Every now and then a product appears on the musical instrument scene that causes quite a stir by offering remarkable facilities at an amazingly low price. Two such instruments that spring to my mind are the Wasp and Pro-One synthesisers, both of which offer facilities normally found in synthesisers twice or more their price. The Korg Polysix falls into this category for it has some remarkable features, but costs about a third of the more popular polysynths currently on the market. Whilst there have been technical compromises made on the Polysix in order to reduce costs, that doesn't prevent it producing some classy sounds. These sounds can be stored in 32 memories and should that not be enough you can dump the memories on to cassette and build up your own library of sounds.
As the name implies, the Polysix is a six voice polyphonic synthesiser; that is, it has a separate synthesiser module for each of its six voices allowing independent articulation for each note. The synthesiser module consists of 1 Voltage Controlled Oscillator (VCO), 1 Voltage Controlled Filter (VCF), 1 Envelope Generator (EG), 1 Voltage Controlled Amplifier (VCA) and a number of Low Frequency Oscillators for various modulation purposes. The fact that it only has a 1 VCO per voice might seem to be a limitation but also included on the Polysix is a versatile chorus unit that allows you to create some rich sounds indeed — but more of that later.
The VCOs can be pitched at 16', 8' and 4' and have a sub-octave that can be switched in at 1 or 2 octaves below. Normally I am very wary of sub-octave devices but this one is very effective and adds a lot of depth to a sound. There is a 3-way selector switch which offers sawtooth, variable pulse or modulated pulse waveforms. The Width control next to the selector allows you to vary the pulse width from square (50/50) to nothing (0/100). This is more useful than it may first appear as it enables you to effectively turn the VCO off if you wish to use the filter in the oscillation mode for Syndrum effects or whatever. The modulated pulse has a separate LFO for its sweep and the Width control doubles as a modulation amount control. Having separate modulation for the pulse width is useful as it enables you to have a slow modulation of the pulse width, yet still retain normal vibrato. This means that you can recreate the effect of two VCOs, if carefully set. My only criticism is that you cannot modulate the pulse width with the EG — this can be a particularly dramatic effect and one that I missed. Apart from that, Korg have provided a comprehensive and versatile oscillator section.
The filters on the Polysix are of the 24dB/Octave Low Pass variety and sound good and punchy. Cut-off and resonance controls are provided and the filter can be put into self-oscillation. There is also an EG amount control that enables either positive or negative-going filter sweeps. Finally, there is a Keyboard Amount control which is variable from 0-150% so that the filter can track the notes played on the keyboard. It's nice to see a variable control here instead of a switch as is common on a lot of synths these days. You can use the filter as another oscillator if you wish, or by tuning the filter to the VCOs some impressive bell and vibes sounds can be obtained plus realistic organ sounds.
The EG is a 4-segment ADSR type and has a wide range of attack and decay times. Sustain is variable from 0-100%. The Release also has a wide range but is not linked to any form of footswitch which I think is a small drawback — that would have been a nice performance facility. The VCA is the final link in the chain and has a switched attenuator so that you can preset the levels of sounds stored in the memory, overcoming drastic changes in level as you switch sounds. Alternatively, you could preset a solo lead-line sound to be louder than the other sounds so that it will stand out above the rest when you break into your solo. There is also a slide switch that selects whether the VCA is to be shaped by the EG or a simple on/off gate type envelope.
The Polysix's LFO section has Rate, Delay and Amount controls which can be routed to either the VCOs, VCFs or VCAs, selectable by a slide switch. If you wish to modulate the VCOs and the VCFs, all is not lost because the modulation wheel to the left of the keyboard is permanently connected to the VCOs for vibrato. By selecting VCF on the selector switch and using the modulation wheel, simultaneous modulation is possible. It's nice to see VCA modulation available — this allows some very effective vibes sounds to be created. The output of the LFO is only a triangle type waveform for vibrato, filter sweeps or tremolo effects (but not trills). Should you wish to modulate the filter with another waveform, there is a socket on the back for external modulation of the cut-off frequency.
All the six voices are internally mixed and are fed into a chorus unit. It is this that transforms the Polysix into a very powerful beast. It offers three modes of operation and can also be switched out if so desired. It can be a chorus unit or a phase shifter, in which case the variable control varies the speed of the effect. When switched to act as an ensemble device this control alters the intensity of the effect. This section is programmable and when used in conjunction with the modulated pulsewidth and the LFO, enables you to store some fine orchestral textures in the memory.
