ALL TOO OFTEN, it seems, musical instrument designers have been happy to take the electronics from inside their keyboards, put them into smaller, keyboardless boxes, and sell them as rack-mount "expander modules". Few people seem to have realised that users of rack-mount units may actually have different requirements from musicians who want a complete, all-in-one instrument. Even musicians who have both keyboards and rack-mounts in their collection may demand different things from them - yet up until very recently, they were most likely to get the same wine in a different bottle.

Now Yamaha, along with several other of the major manufacturers, have seen fit to equip their latest voice module with a few features of its own.

The machine in question is the TX802, essentially a modular version of Yamaha's new-generation six-operator FM synths, the DX7IID and the DX7IIFD. All the new DX7 features are here: fractional level scaling, random pitch, microtonality, aftertouch pitch control, expanded LFO and so on.

Also present - for the sake of convenience and ease of access, if nothing else - are a slot for the new Yamaha standard RAM4 cartridges, and a 2X40-character LCD capable of displaying small bar graphs of levels as well as conventional words-and-numbers data.

But, as I've just intimated, the TX802 goes a bit further than this - and usefully so, too. To start with, there's an expanded memory capable of holding 128 preset sounds and 64 user sounds; you can also squeeze 64 of your own creations - or 63 of your own custom tunings - onto each RAM4 cartridge.

A single cartridge can also hold up to 64 "performance combinations", and herein lies the key to the TX802's versatility, over and above that of its keyboard-equipped brethren. For the new TX is, to quote from popular hi-tech music parlance, eight-voice "multi-timbral".

That means up to eight of its ROM or RAM voices (or "timbres") can be combined together to form a single "performance", accessible through a single program number. You specify the note range of each timbre, which MIDI channel (1-16) it will receive on, and whether the timbre's audio output is sent through the 802's stereo mix out, or through one of eight individual voice outputs.

In the studio, this flexibility of MIDI and audio channel assignment should make the TX802 a tremendously versatile source of voices. Playing FM sounds manually from a MIDI keyboard is something any number of similar Yamaha modules makes possible, but up until now, a complete TX816 system has been necessary for engineers requiring separate MIDI channels for sequencing, and separate audio channels for adding effects.

Putting a load of complex, state-of-the-art electronics in a two-space rack unit can have its disadvantages, of course. Particularly if, like Yamaha, you want to encourage users to get inside those electronics and start doing some serious programming. The less space you have, the fewer knobs, sliders, graphics and displays you can fit into it - and that's normally bad news for the enthusiastic programmer.

In some ways, though, this economy works in the TX802's favour. The front panel is neat and uncluttered, and therefore easier to get to know (though not necessarily understand) than that of the DX7II.

A row of eight switches beneath the LCD are used to turn the module's tone generators on and off (what could be simpler?) and also to select parameters when you're in a programming frame of mind.

Beneath that lies an operation guide which can be pulled out from within the 802's casing at any time. This gives you a rundown of features and how to access them, and is supplemented by three graphic charts (similar to those found on the DX7s) which show level scaling, EG and algorithm formats.

Another set of eight switches is used to select modes (Voice Edit, System Setup and so on), while a numeric keypad serves as the main method of data input, along with separate pairs of increment/decrement and yes/no switches.

There's not really too much to be said about the way the TX802 sounds. If you like the sound of a DX7II, you'll like the sound of this; and if you like the sound of the original DX7, you'll love the sound of this.

The factory presets are arranged in two banks of 64, and while the organ, FX and tuned percussion programs are better rounded than their first-generation FM equivalents (I especially liked "Nu Marimba" and "MalletHorn"). The biggest improvement comes with strings and brass - especially on solo (as opposed to ensemble) voices, which have much more depth and detail of movement than before.

All in all, it's taken Yamaha some while to get around to the multi-timbral way of thinking. But now that they have, they've done it with a vengeance.

I simply can't over-stress just how important individual MIDI and audio channel assignment are in today's studio world - on anything from a dancefloor remix demanding separately-treated oddball percussion noises, to complete instrumental soundtracks requiring a variety of interweaving timbres.

Think about it. When was the last time you heard an FM synth sound on a record that wasn't dramatically treated by outboard processing?

There may be any number of rack-mount modules currently offering "digital clarity". But if I was a keyboard player who spent a lot of his time in a multitrack recording environment, I know which one I'd choose.

Price £1329 including VAT

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