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Access Virus Overview - Are You Still Infected?

Synth Morph access virus synthesizer review synthesizer tutorial


Late nineties was an exciting time for musicians: the virtual analog / wavetable evolution based on DSP chips running software code started in 1995 with the Nord Lead, then followed by a number of competitors: Access Virus A (1997), Waldorf Microwave II/XT (starting in 1997), Novation Supernova 2 (1998), Roland JP 8000 (1997) and Yamaha AN1X (1997). They all became legends at that time, and these instruments and their newer reincarnations (like Nord Lead 2x, 4, Blofeld, Nave, Virus TI) all involves a kind of 'magic' and 'charm' that made them very popular and are being used to this day. Probably developers may tell us the most about what made their sound so appealing, but in the next parts I'll try to answer some of these reasons by focusing on the Virus B and Virus C models. Why to talk about these 'oldies'? Though the technology behind is around 20 years old now they are still absolutely not outdated sound-wise or as musical instruments themselves. 

Creator of the Virus

German inventor Christoph Kemper of Access Music is a visionary: together with his team he managed to create a family of musical instrument that has a steady foundation for twenty years, yet expanding the basics of the Virus with an amazing feature set that raised the Virus into an unrivaled super-instrument. Just shortly mentioning The Virus TI here, it grew significantly: has much more effects (especially the per part reverb and delay), new synthesis methods, new filters, character algorithms, more envelopes, radical arpeggiator improvements, double the amount of mod. matrix destination compared to Virus C, updated D/A converters, (occasionally glitchy) computer integration and a bit of improved polyphony. Contrary to the public opinion the TI is a quantum leap forward in terms of features and usability even if it includes 100% the very same DNA of the Virus A that made these instruments so famous.

Access Virus creator Christoph Kemper

The business model of Access Music is unique and fruitful in the music industry: a premium product at a premium price, where free firmware updates add major new incremental features and expand the sound palette, while maintain backward compatibility and the basics kept untouched. Can you pick any other digital synthesizer company that sells a product now that builds one-hundred percent on something (Virus A) that started 20 years ago?

As he mentioned in an interview, instead of modeling existing analogue parts his process of creating and fine-tuning was the 'listen and tune' method. So all sound components were tuned to human hearing, finding the sweet spots that people find enjoyable to the ear and emphasizes the music character. This approach certainly contributed to the persistent success of the Viruses. 

'The Trance Machine'

In the late nineties the Virus b was clearly aimed at the very popular trance genre at that time, thanks to some awesome 3rd-party trance soundsets (factory presets were great too but geared toward a more general usage). These preset designers created a cool sonic aura you did not hear from synths earlier, and folks started to associate the sound of Virus B / C and their variants to trance / dance music at that time. Viruses became incredibly popular, this 'hitmaker' instrument appeared in everyone's setup. Hence, the decline of that classic millennium trance genre was a throwback: the 'trance-machine' Virus became 'obsolete' in the public opinion (which was an unfair impression). Later, the 'cheesy trance sound' originally appeared in Virus (and the synths mentioned at the top) has been re-created again and again (playing different rhythms and biased toward banging) just to use them in current EDM smash hits, usually played from Sylenth1, Nexus, often in heavily layered form.

So while the Virus turned up in nearly every studio, certainly just a few dared to explore its real potential beyond the preset tweaking, as the commercially available presets were excellent. The front panel of the Virus B and the redesigned, streamlined version in Virus C offered the most important synth functions at hand, but the rest of the functions were still available via the Edit button in the form of cryptic shortened text - it was not really inviting for deep discovery. For me the factual reference manual was decent yet a bit boring, but the Virus C-specific 'Programming Analogue Synths Tutorial' from Access helped me to dive much deeper.

Programming Analogue Synths - Virus Tutorial by Howard Scarr

This is a recommended reading for those who are already familiar with the cryptic Virus menu structure and terminology, but using any visual editor (like the Virus Sounddiver, Virus HC editor, TI Virus Control) or virtual version of Virus (Powercore or TDM) can dramatically help to locate functions in this complex instrument. After going through the examples you can consciously start from an Init preset and experience the infinitely exciting options of a Virus B / C.

Access Virus b


Over the years I used different Virus models, starting with the Virus B in 2001, I made my submission for the 2002 Access Music competition to re-mix the original Virus demo song (100% Virus B including the drums and percussion). I was just a preset tweaker for years, but recently I started to became interested in understanding the Virus much deeper. To become familiar with all parameters and their inter-dependencies took quite some time, but I think it was a well-spent period. As a result, I use Virus as a primary source for most of my music projects just to keep my hardly earned knowledge active :) 


Access Virus c


THAT Sound...

