Review – PolyM by XILS-lab

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XILS-lab brings back a legend from the early days of synthesis – an expensive, hard-to-maintain synth from Moog is resurrected in software.


by Rob Mitchell, Sept. 2017


Back in the mid-1970s, a new Moog synthesizer was introduced to the world. They were already quite famous from the production of their mighty modular synth, and of course their highly acclaimed Minimoog. This time around, we got a polyphonic design. It first began as part of a larger project named Apollo that included two keyboards and Taurus pedals. Moog ended up producing the Taurus pedals as a separate product, and just one keyboard which they named the Polymoog.

Fast forward to 2017, and XILS-lab have now reproduced the Polymoog in software form. They call it PolyM, and it is a virtual recreation of that famous polyphonic synthesizer. Though you couldn’t save patches on the original hardware, there were eight presets you could choose from: Strings, Piano, Organ, Harpsichord, Funk, Clavi, Vibes, and Brass. Up to 71 notes could be generated using the TOS (Top Octave Divider) oscillators. It also had the famous Ladder filter, resonator filters, keyboard tracking, LFO modulation, EQ, and several envelope controls. That original hardware synth is great if you can find it, but is also expensive. A used Polymoog in good condition can cost you anywhere from around $4,000 to $8,000. Luckily this software is much less expensive, and of course you’ll be able to save as many patches as you’d like.


Getting Started

To install PolyM on a PC you’ll need XP (or higher), and it is available in VST, RTAS, and AAX formats.   For the Mac, you’ll need OS X 10.7 (or higher), and is available in VST, Audio Unit, and AAX formats. You’ll need at least one gigabyte of RAM, and a 2 GHz CPU. There is no standalone version. To install PolyM, you’ll need to choose between eLicenser, iLok, or iLok2. For this review I used iLok (authorized on my PC, i.e. no USB key), and there were no issues getting it all configured.

After you’ve loaded it in your DAW, you’ll see its main display. Across the top is the toolbar which lets you browse through the many presets that are included. If you are familiar with any of the other XILS-lab synth plugins, then you’ll be right at home with the menus for loading in presets. Basically how it works is that you can use the toolbar to load and save presets or banks. Using the button over at the far left, you can sort the presets by Bank, Author, Type, Project, Style, Feeling, or All. If you happened to have selected Author, the next column is where you can select which author you’d like.  After you’ve selected an author, then you can pick the style (for instance) and then you can see the list of presets that are in that style for the selected author. The A/B buttons allow you to work on a preset and then compare it to its original state.




You can choose between saw, pulse, or select both waveforms for the two oscillators. Each of these choices is selected with the push of a button in the Keyboard Waveshape section. The Lower and Upper labels refer to the two sections of the keyboard, and they depend upon where you place the split fader. It can be moved from the left to right along the length of the keyboard. The Lower section is whatever keys are to the left of the split, and everything to the right is the Upper. The Footage controls are the octave settings for each waveform. The oscillators can be free running or locked together using the two buttons on the right side of the Footage settings.

Above these settings are the Fine Tune/Beat and Master Gain Controls. The outer ring controls the fine tuning for both oscillators. The knob within the ring only lets you adjust the tuning of the oscillator with a sawtooth selected. This will change the “Beat” speed between the two oscillators. The Gain controls let you mix the levels of the different sections of the synth. The first one is for the overall level of PolyM, while the Direct slider is for the output of the audio without the three filter banks (more on these later). The last three sliders (MODE/RES/VCF) are devoted to changing the levels of those same three filter sections. The Octave Balance controls are for adjusting the levels (+/-12dB) of the notes played within octaves one through six.  Two octaves are grouped together on each of the three sliders. Rank Tune will tune the oscillators  (+/- 6 semitones) if they are set to the sawtooth waveform. The saw shape that’s below the Rank Tune slider is a quick reminder of its assignment.  At one point I had forgotten this and was wondering why it wasn’t tuning one of the oscillators, but then I noticed I had set it to a square wave.

To the right of the Rank Tune slider are the FM/PM controls. These are LFOs that are set to modulate the frequency of the oscillators. This function uses simple rate and amount sliders to control the modulation settings. If you use the Lock setting (instead of Free) with the square waveform on the second oscillator and the saw waveform on the other, it will then use Phase modulation. To the left of each Rate label there is a small button that will sync the rate to the DAW. The two buttons are a little small, and I almost missed them. Maybe if they were tad bit brighter it would be easier to notice them there.

Pulse width modulation (PWM) is possible in PolyM. It has separate Shape (pulse width) and Amount controls for the first two octaves (1-2) and the next 4 octaves (3-6). This section has its own LFO to modulate the pulse width, and its rate can easily be adjusted and synced to the DAW if you’d like. The “Rank Mix” can independently adjust the saw waveform level for the Lower and Upper sections of the keys. The “Loudness Contour” is the amplifier envelope for PolyM, and it has two modes available: ADSR and Legacy. If it is set to Legacy, you will have a DYN setting (how much the velocity will affect the envelope), Attack, Sustain, and Decay. If you select ADSR, a release stage is added to the end of the envelope with separate controls for the Upper and Lower sections of the keys. The Legacy envelope setting is an emulation of the way the original envelope generator worked in the hardware synth. Needless to say, envelopes are important in an accurate synth emulation. I won’t get into its details here, but it is explained at length in the manual if you’d like further information on how it works.



