Sean Rothman, armed with jack lead and MIDI cables, assesses two newcomers from Korg and Sequential Circuits.

The polyphonic synthesizer market has undergone unprecedented expansion in the last two years, directly as a result of the enormous advances made in semiconductor technology which has sent prices tumbling. Allied to this has been the terminal decline of the monophonic synthesizer — after all, who wants to play one note when for comparatively little extra they can have six or eight voices to play with?

Two recent arrivals in the UK marketplace have been the Korg Poly 800 and the SCI Six-Trak. Although they have a certain amount in common and both share a similar design philosophy (to make a high quality cheap polyphonic), the two manufacturers have taken quite different paths in achieving their aims.

Black and White

The Korg Poly 800 is a strange looking beast. The case is made of gunmetal-coloured ABS plastic similar to that found on the Teac Portastudio. The keyboard is a full size four-octave affair and is typically Japanese — ie better than the Italian variety but not as good as those of American manufacture. You can have the white notes black or the black notes white, that is you have a choice of keyboard colours.

The 800 is very light and is helped by having an external mains supply. Mains supplies are always the heaviest component in a synthesizer and its exclusion allows the user to play his/her keyboard with it strapped around the neck á la the Roland SH-101. To be frank, the 800 is quite flimsy and you'll really need a hard case for this one if you intend to gig with it.

The Korg uses an incrementor system, a development that first appeared on the Moog Source, although Korg's own Poly 61 was the first cheap poly to utilize it. Basically the system works by assigning each control parameter a number and range of values. For instance, the filter cut-off is 41 and it has a value range of 0-99. When you wish to alter the filter setting, you simply type in 41 and lower or raise the value as desired by pressing the 'value up' or 'value down' button. Simple, N 'est cest pas? All of this activity is displayed in the six digit LED readout — the first two digits display the program number and the other four the parameter number and its value.

The advantage of this is that settings can be written down in numerical form, each parameter having a precise value and ensuring you get the right sound every time. This is a lot easier than trying to remember the position of a rotary knob or slider, but much harder to use in a live performance situation (ie gig). Personally, I find incrementors take a lot of enjoyment out of performing — can you imagine Billy Curry doing his stage gyrations over a numerical keypad?

The 800 can function either as an eight voice with one oscillator-per-note (whole mode) or as a four voice with two oscillators-per-note (double mode). The two oscillator banks have an envelope generator each as has the VCF/noise generator. The interesting bit is that the EGs are six stage — not just ADSR but Attack, Decay, Break Point, Slope, Sustain, Release — ADBSSR! This can create some very interesting effects but this development has been at a price and a very significant one — there is only one VCF for all eight voices. This means that no individual note can be triggered without any other held notes being retriggered also. This went out of fashion years ago and I hope that other manufacturers are not tempted to follow Korgs' example just to keep unit cost down. It would be a retrograde step.

Despite this limitation the Poly 800 is quite capable of making high quality sounds even though the ones contained in its 64 memories are somewhat less than inspiring. It's great for string and brass sounds but is difficult to get anything that's novel and musical out of its circuitry.

The Poly 800 can run off batteries but this feature is of debatable value. A brand new set lasted just four hours — work out the cost of that for a world tour! This is a more fundamental problem than it might appear in that in their infinite wisdom, Korgs designers did not include a separate supply for the memory. Guess who left it on overnight...!

The Poly 800 is an ingenious instrument with a number of features geared to its extremely attractive price. The KBD filter tracking could be improved and a smaller keyboard needs a player who can adapt. But despite a few idiosyncrasies there are no major omissions and some unexpected bonuses: the sound parameters are more extensive than those of the Poly 61.

Like the JX-3P the Korg has its own onboard step-time sequencer. I'm not a great fan of step-time so it doesn't interest me much, but I know a lot of people will find this useful. It also has chord memory and MIDI.

The Main Attraktion

The Six-Trak is the latest keyboard from Sequential Circuits, the people responsible for that industry standard, the Prophet 5 and more recently, that rich man's (and woman's) plaything, the Prophet T-8. The Six-Trak is designed to be used as a complete system with the SCI Drumtraks, but as we reviewed that last month we thought we'd see how it fared on its own.

The Six-Trak is very well finished in the SCI tradition and carries on the family styling relationship. The control panel looks quite spartan — well, uncluttered's the polite word. The end cheeks are finished in the inevitable wood — surely SCI are aware by now that gigging musicians would sooner have a practical finish? The keyboard is cheap, but not unpleasantly so, and spans a full four-octaves.

Complete Control

The Six-Trak also uses a form of Digital Access Control and this is the first time SCI have used this system. This is purely to keep the unit's price down, and the Prophet series will continue to use knobs.

The parameter values are altered by a continuously variable rotary knob instead of buttons whilst the actual parameter data is entered via the usual numerical keypad. The buttons on this pad are made of a spongy plastic material similar to those on the Spectrum computer, but these are quite adequate.

VCO's or DCO's — That Is The Question

The oscillators are VCOs instead of DCOs which makes the Six-Trak a member of that endangered species, the analogue. Combined with the four-pole filters (good news — there's six), this means that the Six-Trak is great for quasi-Prophet/Oberheim sounds but not so hot at the more fashionable thin sounds that the Japanese excel at. So it's really a matter of taste as to whether you like the sound of the Six-Trak or that of the Korg.

Every Which Way But Loose

There is an arpeggiator, another species facing extinction, but it's more interesting than most in that beside the usual up/down mode, it has an assign mode. This plays keys back in the order that they are entered, so you can program a hookline very slowly, turn the speed control clockwise and play it back faster than any budding virtuoso could hope to do.

The most interesting aspect of the Six-Trak is its six channel capability from whence it gets its name. This enables you to layer sounds in 'Stack' mode, so you could play a live solo with six different voices simultaneously. There is also a sequencer and it's this that is the Six-Trak's killer punch. It can record six completely different melody lines (monophonic), each with different voices. This is like having a built-in multi-track machine and the only real drawback is the 800 note capacity but this can be expanded to around 4,000 notes with SCI's Model 64 interface and a Commodore 64 computer. Oh yes, and the sequencer's real-time too!

Backtrack

One thing could be improved upon, the lack of external control sockets, and this applies to the Poly 800 as well. The MIDI's useful if you own a lot of new gear but how about a few CV gates for the poor souls who aren't the recipients of a record-company advance? Also the six channel facility would be more useful if there were separate outputs, which would allow external processing and facilitate multi-track recording.