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Spectral Audio Syntrack

Analogue Filter/Synthesizer By Christopher Holder
Published March 1998

Spectral Audio Syntrack

Spectral Audio's Internet home page includes a large graphic, stating, rather menacingly, 'Rave or Die'. Christopher Holder meets the new Syntrack monosynth and decides death can wait.

Swiss manufacturers Spectral Audio commenced business with the release of the ProTone in the summer of 1996. You may not remember the name, but you'd probably remember its distinctive red, knob‑covered appearance. The ProTone was a paradoxical animal unleashed onto a market enamoured with all things bleepy.

Why paradoxical? For starters, it had an external LFO input but no MIDI Out socket or MIDI control over any of the pots; it also had a ring modulator and a self‑adjusting MIDI channel selector, but no memory patches whatsoever. With 20/20 hindsight Spectral Audio have decided to forget about the quirky, to do away with any lingering homage to a vintage synth past, and give their latest effort mass appeal. The number of people who enjoy coaxing old unreliable analogue gear into life with days of tedious knob twiddling is limited. People want an analogue‑ish sound without all the pitfalls and unreliability of real VCOs (Voltage Controlled Oscillators). People want a digital oscillator, combined with an analogue filter endowed witha suitably plump derriere. People want the Syntrack... or that's the theory, anyway.

If you haven't already cottoned on, the Syntrack is a digital monosynth with an analogue filter. Unlike its predecessor, it has a very tidy MIDI spec and 100 memory locations (expandable to 200, apparently). Under the bonnet are 100 sample waveforms in ROM, and these are all analogue emulations — no bagpipes or marimbas here. No, this is a monosynth that sees the green fertile fields of the dance music scene as its rightful home, where understatement and semi‑modular, multi‑oscillator flexibility plays second fiddle to easily attainable fat basses and screaming self‑oscillating acid squeals. But surely it can't match the raw power of a true all‑analogue machine? — he says rhetorically, with enough ambiguity to compel you to hopefully read on...

Swiss Role

The Syntrack is a smart‑looking blue anodised box, with seven smart‑looking plastic pots. The first four knobs on the left control the filter: Cutoff, ranging from 20Hz to 20kHz; Resonance (we all know what that does even if we can't explain it exactly); Env Mod, controlling the modulation intensity of the filter envelope at the cut‑off frequency; and Decay, which varies the decay time for the filter envelope (from 0.01 to 2.5 seconds). On the right‑hand side of the unit are three controls for the VCA (Voltage Controlled Amplifier). The first pot is switchable between controlling release on the one hand and the decay of the amplitude envelope on the other, effectively adjusting the length of note in two different ways (attack and sustain are fixed); the second pot, Distortion, overdrives the VCA; the third of this set of three is the Volume control, which is self‑explanatory. Each of the pots has a green LED above it to show whether that parameter has been tweaked (on for untweaked, off for tweaked), while all illuminated LEDs throb psychedically if you've cajoled a particularly gutsy sustained bass sound out of the Syntrack (the manual advises that this is nothing to worry about).

Six buttons on the left of the unit, in conjunction with a 2‑digit LCD display, handle the rest of the unit's operations. The display also registers note on/off data with a single red LED. The only problem with the buttons is that they don't scroll continuously through the values if held down.

The back of the unit hides a socket each for MIDI In, Out, and Thru, an audio out on a quarter‑inch balanced jack socket and an identical socket for an external audio input. The Syntrack takes a regular external 9v wall wart power supply.

I turned up my power amplifier and explored the lower reaches of the Syntrack's bass end, and the results were brutal.

Internal Affairs

Inside, there are 100 digital waveforms awaiting your enjoyment. You'll discover the familiar sawtooth, square and various pulse waveforms, as well as many variations of analogue sounding organs, clavs, ring‑modulated waveforms, and clanging FM synth‑style timbres. You can scroll through the options and save the results to any of patches 31‑99, with the first 30 memory locations being non‑volatile. The Syntrack boasts one LFO, which is accessible in the Setup pages and is set globally. LFO frequency is adjustable, as is LFO depth, while LFO Sync locks the LFO to MIDI clock messages sent by your sequencer (fixed to each 8th‑note). The LFO modulates the pitch only and is activated from the mod wheel of your controller keyboard (or MIDI controller 1 from your sequencer). Elsewhere in Setup, you have options for incoming note velocities to control filter cutoff or the severity of the distortion, in preference to more conventional volume control. Furthermore, a Retrigger switch toggles on and off to dictate whether the filter envelope is retriggered on overlapped (legato) notes.

As mentioned earlier, the Syntrack's MIDI spec is more than tidy. Every knob you see on the front panel transmits controller messages, and the Syntrack happily recognises those messages when your sequencer plays back that information. A neat addition is the printing of the applicable controller number under each pot — MIDI implementation charts are great fun, but I'd gladly leave them as bedtime reading and have these printed numbers to consult while in the studio!

Pass The Source

When I first powered up the Syntrack and plumbed it into my studio, I was a little underwhelmed by the results. Tapping away around middle C, I began moving through the 100 presets. Almost without exception each sound had a short decay and little variation — it was like an uninspiring selection of '80s sequence/arpeggiator fodder. At that stage I suspected that it was going to be tough to find any redeeming qualities about the Syntrack, and I knew I'd probably never be let back into Switzerland.

