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Yamaha CX5 Computer

Preview of a micro

I motored up to Bedfordshire in early March to see the only Yamaha CX5 in the country at that time, at the residence of Yamaha's FM expert, Dave Bristow. Dave is not your average keyboard demonstrator, however, for he will say things like, "It's a joke... it makes me really cross, quite unforgivable," when describing the lamentable "rhythm section" facility included in the basic CX5.

And the CX5 is no ordinary musical instrument. It is in fact a computer. A new type of computer called MSX, standing for MicroSoft-eXtended. This MSX is an improved version of Microsoft, which many existing computers understand, but also, crucially, is the standard chosen by the most powerful Japanese electronics manufacturers for their coming ranges of computers (already on sale in Japan).

By the time the Yamaha CX5 comes out towards the end of 1984, there'll already be some MSX computers on the market – the Sony Hitbit or a Spectravideo machine may well be the first. And they'll soon be in the company of Pioneer, Sharp, JVC, Mitsubishi, Sanyo, Canon and many others, which means that MSX software, the stuff that actually makes the computers do specific jobs, will become quickly and widely available. But that's all strictly computer talk.

The Yamaha CX5 will be unique when it does appear, because it is the only MSX computer to include FM synthesis as a supplied add-on. No-one else will have this because it was invented by Yamaha for their wondrous DX synthesiser (one of the One Two Instruments of 1983 – see January 1984 issue), and they own the patent, which runs for at least another couple of years. Not one of the previously mentioned Japanese heavyweights will give you computer-controlled FM synthesis.

Some physical details of the CX5 first: what you'll get for the projected £559 retail price is a CX5 computer, an FM tone generation unit, and a number of keyboard options. You can have a standard 3½-octave C-C "mini" keyboard as pictured hereabouts, or an optional full-size keyboard instead. Or you can have a MIDI interface box to allow you to plug in and use your own MIDI keyboard. Which should cover most requirements.

So you've got yourself an MSX 32k computer which, with the appropriate software, will do all the usual things like word processing, killing aliens and telling you how much is in the Swiss deposit account. Thanks to the FM unit you also get a 48-preset FM synth too, and with Yamaha-written music software you'll be able to display and edit/create voices, "look" at what's in your DX7, and write eight-part music compositions using virtually standard music notation. You may well be astounded.

All you'll need to play live music straight away is a TV, preferably colour, to display the information, and a stereo system or instrument amp to play the sound (though you could just use the TV speaker if you really wanted to). A data cassette recorder, for storing stuff, is a necessity too – allow another £40 or so.

Dave Bristow ran through the procedures with me, but not without first reminding me that this is a musical instrument. "It's more like being sat at a piano than at a Synclavier," he assured me. "The feedback you get from it is what you put in, your own creativity is thrown back at you. There ought to be a display in it that says: RIGHT, SO YOU KNOW HOW TO WORK ME AS A PROGRAM. SO WHAT? WHAT CAN YOU DO?"

What you do is plug the system in to your TV monitor and get straight into the synthesiser part of the computer by typing "CALL MUSIC" on the typewriter keyboard. This command is the key that opens the musical possibilities of the CX5: And revealed to you is what resembles a visual DX9-like preset FM synth, although different chips are used in the CX5's FM module and the DX9, so the sounds are not directly comparable. There are eight algorithms (and all the other unfathomable FM business), it's eight-note polyphonic, there's room for 96 voices (48 preset and ever-present, 48 programmable via extra software), a versatile split keyboard facility (variable split point, any of the 96 voices either side), a real-time poly sequencer with room for about eight minutes maximum doodling, and the previously mentioned joke of a "rhythm section" (forget it).

The 48 preset sounds are a strange bunch: some fine and liable to heavy use (the quartet-ish strings and throaty brass, for example) and some which will never be used at all (the so-called "cymbal" for example – even worse than that of the Drumatix, which is going some).

