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Dave Smith Evolver

Hybrid Analogue/Digital Monophonic Synthesizer By Paul Nagle
Published February 2003

Dave Smith, creator of the Prophet 5 and Wavestation, moved into software synthesis in the '90s, but now he's back with what he calls 'the ultimate dongle' — a hardware analogue and digital synth. We find out if he's still evolving...

Dave Smith Evolver.Photo: Mike CameronIt's no exaggeration to say that Dave Smith is one of the founders of music technology as we know it today. Not only did he create the world's first commercial polyphonic, programmable synthesizer (the Prophet 5), but he was a key player in the development of the MIDI protocol, as well as co-author of the first commercial software synthesizer to run on the PC, Seer Systems' Reality (see SOS November 1997).

More recently, Dave helped out on Roger Linn's Adrenalinn, and this sparked an interest in making a new instrument of his own. Thus, the Evolver is Dave's first solo project in years, born out of a desire to build a piece of real hardware again — a concept Dave neatly describes as "the ultimate dongle".

I first became aware of the Evolver whilst net surfing, and, after downloading the manual, checking out the price and listening to a few early audio demos, my curiosity was piqued. It was partly Dave Smith's reputation which attracted me, but it wasn't just that — the Evolver also seemed to offer considerable bang for the buck. For here is a monosynth with four oscillators (two analogue, two digital), twin analogue low-pass filters, a built-in step sequencer, stereo audio inputs, delay and distortion effects, four LFOs, three envelopes and modulations galore — all for $500, or about £330!

Black Box

Dave Smith EvolverThe Evolver is a black metal desktop box, occupying just 27 x 15 x 4cm. If you tend to judge synths by their knob count or ability to kickstart a hernia collection, you might completely overlook it. Given its background, it's no surprise that there's a resemblance to the Adrenalinn (see SOS September 2002). Indeed, the Evolver uses the same matrix-style interface, where you select a line of parameters to edit on the matrix with the buttons at the side, and then adjust individual parameters with the knobs at the top. There's also a three-character LED. The drawbacks of such displays have been well discussed in these pages before, and the Evolver is no better or worse in this respect than others we've seen. After a little while, you start to remember the most common parameter abbreviations; I found it took me about a fortnight before I no longer needed the manual at all.

Dave Smith Instruments Evolver
  • Analogue and digital hybrid
  • Built-in step sequencer
  • Stereo inputs and extensive sound-mangling options
  • The price (despite the UK Customs duty on top).
  • Matrix style of programming
  • No headphone socket
  • Oft-inscrutable three-character display
At just 500 US dollars, the Evolution is a minor marvel, packed with features that could keep you delving for years. Its sound isn't revolutionary, but it's a solid piece of hardware that you can gig with, use to process external signals, or just to generate wild sequencer patterns. Hard to resist.


All the functions of the synth are printed on a blue Lexan overlay — essentially an eight-by-eight grid with the parameter names shown in small white text with an alternative set underneath them in yellow. The latter set are the 'shifted' options and effectively double the number of parameters available. Shift is enabled temporarily by holding down the key of the same name, but if you quickly 'double-click' it, it remains active until you push it once more to return to normal operation. A small red LED at the start of the selected row flashes if Shift is active.

A further set of 16 parameters of a more global nature are located outside the matrix above the row of knobs and are accessed by the 'Main' button. The knobs themselves are of the continuous type with subtle notches to facilitate fine parameter adjustment. As you start to make edits, you discover that carefully turning the knob by just a single notch doesn't update the parameter, it simply displays its current value, which is helpful if you want to see the previous setting before tweaking.

The innocently labelled 'Sequencer' button transforms all the knobs and matrix rows into a four-row-by-16-step sequencer; you can toggle between synth and sequencer operation at any time by pushing the button. Dedicated transport buttons, positioned under the display, control sequencer Start/Stop and Reset. When running, the eight LEDs below each knob light in turn to mark progress through the sequence.

