Eight preset, eight memory programmable four-note poly
Something of a "design by committee" approach to this one, which seems to contain bits of half a dozen synths. The SX400 is a four note poly... or a two note poly... or a one note monophonic synth... has eight preset sounds, plus eight memory spaces and swarms with sliders, tuning controls, second touch gadgets - and so on.
And it's bulky, probably a lot bigger than it needs to be. The poly synth controls are nothing out of the ordinary. It has the standard assortment of triangular, sawtooth, square and pulse width waveforms, two separate ADSR envelope generators for the filter and the VCA (affording greater control than one ADSR for both sections) and a filter.
The modulation LFO is busy as it has ramp, sawtooth, square and triangular waveforms though no sample and hold.
The extras include a chorus ensemble unit (distressingly poor as it's both noisy and lumpy) and a hold facility to sustain a note or a chord indefinitely.
Programming in sounds is likewise standard — hit the red record button and the memory position where you want it to go and the settings are locked in. There are eight memory buttons on the front of the SX400 and one extra switch that lets them swap between calling up the eight, factory-set programmes which can't be changed, and the eight that you can punch in yourself.
Editing programmed sounds is done by the old fashioned way of hitting an edit button, then changing the controls. State of the art synths are able to detect the controls being moved and the interior computer deduces that you want to make an edit without you having to hit a special control for it.
An acne of controls sit in the left hand corner, and these are for tuning. In the quad mode the SX400 acts as a polyphonic four note synth. There's only one oscillator per note, so it sounds thin and weedy. In duo there are two per note, on solo there are four when it's at its fattest and on mono you're back to one note, one oscillator.
Once you're off the quad mode it's possible to set all four oscillators at different footages and that's not bad. It's then in your power to hit one key and spread the sound over four octaves.
Like the Teisco 60P, the SX400 has second touch, so that pushing harder on the keyboard will switch in effects like vibrato, wah wah, pitch bend up or down and so on. It's less successful here, maybe because the keyboard is an extra octave longer and the switching doesn't work as well. You can find yourself bringing in a disastrous special effect in the middle of a quiet passage because the pressure needed is frequently unpredictable.
Unlike the Teisco 60P, the SX400 carries a separate modulation bar at the left-hand side of the keys. It's very like the Roland system — an upright pillar that swings from side to side. Unfortunately it only reproduces what the second touch is already doing, so you can't have, say, vibrato on the bar and pitch bend on the keyboard.
It DOES have polyphonic portamento which isn't always easy to include if you're trying to keep the price down. It's an awesome effect as the notes from one chord glide independently into position on the next. What the SX400 lacks is an arpeggiator, and this is now almost compulsory equipment on the new, lower-priced polyphonics reaching the market.
Neither, unfortunately, does the SX400 have a particularly good sound. The filter is very weak, no real sharpness or variation to it and the envelope generators lack any punch. The oscillators themselves are flimsy in their tone, not especially rich and the only way I found of fattening up the 400 was to set the pulse width modulation operating, either controlled by a slow running LFO or by one of the envelope generators.
This is always a good sound because it can add movement and activity to the notes you're playing. They start off spikey, then fatten out as the ADSR takes the oscillators from skinny square waves to fat ones.
The SX400's trombone and trumpet were okay and the sitar had a spine-tingling quality, but the rest of the presets were plain and boring. The SX400 in for review was misbehaving around the programming section — each time I loaded a sound into position one it would also find its way into position five — very annoying if you'd previously preserved a favourite of yours in number five.
On the back were individual fine tune controls for the oscillators (there was no auto tune on the SX400 and they did tend to drift), CV and Gate sockets, and a signal out with switchable levels.
The blue/grey colour scheme is attractive, but the SX400 is just too large to carry around easily under one arm. It does seem to be sturdily built, however. All the sliders were well fixed and the keyboard wasn't as loose or clacky as the 60P monophonic made by the same firm.
The greatest shock about the SX400 was the price — far, far too high considering the likes of the Korg Polysix with many more facilities and programming abilities for about £400 less. There are shops discounting the SX400 to considerably below £1,000, but even then I have reservations. There are certainly better polysynths on the market, and frequently for less money.