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Synton Syrinx | |
Article from Electronics & Music Maker, June 1983 |
The Syrinx is a straightforward CEM-chip analogue synth with a 3½ octave keyboard, 2 oscillators (one with a sub-oscillator), 2 LFOs, 2 ADSRs, Ring Modulator, White Noise Generator, 3 Filters and a VCA. It's the filters which contribute most to the machine's unusual sound; there is a 24 dB/octave Low Pass Filter with a Resonance Control, and two 12 dB/Octave Peak Band Pass Formant Filters with their own Resonance controls. As each of these filters can be modulated in different ways and placed at various points in the signal path, some very complex sounds can be created. The sync facilities and Touch/Bend pad are also fairly unusual, as we shall see in working from left to right along the control panel.
Three sockets are labelled at the top left of the control panel, in white lettering on the maroon or black background as is all the other labelling. These are Gate, Keyboard CV and Audio Out. Of these, the first two are stereo sockets, with the tip of the plug carrying the signals out and the ring carrying the signal in. This may prove a little awkward, but it's cost-saving and can be overcome with a couple of special leads. The ADSRs require a 5-volt trigger/gate signal with triggering edges shorter than 0.5mS, but the LFOs can also be reset if a 10V pulse is applied. Normally the keyboard resets the LFOs when in use, but a mono jack plug inserted into the Gate socket can block the reset pulse; this can be made selectable by wiring a footswitch across the sleeve and ring connections of a stereo jack plug. The CV is of the standard 1V/octave kind, and the audio output will also drive headphones down to 125 ohms impedance. The large master volume Out knob is located next to the output socket; there's no facility for an input (for a guitar, for instance) to the filter; this could be added easily enough, but perhaps it's a feature that's simply gone out of fashion.
There are two slow oscillators with individual speed controls, but a shared shape control ranging from sawtooth to triangle to inverted sawtooth. LFO 1 can only be used for Pulse Width Modulation of VCO 2, while LFO 2 also produces a square wave which can only be assigned to modulation of both oscillators. Unfortunately this kind of complexity is typical of the Syrinx, but it is possible to learn to live with it. Each LFO has a rate indicator LED, and the speed of LFO 2 can be controlled at the flick of a plastic toggle switch by the bender pad which takes up the rest of the left-hand section of the control panel.
The Touch 'n' Bend' pad is ugly but functional. It consists of two PCBs fixed at one end and separated by an insulator. When the top PCB is bent down the capacitance between the surfaces changes. This change in capacitance can be used to create a control voltage and hence bend for Osc, Filter or Amplifier. It's divided into two sections, for bend up and bend down, and is astonishingly responsive, giving pitch bends of over two octaves with feather-light control. The bender takes a little getting used to, because it can be set so that the lightest touch or tap on it can cause a very great change in sound. After a little practice, however, it becomes very expressive, but it must be remembered that the one thing it can't produce is modulation or vibrato, except by cultivating a rapid finger vibrato of the type in which only guitarists usually need to indulge.
Three toggle switches in the next column control Auto Portamento, Multi Triggering and One Shot. Auto Portamento, with glide time set by a small rotary, only occurs when one note is held and a lower one is pressed (the keyboard having low note priority). Otherwise portamento occurs at all times when desired. Multi Trig is what is known as New Pitch Detection on the Transcendent 2000, in other words selecting whether or not the ADSRs retrigger on playing a note if a higher one is already held down. Normally this would be left on. One Shot is a feature of LFO 2, causing it to cycle through only once on each key depression. With square wave modulation set to the correct interval, this makes it possible to play a repeated 5th or Octave for instance on each note.
There are three small Bend Assign rotaries, for VCO, VCF and VCA. These allow Pitch, Tone and Volume respectively to be increased or decreased by the touch pad, unless the two oscillators are locked together in Hard Sync. If this is the case, VCO Bend gives a screaming harmonic distortion previously only heard on the Moog Prodigy; an enormously powerful effect if used sparingly. Next to these three knobs are Initial Gain, allowing a 'drone' to be produced if turned up; and LFO 2 modulation of both oscillators, of triangle and square variety. Again this is reminiscent of the Transcendent 2000 in design, and it's useful in some ways to be able to mix the depths of these two kinds of modulation, even if they are at the same speed. On the other hand, it would have been infinitely better to have assigned the triangle modulation to part of the touch pad so that this effect could be introduced in a more expressive manner than by turning a small knob lost in the middle of the control panel.
