Sonic LAB: Xils Lab PolyKB Software Polysynth

Monster French Polysynth Emulation      07/07/10

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    MP4 11:40 mins

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Welcome to the rarified world of the RSF PolyKobol - an extremely hard to find polyphonic synthesizer from the early 1980's. Only 30 were ever made, and they unfortunately were released at the same time as the DX-7 arrived on the scene, wiping out all contenders -  so its unlikely you'll have ever laid eyes, hands or ears on one.

XILS-Lab, with their tireless search for the perfect emulation, have clearly been able to track one down and decided that it was a synth worthy of emulation. They spent an inordinate amount of time getting the unusual oscillator waves right - using techniques such as BLIT (Band Limited Impulsion Train), they worked on ensuring the polyKB got the continuously variable oscillator waves right with no aliasing.

So How Did They Do?
The thing about these oscillators, is that they are continuously variable from TRIANGLE through SAW, SAW/SQUARE and SQUARE PULSE WIDTH. This means they sound quite unusual, and can be modulated all over the shop.

Good news though, they sound pretty darned sweet to my ears, with plenty of low end and lacking that buzzy quality that can be heard on some emulations, while still achieving highs.

While the PolyKB looks a little unfamilliar, it is in fact fairly straighforward in terms of architecture, with a few twists. Essentially, you have two VCOs (virtual of course) per voice, both offering low frequency modes for additional modulation, white or pink noise sources, a single 4-pole resonant VCF with drive, two multiwave, syncable (mixable) LFOs, 2 ADSR envelopes, a modulation matrix, arpeggiator, 128 -step polyphonic sequencer, dynamic panning and additional voice trigger based modulation. lastly, there are Chorus and Stereo Delay effects.

The PolyKB can be up to 16 voices, with several modes: Unison 2 to 6 voices which sounds massive btw, poly circular and reset modes, plus mono low, high and last not priorities.

CPU load is fair, but when you hear what it can do, you'll forgive it some extra CPU cycles.

Its All About The Sound
Now, I'm not a massive fan of software synths, I just generally don't find the interface to be worth the effort when it comes to programming, but I have to say the PolyKB is a totally different instrument to most. Simply, it sounds gorgeous - there's plenty of presets to be going on with but it is also eminently tweakable - once you get your head around the interface, which although is a little dark and moody, is not too tricky to navigate with perhaps the exception of the polyphonic sequencer.

Honestly, the raw waves with just a smidge of wave modulation sound great. The filter, which in software can so often be so dissapointing, whilst not a real screamer, is just very musical. the drive lending plenty of additional colour should you need it.

There's a wide range of sounds available, from luscious pads to deep basses and trancy leads with some really out there effects too. I was frankly impressed, and I really wasn't expecting to be for some reason. The effects while fairly limited, seem to compliment the patches well and kudos has to go to the chorus - with a couple of really tasty Solina style patches on offer.
Additionally, the voice pan feature can really bring any sound to life in the stereo field.

Firstly, the PolyKB only runs on either and iLok dongle or a eLicense, there's no other way, so people who arent fans of this method of protection will no doubt grumble, but I guess you gotta protect it some way and this is the way XILS have chosen. Secondly, it is only available in plug-in format - there is no stand-alone instrument for those who need it. 

Supported formats are:
        VST,AU, RTAS

There are a couple of issues I found, one being the polyphonic sequencer was a little tricky to use, but it can provide some excellent results with pererverence, there's no LFO rate indicator and sometimes its hard to figure out exactly what BPM division you are dialing in with LFOs or Clock - values are Tempo/128 - Tempo*8.0 which is not the most intuitive.
I also found an anomaly with the sync LFO button, it works per voice, and not across all voices, so a chord with mod will result in some fairly sea-sickness inducing modulation mess. Although I'm told this will be fixed in a forthcoming update.

I think this might be one of the first software synths I have actually fallen for. The classic analog sound with the rare French twist just appeals to my ear, and I found myself lost in sound for much of this review.

I know this might come across like some sycophantic love-fest, but this synth just makes me smile - its very musical. I  suggest you try this one out if you love the sound of a quirky classic polysynth. Wait, actually - I should discourage people - then it can be my very own secret weapon... Dont buy it - I want it all for me.

Priced at €149, $181 - available as a download from the website.
iLok or eLicense dongel required.


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