OPINION

Keyboard players have been fantasising over a new DX7 for so long, they've almost starting writing songs about it. When most manufacturers overhaul their models every 12 months, it's taken Yamaha four years to decide they had something new to add to what is now the most famous synthesiser in the history of music.

However, as demonstrator David Bristow explained at Yamaha's UK launch, it is still a DX7 - not a 'Super' or 'Expanded' 7 but, the instrument Yamaha would have released in 1983 if they'd had the knowledge of 1987.

There are still six operators, the same preset 32 algorithms, and it continues to be 18 note polyphonic. Improvements have come from the test bed of other Yamaha synthesisers. The keyboard can be split, and sounds layered, as on the DX21 and DX5, and vast emphasis has been placed on performance functions. On the original 7 each sound could store its own choice of algorithms, keyboard scaling, etc - all the purple coloured stuff. The brown functions, such as modulation wheel range and portamento, could only be set once, for the keyboard as a whole, and every sound got the same deal. That distinction disappears on the II as each sound can have its unique performance characteristics programmed as part of its identity.

It's in these performance areas that Yamaha's R&D men have had the greatest fun, and developed details you won't find on any other DX synth. But before that... first impressions when the cardboard box lies shredded over the carpet.

The keyboard itself is far better — firmer, more resilient and responsive. Out go the membrane switches, replaced by coldly numbered buttons with only a slight mechanical movement, but a satisfying click so you know contact has been made. The LCD screen is now backlit and greatly expanded to 80 characters in two lines, partnered by two larger LED displays for the important numbers. The cosmetics have been tweaked. It's darker, slightly chunkier, the end cheeks have gone and the back has two supports so the synth can be stood on its edge. I felt the position of the sockets was a backwards step. On the original 7 they were close to the upper lip of the back panel and easy to find from round the front of the keyboard. The II has them half way down the back panel, and I spent extra time stabbing about with the jack plug to locate them.

The cartridge slot is now closer to the data slider, and it's a larger, newly formatted cartridge, by the way. But the mark II includes an adapter so you can still use favourite RAM packs from your old DX7. The alternative £1899 7 II F has a floppy disc drive built into the side if the 64 internal and 64 cartridge voices are not enough at one go.

Finally, before we start punching buttons, there is one more overall change Yamaha have made. The majority of a DX7's sound creation goes on in the digital domain, that is, all the waveforms, envelopes, etc are calculated to arrive at the set of numbers which represent the sound you eventually hear. A code, if you like, which is converted to an audio signal by the DAC (Digital to Analogue Converter). Yamaha have shoved two extra 'bits' of processing power on the II's DAC line up, resulting in cleaner and even brighter sounds as there's more headroom for the upper frequencies. I found the difference was subtle, but it is there.

Anyway, performance stuff. Firstly it's stereo. The possible configurations start as simply as having a different output for each half of a layered sound. At the extreme end, the II's pan department has its own envelope generator so you can program a complex stereo journey for any sound.

Portamento now borrows from an old analogue synth idea - while you play staccato, there's no glide, but hold down two keys at once, and the Portamento turns on. Extra expression, simply from your keyboard technique.

In place of the old mono/poly format of the original you can now stack oscillators in unison mode. The difference on bass sounds in particular is little short of staggering - not just low, but far fatter and 'analogy' than the original could ever sound.

There's a trick called Forced Damping, especially useful on layered patches where the polyphony drops to 8 notes. To ensure you get a complete envelope for each new note played, and that the II doesn't pick up from the sustained portion of the one that's gone before, it will momentarily force the volume down to zero so the envelope can start afresh.

Much fine detail has gone into methods of modulation, and I wonder how fiercely Yamaha were stung by early criticisms of the DX7 as a cold and thin sounding device. Certainly the amount of 'humanising' now possible would be tough to equal on any other keyboard. Take the LFO. Suppose it's modulating the pitch on a steady sine wave. Press one key and it begins its journey on the crest of the wave, any key pressed a split second later may begin half way down the slope, and the one after that find itself in the trough. They are all, however, moving up and down in pitch exactly in sync because they're travelling the same wave. That would be like asking an orchestra's string section to begin vibrato at precisely the same instant, in the same place, at the same speed. But give each new note its own sine wave, and have everyone begin on a peak, regardless of when the note is triggered, and you get closer to the real thing. The pitch of some notes are moving downwards, while others are moving up ... like real ensemble vibrato.

Further in the same direction, the II has a Random pitch shift that (in small doses) detunes by differing degrees instant to instant.

And weirder still, a Micro Tuning function allows each of the keys to be individually tuned, just as if you were a piano tuner fiddling with every string. Alternative tunings or temperaments as they're known, can be stored on a RAM pack, and there are 11 pre-sets on board, including 1/4 and 1/8th tones. This is not the place to expound on temperaments. Suffice to say they're there, along with dozens of other additional items of programming finesse.

That's the deep stuff. On the surface there are more obvious inclusions. Two sliders act as programmable, real-time controls. Any element of a patch — algorithm, coarse tuning, you name it — can be assigned to one of these sliders to be changed as you're playing without having to dive into edit mode. Two foot pedals can do the same job.

But I was just happier to see easier programming of the features common to the original 7. Each operator now has its own select and on/off button so there's no tedious stepping through the pecking order to reach the one you want. And the permanently confusing level and rate figures for the envelope generators are now displayed, side by side, in one scan of the LCD. Now they make sense.

DECISION

There are scores of small details unmentioned here because of space. The important thing is, they're there to be discovered as your programming prowess grows. Yamaha haven't simply bolted on extra sets of oscillators, but have gone deep into the software and improved from the ground up.

I am surprised to find the DX7II is not multi-timbral. Since Yamaha have done this so successfully with the far cheaper FB01 - up to eight different mono sounds at once from a MIDI sequencer - it's the only major disappointment not to find such a facility on the far more sophisticated 7II.

Other than that, it's virtually impossible to fault. The power for expression is magnificent, the degree of individuality it allows you is stunning, the basic sound has improved, the facilities are greater and easier to comprehend, the resulting noises more versatile than ever.

Yet at Dave Bristow's demonstration, the most impressive sound I heard was a steel strung acoustic guitar patch which not only had the twanged note, but the metallic squeak as your fingers slid up the strings. Sitting down with the DX7II when it arrived, I studied the patch and realised there was really little to it that couldn't be done on the original DX7. It was just clever FM programming, which goes to show that Yamaha did all the hard work five years ago.