can be oscillator one’s wave, noise, or an external input. Oscillator one’s Tri, Pos Tri, and Shape (which uses the digital output controlled by Wave Sel) options speak for themselves, and the best way to hear the differences between them is to try them. Each has a different sweet spot, where the FM Amount setting aligns all the overtones in a way that eliminates beating and produces rich and reedy timbres instead of clangy ones. Sometimes the FM Amount resolution is too coarse to find this sweet spot exactly, and when that happens you can use oscillator two’s Detune control to compensate. If you want clangy effects or ones with lots of beating, you can create them using the Semitone, Detune, or FM Amount knobs in any combination. Note that you can also control FM Amount using the envelopes. This can sound a tad too abstract, in a Dr Who kind of a way, for pads, but it can add a hint of extra punch and slap to bass sounds and leads.

An unusually interesting source for FM is the noise setting. This adds a kind of filtered noise effect around the pitch of oscillator two, and is good for grungy, dirty, quasi-distorted noises. Small FM Amount settings add an interesting hint of this. At large settings the sound falls apart into something that sounds like distortion of extreme nastiness. The sound responds to the Noise Color setting (also in the oscillator Edit menu), and negative settings have much more low-end rumble. If you detune oscillators one and two as low as they go, you get stepped transients which can trigger classic random analogue blips if fed to the filters with the Resonance knob turned up. Turning on Sync and dialling in extreme modulation of oscillator one with plenty of noise on oscillator two creates huge sheet-like ripping sounds. In between there’s a range of timbral possibilities which is ideal for grungified distorted solo sounds. The FM section also includes two external stereo inputs. You can mix either of the two stereo inputs to mono sums, or select any of the four inputs separately, and then feed them into this section. Vocals work surprisingly well here, assuming you like industrial music — delicate processing for ballads is not this feature’s strong point!

Hiding out of sight in the oscillator section are oscillator three and the sub-oscillator. The latter is a very simple low-end fattener, one octave down from oscillator one, with either square or triangle waveforms. A panel knob in the oscillator mixer section lets you set the level. Oscillator three will either follow oscillator two’s settings if Slave is selected, or can be used as a spare extra waveform. FM and Sync don’t affect oscillator three, so you can use oscillator two for richness and distortion while filling out the body of the sound with oscillators one and three. Note that using oscillator three cuts down polyphony by around a third — there aren’t many situations where it makes a life-and-death difference to the size of the sound, so for patches you plan to use multitimbrally its use is perhaps best considered an optional extra.

Taming The Filters

The basic details of the Virus’s various filter modes and patches are described comprehensively in the manual, and there’s no need to repeat them here. Less well known are some of the effects that are unique to a dual-filter design and aren’t based on the classic filter opening/closing effect.

Eliminating Muddiness: Too many patches based on low-pass filters can make the low end of your mix sound muddy. A static high-pass filter in series with a low-pass filter can remove some of the obesity, adding clarity to pads, leads, and even bass lines. Just set filter two to work as a high-pass filter, and put it in series after filter one. Then move the cutoff of filter two upwards until you get rid of the low-end bloat.

Aside from some dance styles and music with ultrasonic effects, most music benefits from having the low end tidied up. This can help preserve detail and avoid synth mush, especially when blending a lot of analogue-like patches. It can even allow you to maximise the apparent level, because faithfully reproducing deep sub-bass frequencies takes a lot of dynamic range for little subjective impact. It can even be worth tidying up the low end when you don’t have the oscillators tuned low. This is because the envelopes on the Virus are fast enough to produce near-DC clicks, pops, and thuds. Sometimes you want to leave these in because they add extra punch to sounds, but when you don’t a high-pass filter is a good way to get rid of them.

You can clear up low-end muddiness using a high-pass filter: first set filter two to its HP mode (top inset), then select a series routing from the filter section’s Edit menu (bottom inset), and finally adjust the cutoff by ear (right). Pseudo-phasing: Most synth users understand how a filter’s frequency curve changes, but it’s not so widely known that a filter produces frequency-dependent phase changes as well. Overlaying two filter curves produces more than the sum of the individual responses, and sweeping either or both can create Jarre-like phasing effects that vary depending on which filter modes you use. This isn’t true phasing, which relies on multiple notches in the frequency response. But it can produce some very fine swishes and washes, and can work particularly well combined with vamped chords from the arpeggiator. Use the Par 4 mode for this, with one filter set to low pass or band pass and the other as either high pass, band pass, or band stop. You can manually experiment with the effect by using the Cutoff 2 knob which, as the manual explains, controls the offset between the two filter frequencies and is not — as you might think — an independent cutoff setting.