The rear panel sports the usual three MIDI sockets plus left and right signal inputs and outputs. Power is supplied by a rather snazzy universal adaptor that arrives complete with several optional AC prongs: it's ideal whether you live in mainland Europe, the US or the UK. Once you slide the appropriate prongs into the groove on the adaptor, the Evolver is ready to go. Sadly there's no headphone socket, but the Evolver's outputs are intended to drive most headphones — providing you rig up a suitable adaptor lead.

Following a suggestion in the manual, the first thing I did (after connecting up) was hit the Start button. The sequencer kicked into life, spewing out the raw, evolving patterns that inspired the synth'sname. I auditioned a few more sequences to get a feel for the range of sounds on offer, and found many of the factory patches to be grungy, distorted or downright intimidating. Happily, some of them did hint at subtler possibilities, and brought forth intricate, looping melodies from within. You can find out more about the sequencer in the box elsewhere in this article — but first, let's see what makes the Evolver tick.

Four Play

One of this synth's most attractive features is its oscillator configuration: two analogue and two digital types. All four have a massive 10-octave range and can be used simultaneously, although you need to be careful not to introduce unwanted distortion by over-boosting their levels. Each oscillator has an individual glide amount, although curiously, the synth does not have an overall glide setting, nor does it respond to the designated MIDI controllers for glide/portamento.

Oscillators 1 and 2 are analogue and are routed internally to the left and right channels respectively. Sawtooth, triangle and variable pulse waves can be selected, plus a waveform that is a sawtooth/triangle mix. Oscillator 1 may also be hard-sync'ed to Oscillator 2.

Despite sounding very fat and warm, these oscillators are also impressively stable. Should you wish to emulate older, less precisely tuned analogues, a so-called 'oscillator slop' parameter is provided. This is OK, but rather subtle — to get more 'sloppy', you could always vary the pitch with a small amount of LFO modulation (with a random waveform) instead.

Oscillators 3 and 4, by contrast, are digital, although like their analogue counterparts, they are hardwired to the left and right internal busses. Their 128 12-bit waveforms include waves 32-125 from the Prophet VS as well as an area for loading user waveforms. As shipped, the user locations (96-128) duplicate factory waves 1-31. There's currently no program available for uploading your own waves, but I expect somebody will develop one before too long. The 12-bit resolution of the ROM waves reflects the state of affairs on the original Prophet VS, but interestingly, the user waves may be up to 16-bit resolution. The preset waves exhibit all the characteristics that made the VS such fun. Expect aliasing, strange artifacts and weird noises — especially at higher frequencies. Each digital oscillator is capable of frequency-modulating or ring-modulating the other; you can even do both simultaneously if you're feeling brave enough to handle the (often) raucous result.

The combination of digital waveforms and a sequencer offers an unmissable opportunity to step through them automatically, for powerful wave-sequencing effects. To this end, wave 95 has been purposely left 'blank', making it easier to insert spaces into a sequence and funk it up. This is exactly the kind of thing you'd hope for from the man whose team brought us the Korg Wavestation, and my only disappointment was that this sequencing method was the only way to externally control waveform selection. The digital waves are not available as modulation destinations, meaning you can't select them via an LFO, velocity, or key position (for example). As future OS upgrades will be available as simple MIDI files, my fingers are crossed that this will appear in some form or other at a later date.

Evolutionary Process

A handy signal diagram in the manual (shown below) explains the internal routing far better than it's possible to do in words, showing the paths of the oscillators through filters, delay lines, distortion blocks, and so on. The twin stereo inputs are a great bonus on a synth this size, opening up all its processing power to external sources. Thus, the left external signal travels through the same filters, feedback circuits, and so on as Oscillator 1 and 3, while the right signal takes the path of Oscillators 2 and 4. Input level is set using the Input Gain control in combination with a Clip LED. An Envelope Follower signal and Input Peak level are derived from the left audio input, and may be used as modulation sources to be routed to the usual wide range of destinations.

