The Synergy is a fully digital polyphonic synthesiser that in many ways represents the state of the art at the present time. Designed by Digital Keyboards Incorporated in the U.S.A., it offers the musician a wide range of expression through its touch-sensitive 74-note keyboard and its analogue style controls.

Its sleek black 'ivory' finish package is complete in itself, holding a computer system with memory and the digital equivalent of 32 voltage controlled oscillators, which provide sounds for 24 preset and 24 interchangeable cartridge voices. The system layout makes it a versatile and portable 48 preset performance instrument and the all too common complaint of 'synths lacking expression' is easily overcome by its dynamic keyboard control that can actually increase the expressive technique of an acoustic pianist. It was also one of the first instruments to set the trend for sequencers to be included on polyphonics - the Synergy has a 4-track sequencer that can utilise the different voices available in a variety of ways.

Layout and Voices

All the synth controls are situated on the sloping front panel above the keyboard, with vertical white legends dividing them into the following groups, from left to right: Volume, Pitch bend, Sequencer, Portamento, Vibrato, Amplitude and Timbre, Program settings, Transpose, Voice Assign, Restore, Voices, Channel Assign, Tuning and Cartridge (with the cartridge socket at the far right). The switches are all light touch momentary types with an LED indicator built in (except the Channel Assign). Incidentally, an internal electric fan cools the microchips during operation.

Apart from the 4-way joystick, all the controls are rotary types. 24 individual voices are stored in the Synergy and are selected from the two horizontal rows of 12 switches. The voices can be used in either 'Single Voice' mode using one voice on the keyboard at a time, or 'Multi-Voice' mode, where up to 4 voices can be used together. A voice is selected by pressing one of the 24 switches and its red LED indicator will then remain on unless you are playing on the keyboard. Pressing the switch again turns off the voice (and LED). Most of the switches work in this touch on - touch off way.

On power-up of the instrument, the Single Voice mode is selected and consequently, if you choose another preset, the first voice will be turned off automatically. Because the Synergy is under the control of a micro, it is possible to offer performance variations through its switching arrangements that would be uneconomic and complex in normal analogue synthesisers. For example, pressing a new voice switch, while still holding a chord on the keyboard, allows the original preset to continue sounding to the end of its release. The new voice then takes over. On the other hand, if you select a new voice after you've released keys playing the original voice, any note still sounding will be cut off immediately and the new voice will take over on the next new key(s).

Since 32 oscillators are available, it may be assumed that up to 32 notes can be played at once in single voice mode. Actually, this is not the case, as some voices need more than one oscillator to make the sound required. Organ, for example, is touch sensitive programmed to increase its 'stops' to full organ, implying the use of 16', 8', 5¼', 4' etc. oscillator pitches.

But generally, there's more than enough to go around, unless the sequencer is using voices as well as you playing several others at the same time. The foot switches can also have you running out of oscillators quickly as well.

One of the main features of the Synergy is its ability to play up to 4 voices at once (each polyphonically). By pressing the Save switch once, the Multi-Voice mode is selected. Up to four voices can be chosen and their LEDs will light up. Any other voice switches pressed will be ignored and, incidentally, modulation effects like vibrato will only occur on the last voice selected.

Performance Controls

A dual pedal is provided with the instrument, with the left-hand pedal acting like a middle pedal on a grand piano and sustaining keys held at the time of switching, but not further keys played after. This is an interesting musical aid that, for example, could sustain a chord while staccato sounds are played over it. The right hand pedal gives the familiar sustain on every note played when depressed.

A Tuning knob effects all voices on the keyboard and sequencer, and will alter pitch ±1 semitone from A440 standard pitch. Deviation from the standard is shown by the tuning LED indicator lighting up.

It is important to note that, in common with other digital synths using analogue type controls (e.g. PPG Wave II), knob settings are not actually changed until the knob has been turned fully left or right and to the position of the current setting. The LED above the knob then turns on to show the control is active. Often, many of the knobs will automatically be de-activated during program and voice changes where it is more logical for the settings to be initially the programmed ones.

The Joystick enables two modulation effects to be achieved simultaneously if desired, with horizontal movement controlling Pitch Bend and vertical controlling Vibrato Depth. The actual pitch bend (pitch deviation) made by a left and right movement of the joystick can be easily set to any interval up to a perfect 5th up or down. This is done in conjunction with the Restore switch (for a 5th) and the Sustain foot pedal and Set switch for any other interval. On power-up the bend is set to ± whole tone.

Voice Controls

Polyphonic portamento is always an impressive effect and the Synergy has some interesting possibilities. Here, the computer system scores again, as it keeps track of complicated portamentos. Pressing the Portamento Quantisation switch once turns the effect on or off. The various results are produced by sustaining left and right hands at slide start and finish points in conjunction with the Sustain pedal. These include portamento crossing through a chord, crossing another portamento, expanding and contracting chords, and (apparent) random slides around the keyboard. The portamento rate can be changed from a very slow movement to instantaneous jump. Incidentally, movement time for any portamento interval is always the same for the particular rate set.

The Quantisation switch can be pressed again (and its LED flashes slowly) for retaining the initial envelope on the final finish note of the portamento. One more press, to complete the cycle, (with the LED flashing quickly) gives semitone glissandos and new triggering on each note.

Occasionally it's possible to reach a point in tailoring a preset voice with the various controls when you decide to start again and a Restore switch is provided to do this. The original preset or cartridge preset cannot be destroyed and even restoring can only be done by following the correct sequence: after pressing Restore switch, press either a single voice switch, or the Cartridge switch (for restoring all the voices), or the same switch for clearing the entire Synergy to its original factory state.