The cliche of 'modern virtual instruments dominate today's music production' is true to a certain extent: we have very fast CPUs, they are much easier to use in DAW environment compared to hardware, the sound is impressive, no aliasing, ZDF filters, etc. However good software instruments certainly benefit from this 'everything is better, faster' situation, unfortunately (...) the code resulting the sought after Virus sound was written and optimized for DSP chip for a long time, not for actual fast CPUs and supposedly it will stay like this, whatever the future brings for Virus. However the prolonged success of the Virus proves that the compound know-how (sound aesthetic, music, physics, electronics) and its implementation in software on a given hardware platform is much more significant than any theoretical CPU power or specification on paper. The DSP chips used in Virus are essentially obsolete now, but the software it runs still delivers the magic compared to other software synthesizers running on fast CPU but lacking pleasant character.

The typical sonic imprint of most software instruments (there are exceptions!) are restricted: they have more or less a kind of character, which you may like or not, or you may feel you reached the boundaries so it is not exciting anymore. Sure, these instruments still work as a tiny piece of a song, but we can not rely on this specific sound as a workhorse instrument. So you will not get celestial pads from a monophonic bass synth, as its focus is the bass. 

Virus is exceptional in this regard: its sonic range is very wide without the sound quality at stake. It can be anything from harsh, super fat, aggressive, dark, crushed and digital sounding up to a transparent, warm and fluffy, volatile tone. Sure it does aliasing occasionally in the higher registers, but its beauty is in its unpredictability (this is a key of the Virus sound) and organic, sometimes futuristic nature. It is able to spit out evil basslines with huge sub content or evolving ethereal textures by your choice.

What's more, the parameter ranges are somehow defined (or limited?) in a way that the sound has many ear-pleasing sweet spots, so it is quite easy to get sounds that matches the musical scope instantly.

Another striking feature compared to most of the virtual instruments is the depth and the strongly detailed, high-resolution sound. Just try the Noise or Wave FM Modes or modulate several parameters (e.g. the effect parameters) with the spectral wave LFOs - sounds become lively and still very musical. This high resolution sound probably calculated by the Virus software code internally which is converted then back to the normal sample-rate at the output, not sure how it works technically, but there must be something like this.

I think the main point of the Virus character is the sum of the quality components (osc, filter, effects, envelopes, etc), so let's see some of the special parts of the Virus that proves its holistic approach:

The 62 additional spectral waveforms dramatically expands the overall sound signature beyond the basic sine-triangle-saw-square quartet.  These are not just simple and regular waveforms with a few segments, but waves containing lots of peaks and trouts, all can be infinitely variable real-time. Here is a (quite boring, made just for reference) video about all these waveforms:



Watch just a single raw saw waveform played at C3 below - it has a smooth balanced roll-off on the higher region of the spectrum. And while it still does not say a lot about the qualities of the synths (all the others are pretty good sounding in comparison) most of the Virus components sounds subjectively 'smooth'. 

Saw oscillator C3 - Access Virus

Saw oscillator - VPS Avenger

Saw oscillator - Retrologue 2

Saw oscillator - Sylenth1

Saw oscillator - Waldorf Largo

Saw oscillator - NI Massive

Saw oscillator - u-he Zebra 2


Simple pseudo 2-operator FM Mode where Osc 1 wave is the modulator of the Osc 2 carrier signal. However, Osc 1 and Osc 2 are not real FM operators, as the genuine operators in other FM synthesizers are not just sound sources, but comes complete with unique envelopes, pitch and modulation data. What is unique here is the range of modulation signals: unipolar triangle (PosTri), bipolar triangle (Tri), any of the 64 spectral waveshape (Wave), Noise (with adjustable color) and even a realtime input signal! It goes beyond the original 'sine modulates sine' FM (as FM interaction works between Osc1 and 2 both set to any spectral waveshapes!) hence offering a broad range of superb FM sounds using just two oscillators.

In the classic oscillator mode, a Virus presets can use up to five sound sources: we have two full featured oscillator (Osc1 and Osc2), they interact each other through Sync, Ring and FM modulation. There is a third oscillator (Osc3) with slightly more limited features, plus a Noise source and finally a simple Sub Oscillator. Unison can go up to 16, so a single press of a key can bring out 5 osc x 16 unison x 1 voice = 80 oscillators. At this point we have reached the worst bottleneck of any Virus model: a preset using the 3rd oscillator, extensive unison and effects will considerably decrease the polyphony available and restricts the 16 part multi-timbral usage. It depends on the song arrangement and the presets used, but the maximum 5-6 multi-timbral playback is the real-world scenario before polyphony runs out and voice stealing occurs.

