Not a bad month for computerised musical goodies this month. In fact, some of the most exciting releases are additions to existing systems, which proves the old adage about many a mickle making a muckle. No, sorry, wrong adage. The adage we had in mind was the one about computers being software-updateable as opposed to hardware-specific, but that one doesn't flow from the pen quite so well.

Rural sayings apart, it is a happy fact that computers will do more or less whatever you tell them, and if you think of something more complex to tell them, there's a good chance that they'll go right out and do it. Take the Yamaha CX-5 Music Computer — Yamaha themselves only told the poor machine how to record multitrack music in step time, and now Digital Music Systems have taught it the intricacies of real-time composition.

That's an enormous advantage, because the CX-5's main drawback at the time of release was the rather inflexible FM Composer package and its lack of live orientation. The machine sounded fine — it has a built-in DX-9 voice card, with an improved DX-100 type voice card on the way — but cost and inflexibility (and an impending CX-7 model?) have forced its retail price down.

The DMS-1 Real Time Sequence/Recorder is an £86 cartridge which slots into the top of the CX-5. At that price it's nearly three times the cost of Yamaha cartridges and almost a third of the new price of the computer itself (around £300 with music keyboard). But it can make the whole system much more accessible to the average user.

Switching on the power presents you with the first of a series of menus. Nothing flashy in the presentation — in fact, the stark display of numbers and letters can become confusing in some modes — but at least it does the job. Music is composed from a series of phrases, each with an index number, in which parts are shared between the CX-5's eight voices. So you could use three voices to write some three-note string chords, one for a bass line, two for a harmony and a couple for melodies and effects.

You can use the CX-5's own preset sounds, or sounds of your own creation loaded from tape, or any of the (rather bland) sounds which come built into the DMS-1 cartridge. Of course, you could choose to control some other MIDI synth from the CX-5 and use those sounds instead.

Music is entered 'live' from the music keyboard with the help of a metronome click. Time signature, tempo and number of bars to be recorded are decided in advance and the complete phrase is inserted into a scrolling list at any point(s) desired. You can get any section to play with any sound, but unlike Yamaha's cartridge you can't change sounds once the piece has started. This means you're stuck with the eight (or fewer) start-up sounds, so there's no chance of saving channels by putting different material (for instance, lots of different drum sounds) on one or two channels.

You can time-correct your playing to make it a little more regular (as usual, you have to be careful your original phrase isn't changed beyond recognition) and transpose any part. You can also edit and correct phrases a note at a time, so it's strange that the package doesn't give an option of composition from scratch using step time.

The DMS-1 package is pretty easy to use, although it does require a degree of advance planning. For instance, in the Phrase/Sequence Editor section the bar lengths of each phrase are indicated, but since you can only 'see' one section at a time on screen (no zippy pull-down options here!) you'll have to remember the exact bar lengths of all your other sections if you want things to match up. The manual's pretty slim too, and although the system's fairly easy to get into, it would be nice to have a little more reference material in case of difficulties.

Still, DMS have achieved something denied so far to Yamaha, even if it is at a price. Existing CX-5 owners may well be happy to pay that price — prospective purchasers should be able to find the extra cash too, now the machine itself is so inexpensive.

In fact the CX-5 will be an even better proposition soon, after Yamaha introduce the SFG05 Tone Module. A direct replacement for the existing tone module, it's based on DX100 circuits and expected to cost under £100. Since it features MIDI In, it will allow the CX-5 to be used as a MIDI Expander, which makes it even better value for money. Yamaha also have some new software for the machine coming up, and we'll take a look at the new packages as soon as possible.

Now for an update on one of our favourite computer music systems, the Greengate DS:3. Every time this Apple-based 'baby Fairlight' looks like becoming outdated, the company surge ahead with some new idea or other and keeps the Mirages, Prophet 2000s and Akai Samplers of this world effectively at bay.

The latest achievement is to make the system fully MIDI-compatible, offering external control of its four independent samples with full dynamic response. MIDI In and Thru are available on an interface box connected to the new MIDI card fitting inside the Apple computer, and the MIDI Out socket will become active with the next software update. The MIDI Clock In is already functional, so the DS:3's sequencer can be clocked from external sources such as drum machines or other sequencers. The new MIDI-compatible software disk is Rev 1.4B, and Greengate hope to market a MIDI control keyboard to supersede the existing DS:3 keyboard later this year.