Vibrato is a well known effect that can be added to a voice using the Vibrato Depth knob. It usefully provides increasing pitch change to the right of centre and interesting random pitch jumps in an anticlockwise direction, (the random effect is not available from the joystick). Vibrato Rate can also be changed with an adjustable Delay. In order to achieve the precise sound for a preset, the Synergy puts either periodic (i.e. all notes with synchronised vibrato, for vibraphone) or aperiodic (random sounding changes suitable for flute).

Transposition can be done on the last voice selected and it's easily set by selecting a note below middle C - the interval formed by this note and the second C above the lowest note sets the transposition interval up (12 semitones) or down (20 semitones).

Because the Synergy has left and right outputs available, each with their own volume control, it is possible to independently assign voices to them.

The Channel Assign switch sets the 4 options shown by the state of its 2 built-in LEDs and will set the last selected voice to centre, left, right or alternating right and left on successive notes. Needless to say, the latter is most effective with a single voice in use and since each voice can be assigned differently, some superb stereo mixes can be obtained in Multi-Voice mode. Many voices already have some kind of key control present but you can override this.

The keyboard is one of the most dramatic in its control of amplitude and timbre. Sounds are changed by striking the keys faster or slower. The degree of control you have over volume is set by the Amplitude Sensitivity knob and an Amplitude Centre knob will emphasise a part of the dynamic range.

The Timbre (or tone) of various voices can also be changed. Instead of a smooth tonal change, some voices actually jump from one timbre to another which lets you highlight individual notes, (sounding as if they come from another instrument). A Timbre Sensitivity control selects 'smooth' or 'jump' transitions of tone and Timbre Centre shifts the emphasis from one timbre to the other.

Voice Assignments

There are 7 different ways in which voices can be played in Multi-Voice mode. Normally, voices will sound in unison with each other (polyphonically). The other options are 'Rolling', where each new key is assigned to a new voice - a fairly frantic effect; 'First Available' is similar to rolling but holds the new key notes to the same voice, e.g. holding a 3-note chord in the left allows a single note melody to sound on the same voice in the right hand; 'Key Split' works on 2 voices only and puts them in selectable portions of the lower and upper keyboard by means of the Set key and a quick tap of the chosen split note. Unlike other instruments, this one note will not sound during your performance. 'Float Split' is another clever assignment from the Crumar GDS Digital Synthesiser, it lets the keyboard follow the player's hands and keeps the voices tracking up and down. Provided each hand spread is within a tenth, the micro will nearly always get it right! 'Compound Split' offers left hand single voice with either Rolling or First Available in the right. Finally, transposition used in Float Split mode can even have your hands playing the same pitch ranges in different parts of the keyboard!

Programmes

Eight programmes can be stored (and kept indefinitely by the internal battery back-up) - four for the internal voices and four for the cartridge voices. The Synergy has at least 3 cartridges available to date as extra voice sounds. 24 more voices are supplied on each cartridge and that should be more than enough for most musicians (with the 24 internal voices as well). One advantage of the cartridge I heard was the addition of percussive type sounds, but these cartridges do rely on GDS owners to submit new material and after trying the first cartridge, further voices tended to sound somewhat similar. All the voice controls will change the cartridge sounds exactly like the other internal presets, but the sequencer only works properly on cartridge or preset.

Sequencer

It is basically capable of recording 4 tracks of music in a polyphonic (more than one note per track) and polytimbral (more than one voice per track) to a total of approximately 1,860 notes. This will enable complete pieces of varying lengths to be recorded - a logical approach has to be made here for best results with some calculating of numbers of voices, notes per voice, and total tracks to ensure you don't run out of events (and oscillators)!

One big drawback from the performance point of view is that the sequence is lost when power is turned off - but of course, it's not too difficult to pre-record on stage beforehand.

Anything played on the keyboard can be recorded by the Sequencer and it will accommodate any combination of voices, voice assignment modes, portamento, pitch bend, modulation, joystick and footswitch control as well.

The sequencer controls set Tracks 1 to 4, Record, On/Off and variable speed playback. Once a track is recorded, you can play the keyboard along with the sequence in another voice if you wish. Individual tracks can be erased and an LED starts to flash progressively quicker as your memory space runs out. Each of the 1860 digital events is in fact not just recording a key note, but includes name of key, voice used, key velocity and key duration (sustain time). Initial rests can be 'forced' by moving say, the joystick, and repeats can be specified for single track or whole sequence. Playback speed can be adjusted from its LED indicator to be exactly twice or four times normal speed. Transposition can also be done on the whole sequence as it plays by selecting notes below middle C on the keyboard in real time. Editing is restricted to re-recording a whole track to get your piece right.

Various possibilities exist in playback of tracks separately or together, stopping or starting, using one track to control other tracks and re-orchestrating. Lastly, there is an 'Even' switch which effectively tidies up chords and notes, pulling them to the nearest main pulses in the recorded bar.

In conclusion, it simply remains to say that it is hard to fault this instrument, provided you like its wide range of presets available, and its comprehensive manual contains all the instructions you will need. Priced at under £3,000, it represents good value considering its high technology and will offer many musicians the kind of keyboard and analogue control they've been looking for in a digital instrument - with the bonus of a sophisticated sequencer!

The Synergy is available in the U.K. from Syco Systems Ltd., (Contact Details).