Digital costs 20 quid, and is a unique frankenstein-style amalgamation of various digital waveform-bending synthesis techniques, stuck together in such a way that not only do they compliment each-other, but they also interact in interesting and useful ways.
18 base waveforms are available, but these can be doubled up, like in the Casio CZ synths, so that you get one cycle of (say) sawtooth, and then another cycle of square. Silence and noise are not excluded from the party, and a waveform which consists alternately of a sine wave and blasts of white noise is possible - a pretty unique thing! - and this suggests the kind of oddball digital mayhem this synth is set up to make.
Each of the four oscillators gets it's own phase distortion shaper, but unlike the vast majority of 'PD Synths' which give you the phase distortion model championed by Casio - a model which has tunnel vision in that it bends sine waves (well, cosine waves, if you want to get technical) with a view to creating the sound of a sweeping lowpass filter, Digital lets you feed any single or compound waveform in, and use any phase distortion function on it (you are limited to five control points, which is more than enough to open a universe of interesting sound). Map the PD level to the modwheel or an LFO, and you have extreme PWM type sounds, frothing waveshaper type effects, Casio twangy plasticity, and morphing tones reminiscent of wavetable synths.
The author had the insight to provide six preset shapes for the PD function, and the names of them are the waveform you get out if you feed it a sine wave - but of course you don't have to feed it a sine! This means that by flicking through the countless oscillator waveforms, six preset PD shapes, and messing with the PD depth, a huge range of tones can be created right off the bat by someone who is averse to in-depth tweaking.
Asif that weren't enough, we have a feedback control and multimode resonant filter for each oscillator, distortion, as well as several other controls, and the resultant four sounds (post PD, filtering, feedback and everything) can be used as operators and carriers in one of several 4-op FM and ringmod setups! Ladies and gentleblokes, we have arrived in tweaker paradise! Please fasten your seatbelts and remain in your seats for touchdown...
As an example of how interactive the various stages of this synth are, consider the feedback knob, which seems to be applied last in the signal chain, so that the filter - instead of filtering out the feedback when you lower the cutoff, gets caught in the feedback loop, creating unique resonance feedback effects which really extends the tone of the filter. The feedback can also create wave morphing, turning a triangle wave into a sawtooth for example. The only pitfall here is that turning the knob a hair too far results in unpredictable cascading digital noise - not a fault of the synth by any means, but it can be awkward. Luckily we have an excellent, comprehensive modulation matrix for very specific modulations, capable of reining in the digital beast. I found for example, that by setting things up so that when the resonant LPF was closed, the feedback was high, and when the filter was open, it was low, I could maximise the effect of the feedback, without falling into the 'abrasive digital noise' trap.
Sound quality is good, with something unique about it - it has a bit of warmth - it has soul. There is some aliasing if you play very high notes, but an acceptable amount, and to an extent this is part of the instrument's character (it's called Digital and not Analogue for a reason ;). Luckily, the types of animated tones Digital produces tend to sound best in the bass to high midrange range. If you play very high notes, you won't hear all those moving harmonics, so it's a bit of a moot point, perhaps.
The GUI is quite plain, as per the CoFX canon, however, I appreciated the ability to add my own colour scheme to the synth and change it at will. I like using certain colours to get me in certain moods, so this breathed some life into an otherwise rather drab GUI for me. At the very least, it is set out in a logical way, which facilitates ease of use, which is the most important thing.
In a way, I see this synth as a sort of spiritual predecessor to Blue, and actually the morphing waveforms reminded me a bit of my love affair with Zebra. All in all, for the price you pay for it, Digital is a steal, and one of my favourite CoFX synths to date. It has that tweakability and hands-on experimentation which keeps you hooked, and a unique feature set and structure that I don't think I've seen anywhere else ever.
What is less appealing that an 4 operator synthesizer? Days of cheesy (in the worst sense) game cards or last gasp Yamaha DX27/100 clones. You name it, it doesn't sound all that good. If nothing else, I hope this review convinces ConcreteFX to change it's marketing strategy and give it a sexy re-write on it's information.
If unike me, you actually had a look at the feature set then you'd know Digital is anything but a throwback to boring FM synthesis. Instead Digital is an exciting synthesizer in all senses. Yes, there is a 4-op FM engine but it goes in directions far beyond a lot of FM synths try to do and this is something that is great about ConcreteFX in general. They make solid synthesizers at reasonable prices with feature sets that make one wonder how they got into that modest sized interface.
Interface: Everything you need is on the interface or one of it's multiple tabs. Click on a tab and you're at the FM algoithym page, move to another and you're at a 8 track step sequencer. Everything is in one screen and it's easy to learn and easy on the eyes.
Synth Engine: 4 operators with 15 algorithms, phase distortion synthesis and waveshaping, 10 filter options, one per the four oscillators available. 18 waves to run the FM OSC through, 8 envelopes, an extensive modulation matrix, excellent effects and high quality sound. No one can say Digital is lacking for features.
Sound: Excellent and expansive come to mind. There are multiple synthesis techniques that expand upon another while not getting in the way, simplicity to complexity in ways that make 6-op FM seem almost simple but most important, the sounds are there to get and they are easy to get to. Don't go into Digital expecting to program a masterpiece in 15 minutes, make no mistake this is a programmers synth but also a generous one with 160 patches to learn from. They are good representitives of Digital but it is your sound that will matter once you get the engine down. And the sound engine is pretty easy for such a complex synth.
And So?: Recommended on all fronts. Moderate learning curve, lots of features, a good amount of presets and of course great sound make Digital a easy to like synth. At $65 it's a whole lot easier to afford as well.
ConcreteFX have created their own interface which has been used successfully in all their synths with some variations as neeeded. Learn Digital and you have a major advantage on other ConcreteFX synths.
This is a winner in a lengthly winning streak for ConcreteFX. If you like digital sounds they are here. If you like the way you can take digital and soften it up and do twisted things normally thought of with samples, it's here. Either two features would make any competent synth worth your purchasing attention. To have so much firepower at your disposal for such a reasonable price is extrodinary.
Try it, learn it, this and most ConcreteFX synths I am familiar with are equally worthwhile, a fact many are starting to realize.