There are two forms of Hard Sync, Sawtooth and Pulse, and in addition a Soft Sync which tends to lock on to harmonically related intervals as the oscillators are tuned apart. The Sync function can also be turned off so that any interval up to a minor seventh can be selected. To the right of the Sync selector is the octave selector for VCO 2 — minus one octave or plus one to two octaves — and it would have been logical to have had the VCO 1 octave selector to the left of it. In fact, it's to the left and up a bit, next to the Fine Tune control which covers around 3 semitones. The waveshape selectors, at least, are next to each other; they give triangle, sawtooth, square or pulse shapes. Below these are smaller PWM knobs allowing the width of the pulse and square waves to be modulated: as previously mentioned, VCO 2 is controlled by LFO 1 and vice-versa, another odd bit of design.
Five vertical sliders give mixing capability over VCO 1, VCO 2, Sub Octave from VCO 1 (a square wave), Ring Modulator and White Noise. The Ring Mod is permanently fed by the two oscillators, and can produce some useful bell, chime or abstract sounds. The Noise is a little thin and quiet, but all the usual wind, sea and abstract effects can be created with it; there's no random modulation available from it, however.
The Routing control is a large 4-way rotary knob which connects the filters in differing patterns. These are; A, all outputs through Peak Formant and Low Pass filters in series. B, all outputs through Peak Formant and Low Pass filters in parallel, summed at the output. C, VCOs through Low Pass filter only, Ring Modulator and noise through Peak Formant and Low Pass filters in series. D, VCOs through Low Pass filter only, Ring Modulator and Noise through Peak Formant filters only.
As can be imagined, the routing control can produce very great variations in tone, and also in volume. It can't really be regarded as a performance control because the changes caused are often quite drastic, but it does give the Syrinx a lot of the potential of a patched modular synthesiser.
The three Filter frequency controls are adjacent to each other at the top of the control panel. Below them are their smaller respective resonance controls, and below these four modulation depth controls. These are: LFO 2 to the two Peak filters; ADSR 1, positive or negative, to the Peak filters; LFO 2, positive or negative triangle, to the Low Pass filter; ADSR 1, positive or negative, to the Low Pass filter.
These controls can produce very complex sounds, with different depths and directions of modulation together with the different resonance values at different frequencies. Again there's an odd piece of design, in that three of them are at Zero depth in the vertical position, while the fourth needs to be turned fully anticlockwise.
There are two keyboard tracking controls, variable from 0 to 2 (0 to 200%) for the peak and for the low pass filters.
Finally there are two conventional ADSRs, 1 for the filters and 2 for the VCA. These can't be repeatedly triggered by the LFOs, which is a shame, and also the maximum decay times are a little short, being around 7 seconds. There isn't an 'unconditional' option to allow the attack cycle to complete whether or not a key is held down.
Some comment has already been made about the Touch Bender, which is a brave idea and largely successful; a pity the modulation isn't as accessible. Partly due to this latter fact it's tempting to think of the Syrinx not so much as a live performance synth as a studio synth. Synton themselves comment also that "the peak filters can be tricky to work with, although after some practice it will be clear that many new sound effects can be obtained with proper settings"; the average synthesist will have to spend some time getting used to the idea of different moving bands of frequencies within the main body of the sound he's creating.
In the studio at least, the Syrinx reigns supreme for its price. Some extremely complex sounds can be created using One-Shot, different envelopes and Sync Detune, certainly rivalling small modular systems. Not only can it create recognisable synth sounds — such as the Minimoog's powerful 3-oscillator, low note priority trills — but it can also create useful sounds which simply haven't been heard before on an inexpensive synth. Some of these compare very favourably in texture to the digital voices of the Synclavier or PPG, due to the amount of movement within them. After becoming familiar with the Syrinx's oddities this sort of manipulation is within easy reach.
To make up for the fact that the Syrinx, once imported, is a shade expensive compared to the SH-101 or SCI Pro-One, Argent's are offering a special package deal with a Roland CSQ-100 sequencer, a 2 x 84 note digital design with keyboard programming, portamento and several trigger selection options. It's not ideally suited to the Syrinx — one pair of leads has to be disconnected every time a new sequence is to be recorded — but it is quite versatile, and allows the Syrinx to create some earth-shaking bass patterns or lengthy melodies.
The Syrinx could have been an all-time best-seller with a slightly more logical design layout and a few touches like modulation on the touch pad, ADSR retriggering, random modulation and more variable LFO assignment. As it stands, it takes a little getting into, but the special features make this well worth the effort. The combined effects of PWM at two different speeds for chorusing, three filters being modulated in different directions at different speeds, screaming harmonic distortion and a sub-oscillator have to be heard to be believed, and are definitely not suitable for synthesists of a nervous disposition. The Syrinx makes the kind of sounds that make people ask 'how did he do that?', and if there are any more like it on the Synton design boards, Rod Argent's, or somebody, should get them over here fast. Last conclusions? Buy one.
The Syrinx is available from Rod Argent's Keyboards, (Contact Details). Retail price including VAT is £350, or £495 with the CSQ 100 sequencer. Our thanks to Howard Brain and Jeff at Argent's for making a review model available.
Review by Mark Jenkins
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