You can also blend

  • between saw and the spectral waveforms and
  • between saw and square wave

    to increase the number of available tone combinations ad infinitum in case of multiple oscillators.



    Adaptive Parameters Smoothing: this function buried deep inside the Common menu makes sound changes (e.g the modulations, pitch changes) a bit more sluggish, but you'll never ever hear any zipper sound from Virus when activated... switch it off and you'll hear a quite remarkable difference when tweaking e.g any Osc semitone manually or making a full low-pass filter sweep with higher resonance. While Adaptive Parameter Smoothing is an important 'smoothing factor' in Virus and was a great innovation at the release of Virus A, it is now a common feature in better software instruments. The main point is that you can disable it to get more gritty, old-style digital sound and to react to modulation changes faster.

    Oscillator detune affected by keyfollow is not linear - the higher up the keyboard you play, the less osc 2 and 3 is detuned internally which provides somewhat more musical results.

    The mature hardwired modulation routings of the LFO 1/2/3 sources with 19 fixed destinations and the Velocity source with 10 fixed destinations. I only miss here the direct Filter 1/2 control by Velocity, as we have to sacrifice mod matrix slots just to accomplish this basic expression helper.

    The huge amount of possible destinations – virtually every parameter of the synth, including all FX – not just in the modmatrix, but in the LFO section as well. There are only a very few parameters you can not modulate in this beast, but the downside is the limited number of modulation matrix destination slots in the B (6) and C models (9), which has finally been put in the TI right (18). Together with the aforementioned 29 hardwired modulations destinations the basically fixed architecture Virus unequivocally deserves the 'semi-modular' attribute...

    Randomness adds a significant fascination to sound in form of unpredictability and available in the Virus architecture at multiple points:

    1. all 64 non-periodic LFO 1 / 2 / 3 waveshapes (including the Sample&Hold and Sample&Glide) provides random variations for any parameter modulation
    2. you can select Random as a mod source in the modulation matrix, it works on a note-on basis
    3. arpeggiator playing order has a Random mode
    4. and finally the built-in and adjustable Random Patch Generator (has a dedicated button on the Virus C front panel) allows you to create fine variations of the actual preset - a great source of inspiration for making sounds you'd have never thought so...

    Well tuned envelopes with super fast snappy attack. According to the old Virus A catalog laying here, it takes 22 microseconds (!!!) from silence to full volume at the fastest settings. This attack is perfect for great plucks and meaty basses, despite the fact that its attack is fixed linear. But...with a little trick you can get exponential or logarithmic curves easily. The release phase is exponential and fades out very smoothly into silence without artifacts at its longest settings: around 47 seconds. The Sustain Time is also a Virus specialty: the usually steady sustain level can rise or fall over time.

    The three powerful LFOs with zoomable section, and with selectable mono / poly / one-shot modes. The number of possible LFO mutations due to the zooming / LFO shaping and mixing are staggering, giving you a source of unique and ever-changing cyclic and non-periodic modulators, see more details in the video Access Virus Oscillators above from 5:35

    The option to change and fix the starting phase of cycling elements:

    • Oscillators: By default, the Virus Osc are free running like in an analog synthesizer, but you can make them fixed too. Just use the Osc PhaseInit and set it to any value other than 0: set to 32 (top of the waveform) or 96 (bottom of the waveform) to start from its loudest point.
    • LFO: LFO 1/2 TrigPhase can be fixed or free running, at fixed state the LFO always starts from a defined point for any note-on.

    The Punch: it adds a tiny snap to the start of the attack phase, to emphasize the attack similarly like an enveloper shaper would do.

    The Analog Boost parameter adds some character - it actually very mildly bends the waveforms, transforming the sound more vintage-like - see its effect in the video above.

    All four (low-pass, high-pass, band-stop, band-pass) classic Virus filters are non-self-oscillating 2 and 4 pole filters, so it is possible to get 6 pole by cascading the two filters. The response of any single filters is very smooth, however they may become unstable when e.g. sweeping with the Filter 1 low-pass at higher resonance and filter distortion is switched on, while re-filtering it with Filter 2 at higher resonance - resonant bumps may cause unwanted clipping here and there, so a proper volume attenuation is required. Self-oscillating filters appeared in Virus C in forms of 1 / 2 / 3 / 4 pole ladder filters only in Filter1, and they can sound very rough and vintage. The nature of the classic low-pass filter somewhat invites users to make cool, dark sounds (like in Virus Dark Cinematics). Lighter patches requires a different approach.