I've looked at using the filters for sound processing elsewhere in this review, but the built-in delays are also significant contributors to the Evolver's overall character. Essentially there are two — a tuned 'feedback' delay line and a multi-tap delay. The former is actually twin identically-tuned delay lines (one for each channel) with the main feedback loop quantised into semitones over a range of C0 to C4. You can therefore 'play' the feedback frequency by modulating it from the sequencer (or other sources) for some decidedly unusual metallic sounds. The Grunge parameter gets quite nasty at high feedback levels, and I'm sure somebody with attitude and pointy bits of metal in their face will put it into regular use. I'm showing my age here, aren't I?

The delay line has three independent taps, each with a variable level and time. Two feedback paths are provided — the first simply feeds back into the delay input for repeat delays, tuned feedback and the like, but the second sends the signal back to the input of the analogue filter, allowing even more drastic effects. Delay time can be a maximum of one second and, subject to both this and current tempo, the delay can be synchronised with the sequencer in divisions ranging from a 16th step to 32 steps. The delay line is a simple mono affair with the output of all delays summed and sent to both outputs.

Distortion is obtainable from the Evolver in many forms, whether from overloading the input signal levels to the aforementioned Grunge, plus the so-called 'Output Hack' and Distortion parameters. When processing an external signal, the 'Input Hack' parameter can, if used excessively, pretty much destroy the sweetest audio before it even reaches the analogue filters, high-pass filters, or distortion algorithm. I understand that the Evolver was almost simply called Noise, presumably due to its eagerness to make lots of it!

The final output signal may be panned hard left and right or dead centre, with a few in-between and inverse settings too.


The Evolver features dual analogue low-pass filters that are hardwired to the left and right signal paths. Thus, Oscillators 1 and 3 pass through the left filter, 2 and 4 through the right filter. Each is controlled via a single Cutoff and a single Resonance knob, although a Split parameter allows their cutoff frequencies to be offset from each other. Being true analogue filters, they don't sound absolutely identical anyway, but Split provides a means to introduce more radical differences to the sound of each channel.

Dave Smith EvolverThe filters may operate in two- or four-pole modes, and sound wonderfully fat and squelchy. The four-pole filter is capable of self-oscillation, whilst the two-pole filter is slightly brighter and more 'in your face'. I felt the two-pole setting should have been a little more responsive to resonance, as the differences between zero and maximum settings were often slight, if noticeable at all. Both filters may be audio-rate modulated by the oscillators that pass through them, which is ideal when you're searching for extra 'sizzle'. There are various preset modulation paths for the filter cutoff frequency, including velocity, key-tracking (positive) and, of course, the filter envelope.

In addition to the low-pass filters, the Evolver features two digital high-pass filters. These may be configured before the analogue filters (in which case they process the external input signal only) or after them, in which position they process the entire signal that has passed through.

Modulation Mayhem

Four LFOs is a generous number, and each has matrix entries for frequency, waveform, amount and destination. All four have a range that stretches from slow (30 seconds per cycle) to very fast (261Hz — middle C in audio terms!), with the range between 8Hz and 261Hz selectable in discrete semitone steps. In addition, they may be synchronised to the current sequencer speed in various clock divisions from one LFO cycle running over 32 steps (twice the maximum sequence length) right up to 16 LFO cycles per step. Waveforms include the traditional collection of triangle, sawtooth, reverse sawtooth, square and random, whilst LFO amount may be set directly in the matrix or may be modulated in turn by another modulation source. As just one example of this, you could vary one LFO's speed using a second LFO whilst sweeping the depth of its effect with an envelope.

Dave Smith EvolverThree ADSR envelopes are provided (with an exponential or linear response); the third one is designated as a free modulation source. Envelopes one and two are hardwired to the filter cutoff and VCA level, although the VCA can also be set to bypass envelope control altogether and 'drone'. As well as Amount and Destination settings, the third envelope has two additional options, delay and velocity, allowing you to offset its start time in relation to the other envelopes and dictate its amount by key velocity.