In the Syntrack's manual, Spectral Audio profess to use a wavetable oscillator, but before you get any bright ideas about constantly evolving timbres and endless editing possibilities, I must insert a caveat. The 100 waveforms are definitely in the digital domain, but they appear to exist as samples in ROM. The waveforms have the distinctive buzzing character of something that's been produced by a Wavetable synth like a Waldorf Wave or Microwave (and may indeed have been recorded from such) but it's a bit misleading to present the sound source as a wavetable oscillator. It's almost of some interest to note that if you scroll quickly enough through the internal waveforms while holding a note down, you can actually get something that sounds like a real wavetable patch.

Unfortunately, a lot of the waveforms haven't been stored with the utmost care, and when they're played back you can often hear a clearly audible 'halo' of high‑pitched noise around the note before it's gated. This associated noise could be attributed to any number of A/D and D/A conversions in the acquisition and/or playback of the waveform, but it's worth noting that it's there — not on all the waveforms, but on quite a few. On the higher notes the hiss is masked, while if you've assigned the Syntrack to bass duties you can lessen its impact markedly with a judicious bit of high‑end cut with your EQ.

Plumb In The Depths

Just when I was beginning to despair that there was nothing to salvage from this review I turned up my power amplifier and explored the lower reaches of the Syntrack's bass end, and the results were brutal. The Syntrack does indeed have a bottom end to fall in love with.

Syntrack call their analogue filter a 'Moog' filter. This is a little vague, to say the least. Moog filters were invariably four‑pole (24dB per octave) and the revered Minimoog is often credited with the fattest bass sounds in Christendom. Whatever its exact specifications, the Spectral Audio filter has much to commend it — the sound it can produce when provoked is immense. A great bass sound should have character and unlimited bass‑end welly, and the Syntrack is able to produce these timbres seemingly on tap. It has a brilliantly quick attack, which gives the basses a fantastic snappiness. In fact, such is the response that, without much thought, you can DIY a kick drum that will rival a TR909 or 808 for thudding impact — grist for your sampling mill. Virtually all of the 100 presets have a great bass end, and even the sounds with heavy resonance maintain a solid low‑end integrity.

Swiss Cheese

In truth, the sounds you can achieve further up the keyboard aren't necessarily as bland as the presets would suggest. Give the sound a bit of decay and with some work you'll find an interesting lead line. The resonance on the Syntrack is capable of being driven into self‑oscillation, and that, coupled with the analogue distortion control, will give you a selection of interesting and chirpy incidental acid sounds. But remember that ultimately you're limited by having only one oscillator, and the nature of the Syntrack's filter gives the high end quite a bit of transparency, so don't expect any ultra‑dense screaming lead lines.

The Syntrack is going to be a different voice in your studio — I can almost guarantee you that.

The Syntrack's upper register exalts in its cheesy, '60s, battery‑powered organ sounds, and for me this is nothing to be ashamed of. With the resurgence of tacky film‑score textures in trip hop, and ravers trading in their plimsolls for slip‑ons at 'lounge‑core' nights, a good range of organ‑like sounds will be as essential as your velvet tux. The principal catch is that, since the Syntrack is monophonic, you can't play chords, but with a little help from your sampler you'll be ready for that Marv and the Magi‑tones audition.

As the Syntrack's filter is so responsive, you might find the external input more useful than you'd think. Amongst other things, I routed my Novation BassStation through the Syntrack, with some interesting results. Switch the Syntrack to a blank patch and have the external source triggering the filter via MIDI to call its filter into service. Turn the resonance on the Syntrack past the 12 o'clock position and it's transformed into an intergalactic star destroyer, firing photon torpedoes. This again underlines the point that you'll probably find plenty more useful monosynths, but for the money you'll be hard pressed to find anything more enjoyable.

Mono Magic

The Syntrack is going to be a different voice in your studio — I can almost guarantee you that. When you reach out and give those cute little knobs a tweak, you get results. The sound is transformed — and you can record the tweaks into your sequencer.

I wouldn't buy this synth under the impression that you'll be coming up with killer TB303‑style acid lines (after all, portamento is conspicous by its absence). This is not the Syntrack's bag. It's not a programmer's synth either — the pared‑down editability doesn't allow for real complexity. The Syntrack is more about cheap thrills than exploring a new sonic universe, and there's nothing wrong with that. The filter at times gives the upper echelons of the keyboard rather too shrill a quality for my liking, but the glorious by‑product of this is that the midrange and low end is to die for.

For a single‑oscillator synth the Syntrack has way more guts than it has any right to have. Add some Spectral VCA distortion to the sound and you've entered instant big‑beat and techno heaven. Stack it up against the other monosynth candidates at your local dealer for a comparison. I think you'll be pleasantly surprised.


  • Wild and responsive filter.
  • Great bass sounds.
  • External audio input.
  • Good MIDI spec.
  • LFO MIDI sync.


  • Limited editing.
  • No portamento.


Spectral Audio have built the Syntrack for instant appeal: the bare minimum of controls, a rock‑solid digital oscillator, a responsive and extreme filter, and good MIDI spec. It also happens to have some of the fattest and most playable bass sounds around. Well worth auditioning as a perky new voice in your synth rack.