Siel DK 80 polysynth
Price: £699

SIEL's reputation in the cut-throat world of synthesiser manufacturers has been rapidly growing over the last couple of years. They were fitting MIDI even before many of the big Japanese and American companies, they offered a velocity-sensitive polysynth (the Opera 6) for a price most conventional synths couldn't match, and they updated the design to the very smart DK600 without any of the delays, fuss or bother inevitable from many larger firms.

Interesting, then, to see what SIEL would do next, and what improvements or economies they could make over the DK600 design.

As it turns out, they've made a few of both, but while the improvements are most welcome, the economies may prove exceedingly annoying. It's all part of a trend which many modern synth designs have begun to follow.

Going back a few years, the first cheap substitutes for synthesisers were string and brass ensembles with a single filter, such as the Crumar Performer. The filter gave respectable synth-like noises, but try to play individual notes rather than simple chords and you'd be faced with a choice of re-triggering the filter on all the notes held (pretty unmusical) or not re-triggering it at all (pretty unusable). In other words, nobody knew how to fit enough filters in a small space to give one to each note sounded.

Even the PolyMoog, the first mass production polysynth, had only one dynamic filter, although its static resonators and filter preset boards allowed it to produce very lifelike sounds. Eventually the luxury of multiple independent filters arrived, on the Yamaha CS80, the Roland Jupiter 8 and the Prophet 5, and synthesisers began to sound like something we'd be familiar with today.

With improving technology, it's become possible to offer more and more features for a lower price than anyone would have thought possible ten years ago. This had led to all the cut-throat competition we mentioned, and a desperate search for cost-cutting devices to keep ahead of the opposition.

Sad to relate, Korg found the ultimate cost-cutter on last year's Poly 800, and SIEL have followed their 'lead' on the DK80. Yes, you guessed it - dump the multiple filters and go back to just one shared out between all the oscillators.

STONE AGE?

Apart from taking us back to the stone age, synths with this design needn't be too bad. On the DK80, for instance, you have twelve oscillators, programmable keyboard split or layering, built-in realtime sequencer with two memories playable separately or together, velocity sensitivity and complex MIDI functions. All this is controlled by a digital access method from a pair of Value Up/Down buttons, but unfortunately editing has been made just about as slow as it could possibly be.

Suppose you want to change the release time of a string sound. On a Prophet or something similar you'd just have to twiddle a knob. On the DK80 you have to hit Parameter, look up the right reference code on the right-hand panel on the synth, punch in those two figures, hit Enter, then hold one of the Up/Down buttons and wait for the multifunction two:figure LED display to start cycling through its possible values. Not very practical for stage use!

The sound select works in the same way as the Opera 6/DK600 design, in that you have to punch two figures and then Enter to call up a new sound. At least this part of the system has some point - you can set up the next sound change in advance and access it instantly - but the complexity of the Edit function seems completely pointless.

Let's see what functions you have to edit. Most of the parameters can be programmed independently for the A bank and B bank of six oscillators each, creating two completely independent sounds which can overlap to any degree or play on either side of a keyboard split. If you want to create a patch using two different sounds, you just have to use the Voice A/B switch on the left-hand panel while changing parameters. Then your first section is a VCA with Attack, Decay, Break Point, Slope, Dynamics and Damper. The depth of dynamic response is not variable, but if you do want it switched in it's preset at a very usable level. The damper refers to an optional piano-type dual footpedal which can also control sustain, sequencer start-stop, program up and so on.

The next section is detuning, coarse and fine, followed by Noise Level, then the VCF, which has the same ADBSSR and dynamics On/Off parameters as the VCA; A settings refer to treatment of all the oscillators, B settings to treatment of the white noise (just as on the Korg Poly 800).

Next a section headed LFO 2, which refers independently to the oscillator and noise filters and has speed, initial and final level, delay, triangle/square and Automatic/Modulation Button parameters (no modulation wheel unfortunately). The addition of initial level is imaginative - why assume that you always want modulation to fade up from nothing?

LFO 1, independently programmable for the two banks of VCO's, has the same parameters but only the triangle waveshape - a bit limiting. The DCO section - again referring to the two independent banks - has Split Point (on keys 0 to 61), Sawtooth and Square Waves On/Off, Sawtooth Footage (4, 8, 16) and individual volumes for Square footages of 16, 8, 4 and 2 feet. The VCF section has Cutoff, Resonance, Keyboard Track (off, half or full), Single or Multi Trigger and Envelope Level parameters.

Finally there's a chorus section, individually switchable for the two oscillator banks, which gives lots of movement to the sounds (but as on all other polysynths adds a little hiss as well), and a programmable volume function quite independent of the master volume knob. There are four non-programmable functions marked on the panel - these are Memory Write Enable, Sequencer Clock from MIDI/external click/internal, MIDI receive channel 1 - 15 or All, and left-hand footpedal destination (to Program Up, Sequence Start or MIDI Data Transmission). This last function is useful for cutting off the DK80's effect on another synth or expander.

There are two more non-programmable functions not marked on the panel - these are Sequencer External which allows the sequencer to control an external synth instead of the DK80 itself, and Metronome On/Off for recording sequences. These were probably last-minute additions!

On the subject of the sequencer, it's a useful little tool with looping, the aforementioned metronome, variable speed and clock source and a memory (divided between the two channels) of about 256 notes. You can listen to one pattern while you're recording another over it, and play back one or both sequences with different sounds or the same sound. Patch changes are also recorded.

Finally there's a conventional pitch bend wheel with a fixed range of one tone, a Hold and a single-note Chord button and a socket for a ROM or RAM cartridge which gives an additional 50 programmable or 100 preset memories. The on-board complement is 40 non-programmable memories and a mere 10 user-definable, with a front panel sheet naming the presets. You can refer to the cartridge easily enough, but who's interested in non-programmable memories any more?

The DK80's power supply is separate from the synth itself and clips to either side of the keyboard. It can simultaneously supply an Expander 80 module, which has the same spec except for the keyboard and the split functions - in other words, it can only make one sound at a time.

SOUND QUALITY

Now to the DK80's sound quality. Well, that's what the tape's for, and you can tell for yourself whether or not the sounds will appeal to you. Some of the presets are very clever, and many incorporate stereo movement, the two banks of oscillators coming from separate left and right outputs on the rear panel or headphones. Sounds include Bass/Brass (split), Bass/Piano (layered), Ensemble/Brass (overlapped), Spatial Brass (panning) and so on.

On the other hand, the presets can be improved upon massively, although due to the editing procedure this can be a long process. On the tape, some sounds have been modified only as regards decay and resonance, some more severely. The tape's been multitracked with the Tascam 48 (courtesy of Harman UK) and a Dynamix 16-8-2 mixer, with a Roland MSQ700 keyboard recorder, various digital delays for echo including Roland and Yamaha, and a selection of Vesta Fire effects pedals including flanger, phaser, chorus and distortion.

As you can hear, it's possible to make quite an impressive noise with the DK80, but it takes a while if you want thicker sounds and certain playing styles will be forever lost to you due to the single-filter design.

However, there are lots of good points - the velocity sensitivity, which can be highly expressive both in filter and volume control; the split functions, which extend to layering and overlapped sounds, stereo spread and movement; the sequencer; the complex envelope and MIDI functions. Overall, you can regard the DK80 as two Korg Poly 800s with velocity sensitivity in a single package, and at the recommended price that can't be bad. On the other hand, we shouldn't encourage this single filter business too much - next thing you know somebody will be making synthesisers with only one oscillator.