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Synthaxe revisited

update on THE guitar synth

The story so far... Inventors Bill Aitken and Mike Dixon have developed a revolutionary guitar synthesiser. Working with borrowed keyboards and cannibalised computers they have taken their creation from a misty dream to an ungainly, perspex prototype.

Hearing of their efforts, and intrigued by the reported £7,475 price tag, One Two typist, Colbert, visits the SynthAxe workshops in April of 1984, dubious to say the least.

Beneath the perspex he sees more electronics than in a fire sale at Cape Canaveral. He strums an E major, and out comes a grand piano, courtesy of a connected Fairlight. Tugging thoughtfully at his bottom lip, he asks to be let out of the toilet where he's hidden and writes a review, promising to return when there's a production model ready for inspection...

And barring one or two 'last minute adjustments' as they are known in the saloon bar, that's what SynthAxe now have on their hands. When we looked at the SynthAxe in our June issue (first feature and first colour pic, pages 78/79) it was the principle that took us back... a guitar synth based not on temperamental pitch to voltage conversion, but around electronic analysis and recreation of everything a normal six string does. Electrical string to fret contact decides the pitch information, magnetic sensors detect which string has been plucked and further measuring devices calculate string bend, vibrato, dynamics and so on. That's just the system for mimicking ordinary guitar technique. There's also the series of touch sensitive pads and keys that will be to the guitar what the ivories are to a keyboard.

As the SynthAxe moves closer to appearing on the shop shelves, we thought we'd do an update and this time see how the creature plays, and what the designers have done to keep their promises.

As a recap for those who didn't read the earlier report, the SynthAxe is a controller for all MIDI equipped synths, though because of its sophisticated facilities is generally associated with the likes of Fairlights, Emulators, Chromas and T8s. It won't make a sound on its own. The sensors dissect everything you do, break it into digital bits a computer can understand and those are then translated into synthesiser language. It's free of the occasional glitches and hesitations of pitch to voltage conversion, can be made to sustain indefinitely, and will get up to very, very odd tricks.

The pre-production rig is red, not blue as in the mock up. But colour is an easy matter when the casing is GRP (fibreglass to you or me). The interior is still a mass of chips, but now on three main boards, two inside the body and a third running up the inside of the cast aluminium neck.

Thankfully they've perfected their fretting system which on the prototype was a finger shredding cluster of pins. Today each fret is divided into 11 contacts separated from each other by a thin layer of insulation. The divisions are diamond shaped so one contact leans against another, providing a smooth surface on which to bend strings. You can feel a slight friction as you push the strings across the ridges, but not much. The figure 11 represents one contact per string and one contact between each string to help the software sort out what's going on.

As the original review revealed, SynthAxe have abandoned the traditional neck layout. The two octave black, plastic board has 25 equally spaced frets – none of this closer together up the sharp end bit. I still found that the most unsettling part of the transition. Surprisingly the strange angle of the neck is not so awkward to adjust to. Because none of the strings actually makes any sound (they are only there to be 'sensed' and used as a contact) the builders have been able to shift the layout to suit their purpose. There are two sets of strings, one for the left hand, another for the plectrum. Ball ends slot into retainers within the body, you snip the strings to size then slip them into Allen-keyed adjustable blocks either in the body or hidden under that folding plate that acts as a headstock. SynthAxe have allowed 10mm of travel to tension the strings, but say 5mm should be sufficient. It might seem tempting to have very loose strings for an easy action (remember, their pitch doesn't matter) but if you don't watch it, you'll find a sloppy top E will slip off the edge of the neck.

The neck has a chunky, Les Paul thickness and roundness, largely through necessity because it has to contain the fret electronics. The evenly spaced frets leave you with a feeling of 'where am I now' which is compounded by the action – it's virtually the same everywhere on the neck. To make a good contact the string has to be sensed by two frets (those either side of your finger), and that requires a proper action at the 'nut' similar to that at the octave or two octave mark. I doubt you would ever describe the SynthAxe as a 'speedy' guitar – the action is higher than many Japanese six strings sold on their slickness, but the lightly tensioned strings help overcome that. Final models should also have lower frets than this pre-production sample which felt not unlike early high beaded Strats.

This time round, we had a chance to study the magnetic triggering system that works from those short, plucking strings. Each one is connected, via a spring, to a small magnet nestling close to a transducer. As the string is pushed away from its rest position by a plectrum (or fingernail), the pressure moves the magnet back from the sensor. Nothing happens until the string is released to twang back to normal. The magnet springs forward again, and the now activated sensor sends off a trigger to the synth electronics. The harder the twang, the more rapidly the magnet jumps back, the stronger the trigger signal, the louder the eventual output. Dynamic sensitivity, elegantly and simply done.

At this point you may be wondering, why go to such elaborate trouble to operate a synthesiser when a set of black and white keys can do it more easily? If the SyntheAxe's only purpose was to allow guitarists to make identical noises to synth players then Messrs Aitken and Dixon would be well off for raspberries for years to come.