So Yamaha still haven't shaken off the CS80 Unusable Preset Syndrome, with the CX5's presets seemingly chosen without consultation between Yamaha's Computer and Keyboard divisions. Not to worry overmuch, though: without the extra cost of a software cartridge or a RAM pack, you'll probably be able to buy cassettes with extra voices stored on them which have been programmed by musicians ("from me, if not from Yamaha," says Dave Bristow) which you can load into the 48 "empty spaces" after the 48 presets, via your data cassette recorder. A mini-industry supplying cassettes of, say, 200 voices could well spring up, and not just in Bedfordshire.

To go anywhere really creative with the CX5, though, you'd really have to invest in some software cartridges. These cartridges come in boxes exactly the same size as standard cassette cases (handy for existing storage shelves) and plug straight into a slot on the top right of the CX5 computer.

Just what you'll pay for the software cartridges is not certain as I write this – simple games programs for MSX may well go for about £10 or £12. Music software for MSX goes for the equivalent of about 20 quid in Japan, so taking competition, comparable software, and mark-ups into consideration, a street-price of anything between £25 and £40 seems likely. We'll see.

The first three music software cartridges written specifically by Yamaha for the CX5 computer will be the Voicing Program, the DX7 Voicing Program, and the Music Composition Program, which allow you to edit existing and create new voices, to display and alter information from your DX7, and to "compose" eight-part sequences. That's putting it simply.


You can display the parameters of the preset voices, a page per voice on the screen, and alter these, or start from scratch on your own voices. Aids to programming are varied, and include the facility to put the original sound on one side of the split keyboard and your edit on the other, for direct comparison, or the use of a temporary store called a Sound Buffer in a similar way.

In this way you can make up sounds (and save them in the 48 spaces beyond the presets or, of course, on to a cassette) either to be played as a "live" synth, or for specific purposes for use in the Music Composition program, where you may need a very precise sound for your particular piece (Bristow here demonstrates a convincing ticking-clock-in-a-deserted-mansion sound for the rhythmic base of one of his excursions).

On each page, for each voice, either from the store or starting from scratch, is displayed all the FM parameters: the linkage and state of the operators, plus overall levels of output, volume adjustment, rate scaling, detuning and so on. You can also usefully swap around the order of voices in your store, or "directory" as it's called.

"If this was a synthesiser," marvels Dave, "laid out as a synthesiser with all the buttons there for all the things you can see at various times on the screen, it would look so impressive. And the sounds would be impressive too. People would think, oh, £3000, £4000... quite incredible."

There are credible limitations. FM has a subtle but decidedly resident hiss somewhere down the bottom end – carrier noise – which you can get used to. And there are limitations to do with fixed frequencies, as Dave admits. There's also rather a lack of analogue twang to FM – and there's the large hurdle of coming to terms with the actual construction of the sounds and the parameters used, which will be totally meaningless to anyone other than the DX owners amongst us (and probably to many of them, too, who merely Do The Preset).

On the other hand there's a lush presence to FM that's very appealing. The CX5's way of displaying the parameters of FM so that you can see what you're doing made me at least begin to grasp more of what's actually going on, as opposed to all my previous embarrassed fumblings with the occasional DX. With the CX5 I could see myself coming to terms with what Bristow will happily call the most important advance in synthesis since the Minimoog. I found myself nodding.


Dave's warming up now, so we'll let him continue for a bit. "When you think of the cost of this system, if you've got a DX7 already then that's probably reason enough to buy a CX5 and a DX7 Voicing Program, without the fact that it's a computer, without the fact that it's got a synthesiser in it, but just as an aid to programming, to see your DX7, and for back-up storage of voices."

So indeed you can "look", via the TV monitor, at the data already in your DX7, change the algorithms, change all the parameters of each operator, the function controls, and so on. Having swapped around to your heart's content on the computer, you then MIDI-transfer the new data to the DX7. Or you can change your DX7's settings in the normal way and have the added visual bonus of a display of what you're up to – although this comes into the firing line of One Two's special Question For Synthesiser Computer Add-ons: "What does it do that the synth doesn't already do?" Answer (almost invariably): "Nothing." In this case that's slightly unfair, though, as it's only one of many possibilities.

With the DX7 Voicing Program, DX7 owners would save themselves the cost of RAM packs (± £50), and be able to store new voices on to cassette via the computer, 48 at a time (not just 32). They'd also need £550+, of course, and an unfailing belief in Yamaha world domination.