To extend the modulation routings still further, the Evolver has four fixed controllers: mod wheel, aftertouch, breath control and foot control plus four 'free' modulation slots (Mod 1-4) whose source and destination you may choose. In the case of these latter slots, 24 sources are available (you can use the same source multiple times) and no less than 55 possible destinations are offered for both fixed and free modulation use. I hope you'll forgive my not listing all of these or trying to convince you of the pleasures to be had experimenting with them. If complexity and near-modular connectivity appeals to you, the Evolver is a synth you shouldn't dismiss lightly.

Some of the modulation sources available to slots Mod 1-4 include audio-level signals such as noise and the digital oscillators. The manual warns that some destinations won't be able to keep up with these but I like the philosophy behind the line that states 'but it's fun anyway'. As a final note, the free modulation slots are not filtered or smoothed at all — but the fixed ones are. So if you want to program, say, a filter sweep using an external MIDI controller, you get the smoothest effect by using one of the fixed modulations — for example our old pal the mod wheel.

The Sequencer

The Evolver's sequencer is surprisingly flexible given its unimposing physical presence. As I've already mentioned, it consists of four rows or sequences, each sequence/row being of any length (up to 16 steps) and routable to control practically any Evolver parameter. Direction is always forwards and sequences can be transposed by incoming MIDI notes, or transposition may be disabled entirely.

Programming the values for each step is easy enough. First, you enter Sequencer mode by pushing the dedicated button. Then you select the sequence row you want to program, and turn the knobs either during playback or whilst stopped. If you program the steps when the sequencer is stopped, each turn of the knob triggers the envelopes so you can hear the notes that are generated. As there are only eight knobs, you access values in the second half of the sequence by pushing the lower row button; the knobs then control steps 9-16.

When a sequence is routed to oscillator pitch, each increment of the knob corresponds to a quarter tone. I'd personally have preferred to use semitones (because it's easier to remember the intervals) but I guess this could be handy for more exotic or non-Western tunings. For simplicity, you can also program values for each step via MIDI input. To do this, you hold down the Sequencer button for a moment until it begins to flash. Then as you play each note, the sequence stores its value and advances to the next step.

Each step transmits a range of values from 0-100, and if you turn the knob past 100, the display indicates 'rst', meaning this is the end of the sequence. So, to create a seven-step sequence, you turn knob eight until it says 'rst'. In the first row/sequence (but only in this row), a value of 'off' is also available, which means that no trigger will be sent to the envelopes.

On the subject of triggering, the Evolver may be played via the internal sequencer, via MIDI, or both. Alternatively, an external audio signal can be used to drive the envelopes or step the sequencer. In fact, there are no less than 10 trigger options available: versatility being the name of the game. One favourite trick of mine involves playing the synth via MIDI notes as normal, whilst simultaneously running a sequence controlling several parameters such as oscillator level or ring-mod amount. With such a wealth of triggering choices on offer, it's odd that there is an obvious one missing: there's no means to directly step the sequencer via MIDI notes (although it can be sync'ed to MIDI Clock). Sequences are not currently transmitted via the MIDI output, but this is another feature I'm keeping my fingers crossed for in a future OS upgrade!

Sounds Like

Evolver Programs are arranged in three banks, each with 128 patches. When first delivered, these are organised into categories with sequencer-type material in Bank 1, solo patches in Bank 2 and patches designed for external processing in Bank 3. All of them can be overwritten.

With a three-character display, patches are numbered rather than named, so I found it vital to manually note thelocations of my favourite sounds to prevent overwriting them by mistake. Surprisingly, there is no Patch Compare facility, so when you are saving a patch, it is often worth storing it in a new location so you can be sure your extensive tweaking really has made an improvement before you destroy the original!