What is vital about this device is its vast potential for new techniques and forms of expression.

When I sat down to the SynthAxe, Bill Aitken assured me that no more than a dozen people in the world had played this sample. They'd all made it sound completely different, and most had come up with fresh methods of playing it even the inventors hadn't envisaged (I'll tell you mine in a minute).

This new horizon hovers around in the black keys in the top right hand corner – six individual tabs, one for each string, two larger, lower pads for the top three and bottom three strings, one curved heel pad that forms the master trigger for all six. They're all dynamic and second touch responsive – and they've got rhythm. One of the shortcomings of pitch to voltage guitar synths is that you cannot easily start and stop the sounds fast enough to produce percussive, rhythmic playing. The SynthAxe is a funk guitarist's dream.

For a start you can use your right thumb to slap out bass notes on tabs of the E or A strings. For added conviction, those strings could be isolated and dropped in pitch by an octave. With certain synths such as the Fairlight and Oberheim Xpander, they could also be given their own sound. Any of the strings can be electronically retuned anywhere in the range, independent of the others.

Next you can crack out the top half of the chords using the treble string pad, or any of the individual keys. For variety, slap the heel of your hand down on the master trigger to punch out a full chord. Dynamic and second touch sensitivity will recreate the thwack and tug of a bass guitar (especially if you're using a sampled bass in the Fairlight), the filter can be brightened for brassy accents, and any sliding of your left hand fingers will be preserved and performed whether it be a glide to the next fret, or a glissando to the last of the 25. Try doing that on a keyboard.

On softer, stringier sounds, the tremolo arm has a warmth and looseness to its vibrato that far outshines a synth's mod wheel. That's because each waggle you make is slightly different from the last and not the repeating product of a low frequency oscillator.

Or try holding a four note chord with the individual keys, then, in turn, pressing each one just a little harder than its neighbour. The second touch effect shifts the volume, brightness or resonance of each string giving the chord a unique undulating feel.

Otherwise (and this one's mine, so remember who did it first) you could abandon the lot and use the thumb and first two fingers of your right hand to batter the master trigger switch on its own. It will machine gun whole chords at a speed not normally associated with plectrums and fingers, and you're still free to make each split second punch as loud or soft as you like.

Don't expect to pick the SynthAxe up and immediately apply your normal six string technique. It's like going back to the first time you tried a guitar. The left hand is moving, the right hand is moving, but because of the new layout and angles, the brain cannot initially bring them together. The SynthAxe will be able to accept and express the practiced dexterity of your hands. It's your brain that has to be retrained.

The pre-production instrument hangs heavy – there's more aluminium to be taken out of the casting, and fibreglass from the body. It should come down in weight by about 30 per cent, but will still be a Les Paul rather than a Tele.

In talking about playability we've missed the extra software and function improvements the makers have made, so it's roundup time.

Below the tabs and the plucking strings are matching rocker switches both with the same function – making the guitar playable with your left hand only so the act of pushing the strings against the frets is enough to trigger the synth. In one direction the switch will latch, in the other it switches to that triggering system momentarily. The result – every hammer on is now perfect and as loud as plucked string.

Next the SynthAxe console which will be sold as a separate unit. It's a programmable library which will remember tunings (master and individual), the status of the accompanying hold, damped and undamped pedals and call up sounds from the attached synth so each can have its own SynthAxe function pattern. There will be 50 memories in all, the console has eight MIDI ports and – neat this – holds within it a map of MIDI behaviour for most of the top synths. Therefore it can talk to a Fairlight, Emulator II, Prophet T8 as would another Fairlight, Emulator II etc, so you're always getting the best of the MIDi potential.

SynthAxe, the inventors are still discovering tricks to pull with SynthAxe, the guitar. For example, there's a capo function that gives any fret a new open tuning but because it's electronic and not physical from a bar pressing against the strings, you're sill free to play below the newly 'marked' fret.

They knew that before, but it occurred to them, well, if you put the capo at the octave and use different sounds either side you could have a bass guitar (or sampled 12 string, or sampled classic) at one end and a six string (sampled Strat, sampled Les Paul through Marshall stack) at the other.

In terms of expression the SynthAxe is orbits ahead of any guitar I've ever encountered. For £7,475 it ought to be stunning – and is.

Synthaxe revisited: £7,475

Also featuring gear in this article

Previous Article in this issue

Westone Thunder Jets

Next article in this issue

Rockschool Club

One Two Testing - Copyright: IPC Magazines Ltd, Northern & Shell Ltd.


One Two Testing - Sep 1984

Gear in this article:

Guitar Synthesizer > Synthaxe > Synthaxe

Review by Paul Colbert

Previous article in this issue:

> Westone Thunder Jets

Next article in this issue:

> Rockschool Club

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