    Virus Dark Cinematics Synthmorph

    The EQ per patch was a useful addition in Virus C with low-pass / high-pass and a parametric mid-range control. This mid Frequency, Q and Gain can be fully modulated from the matrix. The low-pass and high-pass distortion modes became redundant after the arrival of this new EQ but kept for compatibility reasons and this is one more chance for filter modulation anyway.

    A dozen of sophisticated distortion modes at two levels:

    1. post filter1 distortion on voice level and
    2. a global distortion effect affecting the final sound.

    Global distortion provides a very wide range of cool grungy sound especially when played polyphonically with the Digital, Rectifier and SampleRate Reducer plus mixed with voice-level distortion too.

    The really amazing effect section: These are not the usual grainy sounding effects found on some other synths from this era. The effects are the same first class as the rest of the components and stay very usable even at extreme parameters settings. Reverbs are very spacious and some special ones like Rev+Feedb1 and Rev+Feedb2 also contributes to the unique Virus sound. Delays are surprisingly versatile even with a few controls, the pattern delays instantly generate the dramatic grooves for any sound. The sound of the Phaser was a distinctive mark of the Virus from the early days, can sound very subtle vintage or strongly resonates for special effect. Chorus is a stereo widening and multiplication effect, quite essential as it helps you to get stereo widening without the need of switching Unison on. Believe me, it does matter when it halves or divides several times the polyphony available... In my experience all these effect parameters being modulated by envelopes, LFO, etc. are vital to add the 'out-of-this-world' label for the Virus.

    Despite of the popular misbelief, Virus can sound very analogue if you need that, just listen to the amazing Jarre-inspired analoguesque patches of Virus wizard Per Kristian Risvik (presets are downloadable on his website), all created on a single Virus kb (click the link to play) - it is all about programming experience:

    I Have a Virus... Now What?

      If you have an old Virus A / B / C somewhere in your room / studio, and you can afford to spend some valuable time to go through its parts together with the manual or any tutorial, always starting from the init preset, it is worth switching it on and start re-learning it! The more you can go into details the more you'll understand it so you can get much more out of it that's fits to your style. Even some small modifications of the Init patch often took me to a direction that gave me a unique and inspiring patch.

      Does it sound stupid to learn a synth up to the microscopic level? It depends... for me it required some time and persistent everyday work, but pays it off in the ability to be able 'thinking in sounds' and realizing it in Virus. In an upcoming article I'll show you some useful tips how to use the Virus a bit smarter.

      Using too many software instruments can easily feel you dizzy because of the multitude of choices. Moreover, the 'perfect quality without character' is often sounds compromised for the ear: it is clean, shiny, bright... but lacks personality. What if you could use just one synth, knowing it inside-out and be sure that it always delivers the character people are used to and like to hear? For me this could be the Virus above all.

      Viruses are probably the most complex and versatile digital synths on the market (excluding the workstation category, like Yamaha Montage), they are nasty creatures with incredible charisma. If you want to go deeper, the initial learning curve may be steeper, but if you are serious about synthesis and synthesizer sound design, any Virus model will always be a first-class and reliable choice on the long term.


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      • Dawnchaser on

        I’m def still Infected ;) In fact, I stumbled onto this article while hunting for some technical details on the DACs on the TI2, while designing a big epic pad for a trance tune I’m wrapping up

        This thing is so epic

        I wish Access would keep updating the lineage and giving us more polyphony and features – Virus synths are endlessly useful, and have a nice quick workflow

      • Barry Robinson on

        Great article ☺️ just spent all day taking apart and putting back together a Virus KC with a dodgy LED display, pots/buttons, and a broken keyboard. When I turned it on, saw that message and heard it working again I knew all the work was worth it ☺️ if you’ve got any tips for fixing dead keys it be incredibly grateful!

      • Carlo Demichelis on

        HI there,
        this article is absolutely fantastic.
        I liked it so much that i referenced and linked it to a video i did about Virus Powercore.

        Great work!

      • Phil Couling on

        Great article. I definitely feel inspired by it, to go back to the basics and rediscover my virus. I also really appreciated the links to Per Kristian Risvik’s work with the virus – great stuff, thanks! I look forward to future articles.

        TI2 Polar Darkstar

      • Robert Rossa on

        This is without doubt the best article on the Virus I have ever read. I switched mine on and went through stuff as I was reading.
        I have had it for a couple years and I always start from an init patch but still I learned plenty.
        I had seen the external audio as an FM source and never used it so I tried it with Bass Station 2.
        I had never actually turned the parameter smoothing off and at least with the TI you can pick various amounts of steppyness in addition to just turning it off. Really great stuff there.

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