Existing DS:3 users have already had the opportunity to buy a very cheap Digital Delay software disk, and the latest revision of the Greengate EPROM Blower software is now out. The EPROM card allows you to use your DS:3 to prepare chips for drum machines such as the Linn, Drumtraks and Oberheim from a bank of DS:3 library sounds or from any sound you can imagine or sample yourself. With commercial chips at up to £70 each, you could buy a whole DS:3 system and blow your own at a fiver a time for the cost of two or tree commercial chip sets.

A new Long Sample Time Hardware extension, MEG-1, is now available from Greengate, and this allows you to record up to 30 seconds of sound monophonically with full bandwidth (of course, you could always spend £4,000 on an AMS digital delay, or £40,000 on a Synclavier...). MEG-1, at around £460, also allows you to store up to 24 sounds for instant pull-down for conventional polyphonic playing, so although you'd still need to take your Apple disk drives to a gig, you won't need them once you've loaded sounds to the new card.

What else? Well, for £57 you can buy a new software package for Digital Synthesis, ADSR Control and Envelope Shaping, (SYN-1) which allows you to define sounds from scratch using harmonic synthesis and to assign envelopes to them or to sampled sounds. And Greengate are now working on the DS:4-8 (an eight voice eight-bit system with extended sampling times) and the DS:4-16 (a true 16-bit system with a variable number of voices). Looks like a busy year for Apple dealers.

On the subject of updates, we looked at the SpecDrum system for the Sinclair computer a while back, and concluded that at around £30 it represents tremendous value for money since its sampled drum sounds are on a par with those of the £250 Korg DDM 110.

Now the SpecDrum can compete with the DDM 220 as well, because its manufacturers, Cheetah Marketing, have released an Alternative Sound Set of Latin Percussion on cassette. The new set includes Kick Drum, Hard Snare, Hi Timbale, Lo Timbale, Hand Cowbell, Stick, Cabasa and Tambourine, plus an editing routine enabling you to assemble your own kits from any of the existing sound sets. Cheetah hope to market a new set every eight weeks and at £3.99 a time they seem excellent value for money. The system's available from Boots The Chemist computer departments.

Now a couple of quick plugs for a couple of good mates, specifically for one record and one book. The record is The AMP Records Compilation Album, the first release from a new London-based label specialising in synthesizer/computer music. The album features three artists and covers styles from ambient music, electro-disco and Eastern-influenced pieces to synthesiser instrumentals and even a sampled piano solo. Instrumentation includes the DS:3, Roland MSQ-700, Akai Sampler, Prophet 600, Yamaha DX-7, Roland Jupiter 6 and Juno 106, software-updated SCI Drumtraks and more.

AMP Records plan to release a whole series of synthesiser/computer music albums, initially by mail order from AMP Records, (Contact Details) (cheques & PO's for £5.29 should be made payable to AMP Records). A full catalogue of forthcoming releases is now available.

Introduction To Keyboards and Computer Music by Philip Hawthorn with Vince Hill and Peter Howell (Usborne, £4.95/£2.50 paperback) is a pictorial, highly illustrated guide to the field. It explains the relationship between keyboards, computers and the music industry, looks at sound generation on a home computer, the basics of keyboard, guitar and expander synthesisers, MIDI interfacing and composition.

There's a music program listing suitable for the Commodore 64, MSX, BBC, Electron, VIC 20 and Spectrum computers, a shorty buyer's guide to home keyboards and software, and a glossary. Hawthorn's book aims at the young, with a simple vocabulary and light-hearted presentation, but it could be useful for the complete MIDI/computer music beginner (your bassist perhaps?) or anybody who finds the music business increasingly dominated by intimidating little boxes connected to TV screens.

Digital Music Systems, (Contact Details)
Yamaha UK; (Contact Details)
Greengate Productions, (Contact Details).
Cheetah Marketing, (Contact Details).
AMP Records, (Contact Details).