When I first saw this bit demonstrated by Dave at the Frankfurt trade show in February, I was impressed, but somewhat put off by the ear-numbing volume and blatant distortion thrown at me by the boys from Berlin responsible for setting up the sound system. I guessed – correctly, it seems – that the CX wasn't to blame.

Turn on with this program in and up comes a stave in two lines, one above the other, though to be considered as one continuing "part", on to which you can write your piece in any of the voices you care to call from preset, programmed or cassette store. This is the program where you have to start using that old-fashioned medium of pencil and paper. Despite the high-tech on display there's no way of calling up a list of any of your available voices at this point (even the no-software presets). So you have to have prepared a list. A pencil and paper's also handy for keeping a note of the parts as they accumulate.

Notes are entered on to the stave in a variety of ways: by moving a cursor into the required note position on the stave and selecting a note "value" – crotchet, minim, etc – from the row displayed along the bottom of the screen; by a combination of typewriter keyboard (for valve) and music keyboard (for pitch); or by the typewriter keyboard alone (for which function some overlays may be made available, making a mini music keyboard out of some of the keys and labelling specific functions of others). You can also bung on repeat bars, time signatures and so on – if you select nothing, you automatically get an unchallenging 4/4, 120 crotchets a minute, and an old-fashioned electric piano voice. Perfect for pop music, in fact.

Eight parts shall you write, and eight parts shall you hear back. You can get polyphony going by writing "across" the bars with a special display of italicised notes onto what you define as the leading part. Perhaps most effectively of all, you can add all manner of musical expression to your line once it's written in – pianissimo, fortissimo, accelerando, ritardando, crescendo, diminuendo, and all those things hazily remembered from school music lessons. This manages to bring tired old do-ra-mes into some semblance of life.

So, you've got to have a musical knowledge, or at least have read up a Grade One theory book to get you going. It's probably better than having to learn a number code, MC4-style, but it is going to put some people off this highly musical program. If you send this eight-part composition via MIDI to your own MIDI'd polyphonic synth, it'll play the composition on whatever single sound is selected. If you can afford to link up several MIDI'd synths, then you can control them from one or several parts of the eight. But what you don't get on the CX5, regrettably, is eight separate outs. So relative levels have to be set by expression signs, and eventual eq-ing can only be applied to the whole composition (albeit in stereo). Shame.

There's about 8400 steps available, which seems more than enough – remember, a repeat bar sign, for one repeat or one hundred repeats, counts as only one step.

And that's about your lot. For the time being, a closing remark from Dave Bristow: "There's a big opportunity here for music – you can, with the appropriate software, use a significantly different approach. The idea of melodies, chords and rhythms can go out the window if you like, and you can get right back to basic ideas of strings of notes, and harmony and rhythm being a result of that, rather than a foundation." The sound of 1985, perhaps?

We'll bring you a detailed and critical operational review nearer the release of the CX5, but for now here's a number of preliminary conclusions/suggestions.

1 Yamaha should supply a Voicing Program with the package – it's absolutely essential. And if they want to throw in a Music Composition Program too, whoopee.

2 An educational assault will have to be mounted. FM is very mysterious to novices (ie anyone not owning a DX) and although the CX5's display facilities help to see what's going on with FM, information has got to be made available to musicians. Perhaps the obvious starting point is an FM educational program free with each CX5?

3 This is a musician's tool and not a computer buff's plaything – although the added bonus of games and lists is attractive. The richness of FM sounds along with the way they please the ears, in combination with the control and display facilities of the CX5, is little short of staggering. This instrument seems quite capable of doing what all good musical instruments should do: affect the way music is made, and provoke keener, more thoughtful music from the musician. It won't make you better, but it'll organise more effectively what you can do.

4 When can we have one?


Also featuring gear in this article

(MIC Feb 90)

Fireball CX5M
(ES Oct 84)

(EMM May 86)

(MT Feb 87)

(MT Jun 87)

(MT Dec 87)

...and 3 more Patchwork articles... (Show these)

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


One Two Testing - May 1984

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Computer > Yamaha > CX5M

Review by Tony Bacon

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