Vocal Formant Effects: High-quality vocal formant synthesis needs at least three filters, and for the best possible results five. But you can still create some interestingly vocal-like effects using just two filters if you set things up very carefully. The first step is to create some speech-like raw materials. The vocal chords make a buzzy clicking sound very like a thin pulse, so begin with a single oscillator, setting Shape to its maximum value and Wave Sel/PW to around 115. Then set both filters to band-pass, mode to Par, resonance to around 90, and filter keytracking to zero percent. You’ll get a range of vowel sounds by setting both Cutoff controls between 50 and 70 — experiment for best results. For an even more expressive effect, patch the mod wheel to the Cutoff 2 control. You can then play the vowels as you play the keyboard. The effect only sounds believable over a low 2-3 octave range, and works best as a solo voice. If you patch velocity to Cutoff 2, you can control the vowel sounds from a keyboard (interesting, but tricky to play…), a sequencer, or the built-in arpeggiator.

Saturation: Although this is controlled with the oscillator Volume knob, the saturation is part of the filter section and you can set its characteristics from the filter section’s Edit button. The Virus offers a range of saturation types, from basic rounding to digital decimation. These are best experienced rather than described. Many add a hint of digital fizz that isn’t always welcome — it’s a quirk of the Virus that for analogue simulations you’ll often get the best and fattest sound by leaving saturation turned off.

Hidden LFO Power

Like the other features of the Virus, the LFOs have plenty of hidden subtleties that can baffle the novice and delight the adventurous sound designer. The basics seem straightforward enough — two LFOs with the usual selection of wave shapes and destinations — but the Wave LFO setting is one of the secret weapons in the Virus arsenal. Pressing the Shape button on the panel shows the wave selector. This offers standard stepped sample and hold (S&H), smoothly varying sample and glide (S&G), and access to all of the digital waveforms that are available in the oscillator section. This might not sound like a big deal, but the Virus really comes alive when these digital waveforms are used as modulation sources. They’re particularly useful for controlling the amplitudes of the oscillators in various combinations, and for complex filter sweeps. The standard sine, triangle, and ramp waveforms sound predictable and uninteresting in comparison. (As a side note, if you see a Virus with LFO LEDs flickering apparently randomly, it’s likely that the LFOs have just been set to produce the digital oscillator waveforms.)

When combined with the arpeggiator, it’s easy to use these waves to create complex but solidly rhythmic textures that evolve as notes are held down, these patterns spanning anything from a fraction of a beat to entire bars. As with the oscillator section, it’s well worth taking the time to audition these waves to see what kinds of effects they can create when used as modulation sources. For example, wave 47 is a double ramp, and is particularly good for rhythmic modulation. Some of the other waves change very quickly, which means they’re best used at very slow LFO rates. Unfortunately there are no wave graphs in the manual, and so far as I could find they’re not listed anywhere on-line either.

The most interesting LFO effects available on the Virus are to be found by selecting the Wave option, which gives the LFO access to all the main digital oscillator waveforms. You can then use the MIDI sync functions in the LFO section’s Edit menu to create useful tempo-based rhythmic effects.These more complex waveforms work particularly well when you combine them with MIDI sync. By default LFO timings are absolute, but if you change the Clock setting, within the LFO Edit menu, you’ll see a range of MIDI clock dividers, from tiny fractions of a beat to 16 bars (shown as ’16/1′). The wide range is there to accommodate some of the more frenetic modulation shapes. With a little thought it’s easy to create very complex but stable rhythmic effects by locking both LFOs to MIDI clock, setting each one to a different subdivider and waveshape, and then routing them to Wave Sel, filter cutoff frequencies, the levels of each oscillator, the pitch of oscillator two when the Sync button is turned on, and so on. But how to make these connections? The selection of default assignments available from the panel is more than a touch random. Oscillator pitch is obvious enough, but LFO control of filter resonance isn’t quite so useful and, as we’ve seen, control of oscillator Shape is less useful still. Fortunately, the Assign option provides a much wider range of destinations for both LFOs.

