“Performance award and a 9/10 score…Pure music-making joy..some of the best modeled oscillators that software has to offer”

Simply, it sounds gorgeous…the first software synths I have actually fallen for.

PolyKB? YEAH!! Man, talk about a synth with LOADS of potential! EXCELLENT WORK! .

Such warmth and character that is lacking from so many other virtual synths…

Simply the most versatile and powerful analog modeled polyphonic synthesizer ever produced!

PolyKB III comes with PolyKB II included!
The PolyKB III captures the sound and spirit of the legendary RSF PolyKobol 2 polyphonic synthesizer, including its most revolutionary feature: Morphing analog Oscillators.
Morphing analog Oscillators sets PolyKB III apart from other analog synth emulations. You have instant access to hundreds of different analog modeled free running oscillators waveforms, far more than other synthesizers, including those that switch between oscillators sets. The icing on the cake is they can be dynamically modulated by a mulitude of sources.
In addition you get two gorgeous, creamy multi-mode filters, self-resonating in all modes, and Xils exclusive ‘0df’ technology. There are also three Analog modeled envelopes, with time multiplication, and great looping capabilities. Two complex LFOs are available with MIDI sync capabilities. All working to deliver a fat, warm and immediately inspiring analog sound.



3 Morphing Oscillators :

  • Oscillators are the only possible sound sources in an analog synthesizer. With 3 Oscillators, the PolyKB III now enters the exclusive territory of vintage analog synths like the Minimoog.

  • As the oscillators can morph continuously, and can also be controlled by all modulation sources rather than staying static (Triangle to Saw to Double Saw to Square to Pulse) you get endless possibilities.

  • A double Hard Sync algorithm is on board (osc2/1 AND osc3/2). Finally, A 4th noise oscillator is there too, and oscillator 2 & 3 can also behave like LFOs… @ audio rate, of course.

2 Multimode Filters :

  • There are two 0df Self Oscillating capable filters, with pre-post drive modules, direct Keyboard tracking, each with their own dedicated envelope for immediate tweaking. Multiple hardwired modulations. And multiple possible custom modulations as well: Total control!

  • Each oscillator can feed Filter 1, or 2, or both. Filters can be cascaded (1 -> 2). And you can perform filter morphing with any modulation source by controlling the filter 1/2 balance.

  • The filter is an essential part of each analog synth, but you’ll have to try the demo to get the feel of these, as nothing we can say could fully describe its creamy and precise character.


  • Only 30 PolyKobol 2 were ever built.

  • RSF synthesizers were well regarded by renowned artists such as Depeche Mode, Jean-Michel Jarre, Hans Zimmer, Peter Gabriel, Vince Clark and Vangelis.


  • 3 Morphing oscillators
  • 2 Creamy Multimode 0df Filters
  • 3 Envelopes, 2 LFOS
  • Polysequencer, arpeggiator, vintage effects
  • Unmatched analog presence and feeling
  • Tomorrow’s technology: Hundreds of modulation possibilities, including 2 Unique modulators Per voice, a supersized step sequencer and two Mod Matrixes
  • Three aliasing-free morphing oscillators: from triangle to pulse, through saw.
  • Two 4 poles Multimode self-oscillating filters
  • Three Loopable envelope generators (ADSR)
  • Two MIDI syncable LFOs
  • One MIDI syncable Sample and Hold
  • One 128 steps polyphonic sequencer/Trance Gate Sequencer/Phrase Player
  • One Per voice VoiceXY modulator
  • One Per voice SpaceXY Spatializer
  • One Hardwired Macro Modulation Matrix
  • One User Macro Modulation Matrix
  • One Arpeggiator (monophonic and polyphonic)
  • Four Vintage effects
  • Six Mono/Unison/Poly playing modes with up to 16 voices of polyphony
  • All parameters are MIDI controllable


  • Mac OSX 10.9 and later (64bits only): VST, Audio Unit, AAX (native), Apple M1 with Rosetta2
  • Windows 7,8,10 and 11 (32 & 64 bits); VST, AAX (native)


The limited features demo keeps a pure sound ! no crackles, noise or silence ….
  • No preset or project saving.
  • No bank import or export.
  • No automation or MIDI cc
  • Unlimited time
  • License Free : No dongle, license or serial number required

A Modulator for Each Voice !

It wouldn’t be a XILS-lab instrument if it didn’t have innovative and exclusive features like each voice having its own modulation engine, or a giant Step Modulator, to propel it into the 21st century.

You can make each note sound different : The Voice XY module is a single Note Quad XY modifier playground. You have total control over the creation of subtle or wild variations for each note in a 2D square with 4 different parameters.

Custom Per Voice modulation, The Voice XY Pad Modulator:

Per Voice modulation means that each new note played will be affected by this modulator, and will sound different from the previous, and the following ones. The voices are represented, on screen, by red balls that you can move around within a square field. The vertical and horizontal position of each ball can modulate two different parameters, each with a dedicated amount knob, which allows you to choose from a plethora of targets.
With this tool, you can perform an infinite number of sound shaping tasks, like tailoring your own analog drift, especially suited to the track you make, or make crazy ever-changing sounds.
New in version 3.5, the Path Function: Draw a path for each voice, to each note for it’s own unique journey.