Now we get to the second row of controls which begins with a 24dB/octave zero-delay filter. This monophonic self-oscillating filter has Cutoff, Emphasis (resonance), and Keyboard follow controls. It also has a dedicated LFO you can use to modulate it with a sine wave and/or sample and hold output. The Amount slider adjusts the amount of the sine wave’s output, and the S&H slider is for the….you guessed it, the Sample and Hold output. You just have to make sure you get the levels for the VCF the way you want by using the Master Gain controls I touched on earlier. The next section to the right is for the Filter envelope, which has standard ADSR sliders and an amount control.

In the middle of this row of controls are the preset buttons with choices of Strings, Piano, Organ, Harpsichord, Funk, Clavi, Vibes, Brass and Vox. If you select the last “dot” button, PolyM will only use an internal filter setting for the particular type of preset you have chosen, and it won’t change all the other knobs and sliders which shape the nine preset sounds in various ways.

The next section is for the Polyphonic VCF and its envelope. It uses a 12dB/octave slope and it can be set to low-pass, high-pass, or band-pass modes. It has standard cutoff and emphasis (resonance) controls, amount, and keyboard follow sliders. If you just want to use this filter for the Upper or Lower part (or all) of the keyboard, that’s no problem because there are buttons you can use to change those settings. For instance, you can set it so the 24dB mono filter is on the Lower, and the 12dB poly filter is on the Upper. The ADSR envelope for this filter is located to the right of the Preset button section.

Now we get to one of my favorite parts of the synth, and that is the Resonators section. It uses three sets of controls that let you adjust the cutoff frequency, adjust the emphasis/resonance, and the amount of the filter.

There are three filter types to choose from: Low pass, Band pass, and High pass. They can be set to either 6 or 12dB/octave. In addition, this can be applied to the Upper, Lower, or the whole keyboard. When I was trying out this part of the synth plugin,  I used the MIDI learn function in PolyM (under the “Options” menu) to assign the nine sliders of my MIDI keyboard to the sliders in the three banks of controls. You are also able to modulate these Resonators (and many other settings) in the modulation matrix that is located in the Advanced settings panel.


Advanced Settings


The Advanced settings panel is where you can set up targets for modulation and adjust the effects that are included with PolyM. The first three slots for modulation can be used with Foot pedal/Aftertouch, Mod wheel, and Velocity.  Some of the destinations you can choose from include several filter settings, oscillator pitch and level, amp and filter envelope settings, square wave width, and many others. Six other sources/targets for available to set up some modulation. One feature I always like to have is the ability to modulate the effects, and as luck has it, PolyM has that capability built-in. That fact alone gives this synth plugin some well-deserved bonus points. The many targets are grouped into monophonic and polyphonic types.  Basically if you pick a monophonic source, you can modulate either a monophonic or polyphonic destination. If you pick a polyphonic source, then you can only select from the polyphonic destinations. The menus will automatically grey-out the ones you can’t select, so you don’t have to try and remember which is which.

The three effects available are reverb, delay and phaser. They can be switched on or off using the buttons in the lower-left. By the way, clicking the button just to the left of those effect buttons will turn on a waveform display. The reverb has a simple design with just pre-delay, reverb level, time and damping. It also has three different algorithms: Small, Medium, and Large. The phaser is the most elaborate of the three effects, with phaser level, speed, modulation amount, sweep (a frequency setting), stereo width, resonance, and a boost switch to give it some extra drive. The Delay effect is very basic, but it gets the job done. Its controls include delay level, time, left and right feedback, and it can be synced to the tempo of the host.



XILS-lab is known for reproducing many rare/vintage synths, and so it is no wonder they decided to take on a classic like the Polymoog. At the time I was writing this review, there were two display sizes to choose from, which is good, but I think there could be more. Hopefully by the time this review is published, PolyM will have a few more options in that department.  It would also be nice if the reverb had a few more controls, maybe some type of modulation and/or diffusion controls.

I did run into a few issues while using the beta version, but that’s what betas are for. The purpose of beta testing is to find out how it works in the hands of the end users, and see if they find any bugs along the way. Everything was smoothed out by XILS-lab, and they really do have an emulation of which they can be proud. If I could ask for certain extras to be added, I’d like more modulation slots, and the MIDI learn could be a bit easier to manage. Other than that, I really love this synth plugin. My congratulations go out to XILS-lab for doing such a great job of emulating a powerful and classic synthesizer.

PolyM was available at an intro price of $99 USD until Aug. 31, 2017.  After the intro was over, it was sold at its regular price of $149 USD. You can get more info about PolyM from the XILS-lab website here:






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