As Yamaha's latest blurb for the DX7 points out, there can hardly be a single professional studio, demo facility or Top 40 hit in the last two years which hasn't been graced by the presence of the amazing FM system. It makes you think, don't it — that a single keyboard could have such dominance in the market, something the Prophet 5 or even the MiniMoog never quite achieved.

What's been lacking have been a few alternatives to the DX7 from the Yamaha camp themselves. The DX9 never seemed economical, despite recent price cuts in the shops, and the massive DX1 was outside the price range of most individual human beings. There are a few more innovations to come in the lower price range, but Yamaha's most spectacular introduction for the Frankfurt Music Fair has been a big budget system, consisting of the TX816 modules and the KX88 Remote Keyboard.

The TX816 was, in fact, launched a year ago as the T8PR, partly intended for use with the massive QX1 sequencer. The 816 consists of eight modules, each representing a 16-note polyphonic DX7. It's amazing how small a module the guts of a DX7 can pack down into — to confuse you even further with some more code numbers, you can get hold of a TX216 which has two modules and a power supply for £1899, and further modules (labelled TF1) for £449 each.

Assuming we have a complete TX816 system (never mind those paupers who've only got £1899 to spend), what can we do with it? Well, as mentioned, you can address each module individually from a QX1 or another sequencer such as Roland's MSQ700 or Yamaha's new £499 QX7. Each module is completely polyphonic and responds to velocity and aftertouch information if it's programmed in, but as far as we can see isn't self-programming — you need a DX7 or CX5 computer to alter the sounds. Dave Bristow's major demo piece for the QX1 and modular system consists of most of Ravel's Bolero, and it's fair to say that the only thing missing is Bo Derek stripping off. The authenticity and power of the sounds can be stunning — encompassing all the DX7's subtlety and brute force, from orchestral sounds to chimes, cutting melody lines and percussive effects.

So one application of the TX816 is multitrack composition, tied into a MIDI drum machine such as the Yamaha RX11, RX15 or Sequential Circuits Drumtraks. You can play an entire TX816 rack from a DX7 or other MIDI keyboard (accusations of overkill to Yamaha rather than ourselves please), but as usual Yamaha are one step ahead of us and have come up with something better.

As we mentioned, the DX1 never got the stranglehold on the top-end market that Yamaha may have wished. The size of a sideboard and reminiscent in hernia capacity of the much-loved CS80, it skipped by the modern trend for compact and sleekly-styled keyboards as well, and has now been partially superceded by the DX5 at £2999. To offer an alternative to the DX1's high-quality wooden weighted keyboard, and to keep the pianistic fraternity happy, Yamaha have introduced the KX88, a voiceless Remote Keyboard or what Roland might call a Mother Keyboard.

Introducing Mr Dave

Yamaha previewed their new launches in Hamburg with demos by the aforementioned Bristow (or "Mr Dave" as the Japanese contingent fondly refer to him). To say that his KX88/TX816 demo was impressive would be to describe the second world war as a minor skirmish. It were reet grand, in fact.

Mr Dave started off by demonstrating the complex synthesis capacities of the TX816 setup. With one module producing a damp clunk, one producing a high metallic chime, one on low bass with long release and so on, you can come up with the most amazingly responsive acoustic piano sound. Overkill, yes (particularly when you look at a cost of around £5,000 to do it) but since Mr Dave has spent all his time inventing the sound and put it on a preset for you, you may as well use the thing.

The following demos used complex keyboard splits together with the performance effects assignment capacities of the KX88, of which more later. The important thing to keep in mind is that the KX88's own keyboard split capacities are rather limited — just one programmable split point with different MIDI channels addressed on either side of it. The TX816's capacities are rather more impressive though — call up a note display on the tiny LED of each module and you can then step along to choose a keyboard start and end point for each module individually, with musical notation of the keys responded to. In other words, if you want module one which is programmed with a choir sound to only respond to one particular octave-and-a-half of keys, you step its display along to C4 for the start point, and F#5 (say) for the end point. Where you play on the controlling keyboard then decides what sounds or mixtures of sounds you call up.

But the KX88 has more than just a keyboard split to offer. Firstly, it does have a very smoochy, wooden weighted key action which gives you very precise velocity and after-touch control. Then there are three assignment modes — single, dual (or layered) and the split mode we discussed. Then four programmable top-panel sliders which can be assigned to any performance parameter as part of a patch. These can even include transmission of data in the System Exclusive mode, which means that you can alter FM ratios and other parameters to simulate filter effects or things a little more strange and bizarre.

Total control

In addition to the sliders you have two conventional performance wheels, which would normally be used for pitch bend and modulation depth, and five momentary switches. There are also two toggle (changeover) switches, plus two foot pedal inputs, plus two footswitch inputs, plus a breath controller input.

No, don't ask me what all these do. They can do whatever you like — volume on a foot pedal or a slider, patch shift on a footswitch, FM ratio on a slider, portamento time on a footpedal. It's entirely up to the individual performer to decide how complex a patch he can use, how well he can co-ordinate his limbs and organs to alter it live, and how much he wants to give the impression of an octopus flailing about in a quest for new noises.

The potential effects are tremendous. How about an orchestra with a solo violin responding to the modulation wheel, a full string section fading in with a foot pedal, a brass section coming in with aftertouch, and a female choir on a slider? How about a string bass from the bottom octave-and-a-half of the keyboard with a Clavinet on the top alternating with a Hammond organ with overdrive on the touch response? How about a devilishly effective imitation of a sampled orchestral crash complete with brass, timpani, strings and basses on a single key at the bottom of the keyboard? And if you want a ride cymbal on every bass beat, you can have one, courtesy of whichever TX816 module you happen to have spare.

Mr Dave describes the KX88/TX816 setup as being "the top of the FM range — for serious musicians" and the KX88 as being entirely suitable for trained pianists. Certainly it feels good, and with seven and a half octave of keys it presents no limitations in range. If you want to play classical piano pieces you'll certainly appreciate that range, but it's also there for those who want to take full advantage of the TX816's key assignment capabilities. For instance, you may want three octaves of strings and three octaves for a lead line sound, in which case a plastic four or five octave keyboard isn't going to do you any good even if you split it until you're blue in the face.

For live work, the KX88 could be incredible. Its patches work in two modes — in Two Bank mode you have 1-32 x two channels of patches, and in Eight Bank Mode you have 1-128 x two channels of patches. Enough for any live performer. There's an LED display rather than the dimmer LCD display of the DX7 to tell you the patch number, so no visibility problems on stage, and the only anticipated problem is deciding exactly how you want to patch all the performance options to suit your own capabilities.

The sounds of the KX88/TX816 combinations are nothing short of frightening. It's going to be a biggie, inevitably mainly for studios, but it'll be fascinating to see a few on the road in the coming months. You're unlikely to get a demo as stunning as Mr Dave's in your local music shop, but there's no way to imagine the possible sounds unless you go and check them out in person.

Yamaha KX88 & TX816 — RRP £1339 & £3999 approx