Create your own 3D Space :

With the Space XY module, you can place each note in a three dimensional space, and build stereo-scapes that no other effect can achieve. On top of that, you can make it move with the inbuilt chaotic functions, adding incredible life to your sounds. You have never had so much artistic control over the stereo field.

If you combine these two Single Note modifiers with the True Unison engine, you’ll soon get amazing, dense, and breath-taking sounds, that will proudly take their place in a mix immediately. Operating it is easy, you simply place and move control points of the voices, in the square. Very simple, immediate and powerful !

Hyper Modulations : The Polysequencer can now be used as a 128 steps, 4 lines/16 destinations giant Step Sequencer Modulator, allowing you to sculpt not only the most detailed TranceGate patterns, but also Slides or incredible rhythmic patterns. Or modular anything with anything you want, you choose.

Everything is here to allow you to create fully organic and expressive presets. PolyKB III is the ultimate blending of analog authenticity and powerful modern technology.

Polyphonic Sequencer: Vintage or futurist Sequences & Phrases

The 8 part Polysequencer takes the concept of step sequencers one step beyond. You can record 8 parts in real time, or in step mode.
You can transpose sequences according to the root note with the tuned mode. It also has an incredible step play mode that you can use for live chord sequences.
Several different play modes allow you to use it as a Phrase that you can trigger on the fly, or as fully controlled tracks with the Midi CC automation of the start/stop functions recorded in your DAW.

You can zoom in/out of the GRID, record velocities.
Full editing capabilities of notes/parts: muting, editing, etc.
Once all this is done you can save your sequence in its own format and begin to build your own library of custom sequences.
And you can even use it as a source modulation in the mod matrix to make superior sequences… (See above to use the Sequencer to send automation data only)

Supersized Step Modulator Sequencer:

4×128 steps of pure pleasure!

You can use the PolyKB III sequencer as a giant Modulation-only Step Sequencer, and write up to 4 different step sequences, up to 128 steps long.
Each sequencer line can control, via the User Matrix, up to 4 different synthesis parameters, including both filters, oscillators, and also envelope segments, or LFO output Levels.
Everything becomes possible, from the most detailed Trance Gate patterns, to incredible groove parts!

True Unison (& Stereo Scene)

  • The PolyKB’s gorgeous analog character can be reinforced by different features, like the custom number of Unison voices, and our very special Drift knob (Which randomly adds a, more or less, drastic and distinct character to each voice).
  • In Addition, our exclusive DynaMYX Pad (Dynamic Stereo Modulation XY Pad) allows you to build unique stereo scenes by allowing each note played to have a distinct stereo position. Controlled by polyphony, this unique effect will make your analog the widest, most intense sound you have ever heard. We have provided you some great presets to start with and we can’t wait to hear what you come up with.
  • Of course you can also control the width of the overall stereo scene, and the direction of the mics. 

Analog Modeled Effects

  • Delay, Chorus, Phaser, Reverb, EQ: The PolyKB III is equipped with vintage Chorus and Phaser units, and an analog type Delay & Dual EQ.

  • Delay time, Chorus & Phaser rate can be used as targets in the User Mod Matrix to build Solina style Ensemble processing, or other strange effects.  

  • These effects are simple, but have a strong character, and sound unique. And, if you use them, it’s just impossible to replace them with any other external effects.

Total Control:

  • You can assign any Midi CC to any synthesis parameter to fine tune some midi parts, or achieve the most precise automations. When combined with the Polyphonic Integrated Sequencer you can build anything from ever-changing patterns to solid bulletproof analog sequences reminiscent of older times.

  • You’ll also get some additional parameters that make full sense when playing music, like the possibility of controlling the speed of all Attack parameters with velocity (Found in the Hardwired Matrix Modulation), or the Decay/Release of all envelopes. This is the key to expressive Keys or Brass/Strings patches, but you can use this to design outrageous expressive leads as well.

  • Additional parameters related to the envelopes are the 3 different Mono Modes, with low, high or last note priority. The Poly Circular and Poly Reset play modes are tied to the Voice XY and Space XY pads described above.

Hardwired macro modulation: The Matrix

  • Hardwired modulations allow you to change the sound in a dynamic way by just establishing a connection (click on a switch) between different modules, then using the amount knobs.

  • The PolyKb III offers you more than 35 hardwired modulations, with various sources like LFOs, Envelopes, and also oscillators or noise to perform AM & RM, or Filter FM. Not counting the VCA & VCF Envelope amounts, or KB Tracking amounts, which are also hardwired modulations

Custom macro modulation: The User Matrix

With custom modulations you can freely choose the sources, targets and amounts of the modulations.

  • The PolyKB III offers 4 custom macro modulator matrixes. Each of the 4 sources can simultaneously control up to 4 parameters, so 16 additional freely assignable modulations are possible. Amounts can be positive, or negative.

  • You can choose from a plethora of sources, and dozens of destinations, including filter balance for morphing between filters, envelope segments or output levels, LFO output levels, etc. The road to creativity is, once again, fully opened for all kinds of creative uses!