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Saturday, October 20th, 2018 11:49 pm

Synth Glossary

Granular Synthesis:
The sound is split into small chunks called granules. These may then be processed in various ways to acheive various effects - for example, to stretch a sound (timestreching) the granules will be played back so as to overlap each other. An interesting effect can also be obtained by playing the granules backwards....

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Korg Poly Six
The keyboard of the PolySix is five octaves, C to C. It operates in three different modes, Poly, Unison and Chord Memory. Poly is the normal mode. The instrument gives you control of six notes at one time, and it steals the first note played whenever you play more than six notes. Each of the six notes has a single VCO, a VCF, a VCA, and an envelope generator associated with it. In Unison mode, all six VCOs are stacked up on one priority, multiple triggering. It would have been nice to have seen single and multiple triggering given as an option but you can't have everyting. One nice thing that happens whan you're in Unison mode is that the oscillators are automatically detuned by a slight fixed amount to give you a really fat sound. The Chord Memory function lets you build six-note chords, which you can control from the keyboard, moving them around in parallel, monophonically. A Hold swith has the same functions as on the Mono/Poly - it defeats the release portion of the envelope generators, and also functions as a control with the Chord Memory button to allow you to stack up notes that are too widely spaced to play physically at one time. A not so obvious plus to this feature is that you can give notes emphasis in a chord that's been put into Chord Memory by striking the notes you want empahsized more than once with the Hold switch on.

The Left-Hand Controllers
These are two wheels: pitch and modulation. The range of the pitch wheel is adjustable (tunable), and the modulation wheel adds to the amount of modulation programmed into the preset. As with the Mono/Poly, the center detent in the pitch wheel was a bit too mushy for our taste, but you could probably live with it. And like the Mono/Poly, there is a dead-band area around the center detent to overcome any inconsistency in the mechanics of the wheel.

The Modulation Generator
The output of the MG is a triangle wave. Three knobs, a three-position switch, and a LED are in this section. The LED indicates the speed of the LFO. The first pot adjusts that speed. The second pot introduces a delay between the time that a key is depressed and the time that the modulation is introduced. The last pot is for adjusting the level or intensity of the modulation. The modulation wheel adds to this initial level control. The switch controls the routing of the modulation, which can go to the VCO, the VCF, or the VCA. It might have been nice to have seen combinations of the above routings, but the machine sounds quite good without them.

The Output
Just above the left-hand controllers are the output-section controls. You can switch the single-output jack to off, low or high level. Like the Mono/Poly, when the output is off, the headphone output remains on, which is useful for adjusting thins in the privacy of your own ears.

The Oscillators
There is an overall tuning control with a range of about a half-step just to the right of the output section, and next to that are the oscillator controls. These include an octave switch (16', 8', 4'), a waveform-selector switch (sawtooth, variable pulse width, or modulated pulse), and a control that serves double duty as a pulse-width/pulse-width- modulation amount control. When you've selected the variable pulse-width setting on the wave-form selector switch, this pot serves to set the duty cycle of the pulse wave (50% at 0, narrowing down as you move the pot up). When you've selected the modulated pulse setting on the waveform control, the pot serves as an intensity control for the pulse-width modulation. Next to that control is a knob for setting the pulse-width- modulation speed. The source of modulation for the pulse-width mod is an LFO (it puts out a triangle wave) that's independent of the MG. That's very useful for fattening up the sound of the instrument, since the two LFOs can be set to different speeds. Next to the pulse-width-modulation speed control is a three-position switch for turning on a suboctave, which can either be one or two octaves below the oscillators.

The VCF
There are six 24dB/octave low-pass VCFs under command of this single set of filter controls. The controls given are cutoff frequency, amount of resonance (the filter oscillates quite nicely), -+ envelope-generator intensity, and keyboard tracking. Like the Mono/Poly, the keyboard tracking is 100% at about 7 or 8 on the dial, and about 150% at 10 on the dial.

The Envelope Generators And VCA
Each voice has a single ADSR envelope generator to control both the filter and the VCA simultaneously. The VCA can also switched to an on/off type of organ envelope, which turns on when a key is depressed and off when it's let up. This is useful if you've got the filter envelope doing something unusual. In the VCA section is an attenuator, a stepped pot. This is a programmed volume control for use in matching the output levels of different programs. It works in steps of 2dB both positively and negatively.

The Effects
This section is used to fatten up the sound of the instrument still more. It offers chorusing, phasing, and an ensemble sound. There is a speed/intensity contorl that serves double duty depending on what mode the section is set in. For chorus or phasing, the control serves to set the speed of the effect. For ensemble, the control is for setting the intensity of the effect. This section again has a separate LFO, which with the separate LFO in the modulation generator and the separate LFO in the pulse-width- modulation section lets you really thicken the overall sound of the instrument, thereby overcoming most of the potential wimpiness inherent in single-oscillator instruments.

The Arpeggiator
The arpeggiator has its own LFO for determining its speed. The range is adjustable - either one octave, two octaves, or full, which extends across the full range of the keyboard. It will arpeggiate up, down, or up and down. And like the arpeggiator on the Mono/Poly, you can add notes to the arpeggiation when it's latched by holding down at least one note and playing the new note or notes you want added, then lifting up on the keys and playing a new set of notes when you want to change the chord.

The Memory
There are four banks of eight programs each that are user-writable. The sections that come under memory control are the VCO, the MG, the VCF, the envelope generator, the VCA, and the effects. The knobs that are presettable are colored white, and those that aren't are gray. Each program and bank switch has an LED in it. There are four bank switches (A, B, C, D). A switch is given for putting the instrument in manual mode (where thepanel controls are all actively controlling the sound), and another is provided for writing programs into memory. Editing programs is accomplished by just moving a pot or a switch. When a pot is moved, it incrementally changes the value in memory, until the output limit of the pot is reached. Then it jumps to the absolute value (the actual value) as shown by the pot. To get back to any preset value, you just hit the preset number switch again. There is a write-protect switch on the front panel too. A cassette interface is provided on the instrument for saving and loading extra programs. The bank, manual, and write switches sere double duty for the cassette interface. These controls, when the tape-enable switch is enabled, serve as To Tape, From Tape, Verify, Error/Cancel, Found, and Loading controls and/or indicators. Time for loading and unloading from and to tape is about seven seconds, very fast as cassette dumps go.

The Back Panel
There is a power cord, posts for wrapping the power cord around, an on/off switch, an audio-output jack, a head-phone jack, a control-voltage input jack to the VCF's cutoff frequency, a trigger input for the arpeggiator, a switch input for turning the chord memory on and off, and input and output jacks for the cassette interface with level switches (high and low). This latter is a welcome addition to any cassette-interface system. Note, however, that there is no provision for controlling the VCOs externally. Dimensions are: 39 1/4" long x 5 1/4" high x 15" deep; 25 1/4 lbs.

Conclutions
The PolySix sounded a lot nicer than we expected it to given that it has a single oscillator per voice. The string orchestra sounds were especially rich. All of the independent LFOs do a lot to fatten the sound up. The filter when it's set to resonate has a very haunting quality, and coupled with the keyboard tracking, you can use that high Q sound as if it were another oscillator. The suboctave generator helped fill out some of the sounds too. For an inexpensive programmable polyphonic instrument, it doesn't look all that bad either, and it's built fairly sturdily (metal front panel and wooden exterior). If you're looking for a programmable polyphonic to beef up your act and you're on a limited budget, the PolySix may be just the ticket.

Hosted by Jesse Mullan