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Dave Smith Poly Evolver Keyboard

Four-voice Analogue & Digital Synth
Published March 2006
By Steve Howell

Dave Smith PolyEvolver KeyboardPhoto: Mark Ewing

The Evolver began as a mono desktop unit, then became polyphonic, and now there's a polyphonic keyboard version. It's almost as if Dave Smith's latest synth is steadily evolving back into his earlier Prophet 5... We check it out.

As has been explained in these pages before, Dave Smith's resumé is quite a read. A major innovator in the hi-tech music world since the mid-'70s, he designed the first truly programmable synth, Sequential Circuits' Prophet 5, as well as the monophonic Pro 1, Prophet 10, the gorgeous T8, and many others. He is credited as one of the fathers of MIDI, having helped to design and promote this now-ubiquitous interface. He was also the creator of Vector synthesis in the Prophet VS (later to blossom into the Korg Wavestation) and was developer of the world's first proper software synth, Seer Systems' Reality. Having just one of those achievements on my CV would make me very happy!

Evolving Evolvers

But despite having developed software synths, Dave is today back to making hardware products in the form of his Evolver range. First off the line was the Evolver, a monophonic synth in tabletop form reviewed in SOS February 2003. This was followed by the Poly Evolver rack (see SOS December '04). The Evolver uses a 'matrix' method of programming, where you select a line of parameters to edit on the matrix with the buttons at the side and then adjust that line's parameters with the eight encoders at the top of the matrix — it's a capable, but fiddly interface. The Poly Evolver (arguably) took a backwards step with a 16x2 LCD and an 'up/down' page system (though you can use a mono Evolver to program it, or a PC/Mac software editor). That's the Evolver story so far, but now everything has changed with the arrival of the Poly Evolver Keyboard (or PEK), which seeks to combine the best of both previous versions and improve on them, being polyphonic, fitted with a keyboard, and, as you can see above, covered in many more controls than graced the front panel of the original Evolver. There are rotary encoders, illuminated switches and blue LEDs — it really is a classy thing to look at. There are even wooden end cheeks, and although I know they make no contribution to the sonic quality of the instrument, they do add something to the 'experience' of owning and playing it.

The PEK's lightweight velocity- and aftertouch-sensitive keyboard might not be to everyone's taste, but it's perfectly adequate for the synth sounds on offer. The PEK also sports two transparent wheels to the left of the keyboard, which glow a beautiful blue; in subdued lighting, the PEK is a thing of beauty (see the final page of this article). Even my wife, who is usually quite unimpressed with the various bits of gear that pass through our doors, was very taken with the PEK's cosmetic design, calling it 'the ultimate big boy's toy'! And she was absolutely right...


I won't spend too much time on the synthesis functions available to you (although I may allude to them by way of my description of the panel) as these have been ably described in Paul Nagle's previous reviews of the Evolver and Poly Evolver, but to summarise, Dave Smith's products are a potent marriage of digital and true analogue technologies in one instrument. Each voice has two digital 'vector' oscillators and two analogue oscillators per voice which are fed to an analogue low-pass filter (the digital oscillators by way of a digital-to-analogue converter) and an analogue voltage-controlled amplifier. From here, the signal comes back through an A-D converter to be further integrated with the digital audio processors.

Around the back, all seems complex, but it's all quite logical. Each PEK voice gets its own stereo output, so in addition to the headphone jack and main stereo outs, there are a further eight jacks (two per individual voice), plus a stereo pair for the audio inputs, then the power connector, connectors for sustain pedal and two continuous footswitches, the de rigeur MIDI trio (plus an extra connector for daisy-chaining other Evolvers and Poly Evolvers), and finally, those completely gratuitous (but very impressive-looking) blue LEDs!Around the back, all seems complex, but it's all quite logical. Each PEK voice gets its own stereo output, so in addition to the headphone jack and main stereo outs, there are a further eight jacks (two per individual voice), plus a stereo pair for the audio inputs, then the power connector, connectors for sustain pedal and two continuous footswitches, the de rigeur MIDI trio (plus an extra connector for daisy-chaining other Evolvers and Poly Evolvers), and finally, those completely gratuitous (but very impressive-looking) blue LEDs!Photo: Mark EwingThis means that you have the best of both worlds: software LFOs and envelopes, four step sequencers, effects, sophisticated modulation control, precise control of parameters, and loads of memories to store sounds thanks to the digital side of the synth, plus the warmth and character of analogue. The PEK's voice structure is unchanged from that of the other Evolvers, so for more details, head for those older SOS reviews.

What sets the Poly Evolver Keyboard apart is that panel — a knob or switch for (almost) all the functions makes this powerful synth considerably easier to use than the other Evolvers, and most of the everyday functions are typically just a knob or switch away with other, less commonly used functions being available on menus shown on the 2x16 LCD (but even those use encoders to select or set their values).

The panel is very well laid out. The main business area (oscillators, filter, envelopes, effects and output parameters) is right in front of you, directly above the keyboard and follows a logical progression from left to right. Furthermore, good labelling makes it perfectly clear how the signal flows through the instrument, especially with regard to showing the various feedback paths that occur in each voice.