Clicking the button repeatedly steps down the list of destinations on the panel. When the Assign LED turns on, ‘Dest’ appears in the edit window. Now you get a huge range of destinations to choose from, including almost all the programming parameters the Virus has to offer. Aside from conventional patching possibilities (pitch, filter cutoff, and so on) there are also more adventurous destinations, such as the envelope timing parameters and arpeggiator controls. You can also modulate effects settings, such as delay time and reverb mix. You can even make the LFOs modulate each other, for chaotic and unpredictable effects.

When you combine complex waveforms with MIDI sync and this very rich selection of modulation routings, you can add another level of movement to rhythmic patches, or create very fluid and interesting slowly evolving pads and abstract tones. The patching possibilities rival those of a medium-sized modular, but with the advantages of MIDI sync, polyphony, and patch memories. It’s perhaps best to explore these combinations without too much direction from a feature like this one. The basic principle of using unusual LFO waveforms with MIDI sync and perhaps the arpeggiator gives you plenty of scope for colourful sound creation. As with a real analogue synth, exploring the possibilities makes finding some trademark programming effects and a signature sound more likely.

Arpeggiator Tricks

And what about that arpeggiator? By default it has the usual selection of modes: up, down, random, and so on. These aren’t very exciting, but using the Pattern parameter brings in a range of rhythmic repeats that spice up the sound and make it much more interesting. There are 64 of these (if you have an older OS you’ll find fewer available — you can get the rest by upgrading) and they use the same clock divider system as the LFOs, so it’s easy to create MIDI sync. At very fast subdivisions, such as 1/64, you can create whirring distorted effects.

If you switch the Arpeggiator to its fastest Clock setting, you can generate whirring, buzzing distortions.The arpeggiator also hides a secret, which is that notes in each pattern include velocity information. So patching velocity to filter cutoff, Wave Sel, or some other timbral parameter can produce some wonderfully dynamic rhythmic effects. As a good rule of thumb, most patches with a fast attack sound good when arpeggiated this way, and it’s worth spending a productive hour or two trying out arpeggiation on all the presets that don’t have it already. The top 30 patterns or so include twiddles, legato glides, and burrs designed to add interest to dance music. Many of these sound best in one of the Mono modes, and turning manually-controlled portamento on can create some very TB303-like acid effects.

Using the arpeggiator in Multi mode can easily create monstrous arpeggios of ultimate doom! The trick here is to try to use patches and pitches that are distinct enough to be heard clearly. You can also add basic rhythm by filling out the sound with arpeggiated bass drum, snare, and hi-hat patches — the latter especially can benefit from some of the more intricate patterns that are available.

Effects & Processing

The effects section of the Virus is an understated beast. Each voice in the Virus C has its own completely independent effects chain, with phaser, chorus, delay/reverb, and three-band EQ. Although you can use these effects just for adding gloss to your synth sounds, it’s more interesting to include them within patches in a more organic way. The key here is the modulation section buried deep inside the main Edit menu. This works like the LFO assignment section, but is independent of it and offers a much wider range of sources, including various MIDI controllers, velocity, and also the envelope outputs. The destinations include most of the parameters inside the Virus — including many effects control parameters.

This means, for example, that you can use an envelope or one of the continuous controller channels to control delay time or phaser frequency. A good start is to experiment with adjusting the effects using the synth section’s modulation sources. Doing this will give you a whole new palette of sounds and effects you probably never expected to hear from a synth.

And finally, there’s external processing to think about. Access have made it easy to assign external inputs to oscillator control for FM, to the ring modulator, and of course to the filters. The big attraction in the last case is that this will also route audio through the effects section, so you can use filtering and level control at the same time as adding delay effects and chorus — ideal for chopped up dance pads, for example.

But perhaps the most impressive effect which uses the external inputs is the vocoder. The manual does a good job of explaining how this works, and if reading about it doesn’t make it clear, practice soon will. What’s not so obvious is that the vocoder parameters can be programmed and sequenced via MIDI using the standard Virus panel assignments. This gives you total control over spread, bank offset, resonance, and all the other ingredients of the vocoder sound, and setting up rhythmic MIDI control can create some extremely dynamic and unusual effects. If you have a MIDI processor like Cycling 74 Max/MSP or Emagic Logic, you can even route the output from the arpeggiator to these parameters in real time.

Super Bug!

It’s likely that many Virus owners aren’t using their synths to maximum effect. However, unlike other synths where intensive patch programming produces sounds that are more gimmicky than interesting, the Virus is an extremely musical product and will enthusiastically repay an adventurous approach.