As I've hinted, many of the factory sounds demonstrate the more extreme possibilities of the Evolver. Some of them positively scream, howl or roar; I initially wondered if it was possible to tame this creature at all. Fortunately, a number of them are slightly more conventional; some of the warm, brassy solos are especially good. Once I began creating my own patches, I really started to appreciate the power under my fingertips, and was able to create a range of typical monosynth solos, including some very Minimoogish leads. After a while, digital basses, bells, cutting sync sounds and gnarly guitar-like patches all started to spill from this tiny box as I began systematically replacing the factory sounds with my own. The digital waveforms hinted at powerful organs and electric pianos and cried out to be used polyphonically. Which brings me to...

MIDI & Global Functions

This is the point in the review where we speed through the remaining areas. You know what I mean: all the stuff you know is going to be present, but which you don't really want to read much about. There is something that deserves a mention, though: Poly Chain. This allows you to build up a polyphonic Evolver system — providing you have multiple Evolvers to connect together, of course! The other parameters include Patch and Bank Select, Volume, Transpose Amount, Tempo, MIDI Clock source, Input Gain and Tuning, plus MIDI Channel and Dump parameters. The only other thing I'll say here is that the Evolver transmits its parameters via SysEx, not MIDI control changes.


Evolution works in tiny steps, and synths rarely come tinier than this. The user interface is a logical way to keep costs down, although it's never a wholly satisfactory replacement for a bank of dedicated knobs. Even so, it's a workable compromise, and with practice you can zoom around it pretty well. Emagic Sound Diver users can download an adaption to edit the synth on-screen from the Dave Smith web site, and Peavey PC1600X owners can grab a profile too. I'm sure more software will follow, including, I hope, that much-anticipated means to send user waves to the synth.

What really counts is the Evolver's sound and sound-mangling potential, and there is an almost indecent range of options to handle both. The analogue oscillators and filters perform well, and the digital side of the instrument really extends what you can achieve. Cramming in a sequencer is a bonus, and opens up a host of possibilities for synchronised, dynamic changes. Or it can be used to sequentially chop and dice an input signal. When listening to some of the factory sequences playing four-part harmonies and the like, I did occasional double-takes, and needed to remind myself this was 'only' a monophonic instrument. And quite apart from the synth capabilities, those twin audio inputs, delay lines, and the many different ways to transform a harmless signal into a heart-rending wail of terror make this one mean mother of an audio processor. You could buy one just to frighten the neighbours with, if you're that way inclined.

For me, the only downer associated with the Evolver was the fault of Her Majesty's Customs officers exercising their duty (in a very real sense!). I advise that at the very least, you surf along to the web site to hear the demos, and perhaps download the Evolver's manual too. I'd sum up by saying this synth represents one of the happiest marriages of analogue and digital technology I've encountered.

infop.gif See the 'Pricing & Availability' box above.
infot.gif Dave Smith Instruments +1 707 963 7006.

Pricing & Availability

To keep costs down, the Evolver is currently available only from Dave Smith's web site — so aside from listening to the examples located there, there's no way to check it out before you buy one. You certainly won't be able to pop down to your local music store to try one.

If you live outside the USA (even in Canada), the Evolver costs $500, which includes a charge for worldwide delivery via UPS. However, this amount does not include customs duty or local VAT, which may be payable before the Evolver can be delivered to you. In my case, paying Dave Smith for the Evolver (which I did via credit card, and which translated to about £330) was the easiest part of the transaction; I was then alerted by UPS when it arrived at UK customs, and informed that duty was payable. In the end, it cost me about a further £80 (25 percent of the price of the synth) to get it through Customs and into my hands. Despite this hike-up to around £410, I still feel I've got value for money, even if Her Majesty's Customs ended up with a large slice of it! Of course, the exact amount you pay may vary depending on where you live.

If you're lucky enough to live in the USA, you'll obviously avoid the customs situation, and the Evolver will cost you a slightly reduced $475, including US-wide shipping costs.