Other functions, such as Envelope 3 and the four LFOs, are found at the top left of the panel and the four step sequencers are to be found at the top right. Dominating the centre of the panel is the programming area, where the 512 sounds (four banks of 128 sounds each) can be selected using the plus or minus buttons, two data encoders or the large keypad. The instrument's three different modes of operation (Combo, Program and Global) are also selected here (see the box overleaf for more on this).

At the rear, the PEK sports a multitude of audio outputs. There is a headphone output, a pair of main stereo outputs which carry a mix of all the voices, and there are also individual (stereo) outputs for each of the voices. Inserting a cable into these (balanced) quarter-inch jacks removes that signal from the main stereo outputs, as it should in my opinion. There is also a stereo audio input allowing external signals to be processed through the PEKs filters and effects. Naturally, it has MIDI, plus a 'special' MIDI/DIN connector for daisy-chaining other Evolvers to expand polyphony. As the PEK is more biased towards performance than its counterparts, there are two variable pedal inputs (assignable) and a sustain pedal input.

Disappointingly, power is supplied by an external PSU — on a keyboard of this nature (and price), I was expecting a sturdy mains cable and built-in power supply. In fairness, it's not a wall-wart type — the PSU is connected to the mains with a cable of a decent length — but it was still a surprise when I removed the PEK from its packaging. Disappointing as well was the omission of a digital audio output, which I would have thought would make the PEK more flexible in a modern studio.

The final item on the rear panel is another for the 'eye-candy' department: four bright blue LEDs that pulsate according to the rates of the four LFOs. These must have been included for visual purposes, because they serve no practical purpose whatsoever otherwise — but they do look very nice! I guess it's only a matter of time before synth nerds in the audience will be guessing which patch is being used based on the respective rates of those LEDs...

King Of The Mode

The PEK has three main operating modes: Program, Combo and Global. Global is the most utilitarian of these, dealing (as it usually does) with overall tuning, MIDI settings, sequencer clock, external audio input gain, LCD contrast and the like.

Of the other two options, Program mode is the simplest: you play or sequence a single four-voice sound, and have 512 sounds to choose from. You can also stack all four voices in a Unison mode for truly dangerous sounds, and there are various playback-triggering modes.

Combo mode combines several Programs to provide simple four-part multitimbrality. Many of the pre-programmed Combo memories are complete musical pieces in themselves that utilise the four sequencers playing each part separately. Others stack Programs or create keyboard splits. Some are keyboard-triggered sequences with separate Parts running in different octaves, at different clock divisions and at different sequence lengths. Others are 'free-running' quadra-timbral sequences over which there is no control other than by moving the front-panel knobs relating to the currently selected part — transposition of these from the keyboard is not possible, which is a shame. It's also worth pointing out the four-voice limitation here — each of the four parts is, of course, strictly monophonic.

Combo mode is by far the most entertaining, as it can be used to realise complete compositions. However, the limited voicing means that such arrangements must be limited to four parts. That said, the presets show off what's possible and are quite inspirational (over-use of distortion notwithstanding), ranging from the 'innocence' of early multitracked synth work in the style of Tangerine Dream and Kraftwerk to examples which owe more to four-on-the-floor techno. There is no denying that the Combo mode throws up many interesting musical ideas that might not be apparent when working with a more conventional multitrack sequencer.

Control Centre

At first glance, the PEK's control panel looks pretty straightforward (and indeed, for the most part, it is) but I was surprised to find continuous encoders for all the controls. I am in two minds about the use of these in this context. Of course, they allow a control movement to take immediate effect from the parameter's stored value, but as you are adjusting them, you have no idea when you are reaching the control's 'end stops' (so to speak) and I found myself referring to the LCD (which, like Novation's K-Station, shows the value of the selected parameter's value) far too often for such a knobby synth.

Furthermore, some of the parameters have quite a large range, and so some of the encoders require a few turns to cover that range. The Filter Cutoff control, for example, requires a few turns to create a full manual filter sweep, and the Resonance, LFO Rate, and Filter Env Amount controls, as well as others, seem to require more turns than we're perhaps used to.

It'll look great on stage... the PEK in reduced lighting conditions.It'll look great on stage... the PEK in reduced lighting conditions.Photo: Mark EwingIn defence of this method, however, apart from immediate 'take-up' of a parameter's stored setting, it also allows a finer degree of accuracy when setting values, and that has to be applauded. I guess it just takes a bit of getting used to after using conventional 'pots' with physical end-stops at seven and five o'clock. It would have been good, perhaps, if the encoders were 'velocity sensitive' — in other words, if quick movements allow coarse settings whilst slower movement allow more precise settings. Also curious is that the encoders caps have pointers, which are largely meaningless on totally continous controls. On a more positive note, 'zipper noise' (ie. stepped digitised value changes) from the controls was minimal to the point of being inaudible.