Also on the instrument is an Arpeggiator which allows you to have cascading patterns of notes travelling up, down or up and down over 1 or 2 octaves or the full range of the keyboard. You can latch the Arpeggiator which means that you can take your hands off the keyboard leaving them free to alter controls, play another instrument or make a cup of tea while the notes zoom up and down. The Arpeggiator has its own clock (variable between 0.2 and 20Hz) which means you don't have to use up the LFO facilities to set its speed. The Arpeggiator can be triggered by a rhythm machine, sequencer or Synclock via a socket on the back.
As if these facilities weren't enough, there is a bank of buttons to the right of the instrument that enables you to store up to 32 of your own sounds in 4 banks of 8 locations in a computer memory. Storing a sound is simplicity itself. You push a slider switch (located to the right of the 8 memory selectors) to 'Enable', and the red Write button will now begin to flash. You then press the grey Manual button followed by the bank and memory selector buttons to specify the preset location, whereupon the LED on the Write button will go out and the sound is stored. By pushing the slider switch back to 'Disable', the sound is protected from erasure.
The control panel is in permanent Edit and should you feel that the sound you have just recalled from a particular memory needs a slower attack or more filter sweep you simply move the appropriate control until you are happy with the sound. If you want to store the updated sound, you just go through the Write procedure but instead of pressing the Manual button, you only press the relevant memory location buttons and the updated sound is stored. If you don't want to store the revised sound, you simply press the memory location buttons and the sound reverts to its original state.
Storage and editing of all the synthesiser functions (except the Arpeggiator) is done with the memory circuits and sounds can be 'dumped' on to cassette, in which case the 4 bank selectors double as 'To tape, From tape, Verify, Error/Cancel' switches (upon selection of the tape interface slider located to the left of the top bank of buttons). Although I've not tried this procedure it is reputed to take only 8 seconds to dump and retrieve sounds to and from cassette.
The Korg also has a key assign mode. There are 4 buttons associated with this section which are 'Poly' which puts the keyboard into the polyphonic 6 voice mode. 'Unison' puts all 6 voices under control of 1 key for some stunning lead line sounds. 'Chord Memory' allows you to play a chord and hold it so that by playing only 1 note the chord remains constant. This is particularly effective with intervals of a 5th and an octave. 'Hold' as the name implies sustains any notes indefinitely.
Finally, to the left of the keyboard are 2 wheels, one for injection of vibrato as described earlier, the other for pitch bending. This latter wheel has a variable sensitivity control so that you preset your bends very precisely to a tone, a third, fifth or whatever. These are generally comfortable to use and a great improvement on KORG's usual joystick but I share Dave Crombie's view in his review of Korg's Mono/Poly (E&MM April 1982) that it is difficult to tell whether or not the wheel is back at the centre of its travel because the detent is so weak.
In appearance, the Polysix is a smart, professional looking instrument that is not too dissimilar to a Prophet 5. The control panel is blue and the casework is a smart wood finish, with brackets on the back of the instrument for winding the mains cable around. The Polysix is very sturdily built and it's good to see that no compromises have been made in its construction.
I think the Korg Polysix is a winner. It is capable of producing rich orchestral sounds as well as delicate solo sounds. The programmable section makes it ideal for stage and studio work alike and the edit facilities make it very flexible indeed. I must admit that, although I appreciate the usefulness of memories, I feel that some people don't explore the full potential of a synthesiser equipped with such facilities. Instead they select a memory as an easy way out. I have heard many reports of Prophets, Jupiter 8s, etc. being returned for service with the original factory presets in them, not one original sound anywhere. This probably explains why so much synth music sounds so similar these days. I just hope that people take the time to explore the Polysix and not rely on the factory presets because it is capable of producing a wide range of sounds.
My only criticisms are that I would like to have seen a noise generator and polyphonic portamento included. The Arpeggiator trigger input is not directly compatible with ARP, Roland or Seq. Circuits but may be interfaced using the Korg MS-02 Interface or E&MM Universal Trigger Interface.
All in all, though, I give Korg full marks for producing a great synth. It has all the right features on it and I personally prefer it to some of the top of the range polysynths I've played. As these synths have all gone up in price recently putting most of them in the £3500 bracket the Polysix, at £1200 or less is a very important instrument and will attract a lot of customers — including me.
The Korg Polysix is distributed in the U.K, by Rose Morris & Co Ltd, (Contact Details).
Review by Steve Howell
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