Reservations about the encoders aside (which might well not bother anyone else — it's something of a personal gripe), there is generally a dedicated control or switch for each function, which is great. There are a few compromises — there's only one set of controls for the the four oscillators, the LFOs and the step sequencers, for example — but illuminated switches allow you to select the 'module' you want to tweak very easily. But these compromises are understandable, as it would be unfeasible to provide dedicated controls for all of these.

In most other respects, this is very much a 'no-compromise' design — Dave Smith could easily have tucked a few of the dedicated functions away on a menu-based programming system, and the PEK could probably survive without some of the 'eye-candy' like, for example, the master octave LED indicators, the pulsating blue LEDs for each of the four LFOs (especially those duplicated on the rear panel!), and the large dedicated program number display. The PEK could also have shared common controls for the three envelopes, and instead of having dedicated switches to select oscillators, LFOs and sequence banks, it could have used one (frustrating) button to cycle through each of those. But Mr Smith has obviously put function and usability before form (and issues of cost) to create a knobby user interface that is simple but comprehensive and puts most functions right in front of you. I am not denying that there are few areas (notably modulation) where you have to figure things out (and here, a larger LCD might have have helped) but overall, this is generally a gratifying synth to use despite the programming depth and complexity available to you.

Software Vs Hardware — The Long View

Sometimes it feels as if software synths are gradually displacing their hardware forerunners, and might one day cause them to disappear from studios altogether. However, there are still many people who prefer hardware, and it would seem that Dave Smith is one of them. Despite having developed the world's first software synth (Seer Systems' Reality), he has reservations about software instruments.

Interestingly, his objection is not so much one of sound quality, but more to do with the long-term 'value' of software. As he told Mac Music in an interview in 2003, although there's a multitude of software synths available today, with seemingly every college student having designed one, he believes that software synths are a bad business model, requiring constant (and therefore costly) updates and testing under different operating systems with different hosts to ensure that they continue working: "a constantly moving target", as he called them. As a result, his belief is that the majority of these swiftly designed software instruments won't still be working in 10 years' time, because the sheer amount of work required to keep them up to date will weed out all but the most successful of them. This is apparently why he prefers to design hardware products — because he feels that they are intrinsically more reliable and will still be of value in the decades to come.

Whether or not that's true, it certainly holds for the reliability of his PEK — I had not a single problem during the review period. And such is the depth of the PEK's programming potential, I feel certain that this synth will still be a source of musical inspiration 10 years from now.

Sounding Off

How does it sound? Fabulous for the most part! I am a bit at odds with some of the presets, many of which attempt to sound 'modern' simply by slapping on distortion rather too often for my liking, but this is easily rectified by, well, turning down the Distortion knob. Many of the presets show off the instrument's broad capabilities, from genuine (not modelled) analogue warmth through to biting digital textures. The unique Feedback section, in particular, takes you into territory not normally found on other synths and the panel legending shows clearly how this interacts with the sound. I am also especially pleased to see that Dave Smith has not 'compromised' the digital oscillators by refining them to remove aliasing, and even the manual proudly proclaims that like the Prophet VS, they sound 'quite trashy at higher frequencies', a 'feature' which only serves to add more character to sounds.

Such is the depth of the PEK's synthesis capabilities that many of the presets explore territories inaccessible to other synths, notably long and (yes...) evolving sci-fi textures that could have come straight off the soundtrack for Forbidden Planet or from the depths of the BBC's Radiophonic Workshop in the late '60s and early '70s, when they had just taken delivery of their EMS VCS3s and AKSs. Many presets reward you with abstract, atmospheric soundscapes that slowly develop over time. At the other extreme, however, the PEK is equally capable of underpinning a track with strong basses and lush pads, or dominating it with strident lead lines, spikey arpeggio textures and more.

In short, this is a powerful, capable synth that has a place in almost any genre of music, and with a distinctive character that sets it apart from other synths on the market. There's only one criticism really; in this day and age, it's hard to overlook the fact that it is four-voice polyphonic, a spec last seen on keyboards in the days before Dave Smith had even designed the Prophet 5. There's no way to increase this polyphony with, say, voice expansion cards, although you can daisy-chain multiple Poly Evolvers to achieve this.

Whether this is an issue for you is up to you to decide. Personally, I found it to be a restriction, limiting even the use of an octave bass and a simple triad (a total of five notes) for pads and the like, and more ambitious endeavours are out of the question without note stealing becoming obvious. I would have loved eight voices to play with, but I suppose this would have added yet more to this product's already fairly substantial price.

But to whinge about polyphony is, to some extent, to miss the overall point of the PEK, in much the same way that it is churlish to complain that the Minimoog Voyager is monophonic. The PEK is a well-built and classy-looking instrument which is equally at home in the studio or on stage. The hands-on, knobby control panel makes programming it much more manageable than the company's other Evolvers but (thankfully) there is still that beguiling element of serendipity, whereby a twist of a control can yield an unexpected result. If you like hardware and you like keyboards, check out the PEK — it's a deep, unique-sounding synth with vast sonic potential. I think you could explore it for years to come and still not exhaust its store of surprises. 

Published March 2006

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