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MicroLink System ML10

for Casio MT200 and Sinclair Spectrum

Micro Musical's latest hardware/software package links the Casio MT200 to the Sinclair Spectrum home micro. Somehow, Paul White managed to find time to review it.

British computer music pioneers Micro Musical have introduced one of the most cost-effective systems currently available.

The world of MIDI offers a great deal to those able to afford the luxury of a MIDI system, but now an alternative is available which provides polyphonic sequencing for the Casio MT200 home keyboard, using the popular Sinclair Spectrum microcomputer.

The Casio MT200 represents a break from personal keyboard tradition in that it is fitted with a connector that allows Casio's owm PA1 adaptor to be plugged in, giving compatibility with any computer having a standard Centronics output.

Originally, this was intended for use with Casio's own home computer, but seeing as this is (a) very expensive and (b) not yet available in this country, the system would appear to have got off to a somewhat shaky start. Even if the above obstacles were not present, further problems exist in that the software as written for the Casio computer is, to put it mildly, rather crude. The program runs in BASIC which makes it slow to use, and all the note values must be entered as data statements, an inefficient and somewhat tedious system which renders any user-friendly form of editing quite impossible.

All the program really does is to send a stream of ASCII codes to the keyboard, which is furtively pretending to be a Centronics-compatible printer and therefore produces music instead of text.

In addition to playing notes via the Centronics bus, the machine may be started and stopped, the rhythm machine's six preset patterns selected, and the left-hand auto chord section engaged or disengaged.

Before checking out the system produced by Micro Musical, it's worth looking briefly at the MT200 itself.

The Keyboard

This particular Casio is a four-octave instrument with a small-scale but nonetheless quite usable keyboard, and incorporates eight preset voices, six preset rhythms and the Casio autochord system which operates over the bottom one-and-a-half octaves of the keyboard.

As is typical of organ-based keyboards, none of tine factory sounds is a particularly faithful representation of its title, but all are musically viable - great for playing 'Spanish Eyes' with lots of vibrato... Similarly, the rhythm section doesn't really sound like any type of acoustic drum kit, being if anything more reminiscent of a bag of crisps stuck in the works of a very large clock but, again, its artificial nature does lend the instrument's output a peculiar appeal.

All the sounds may be processed by the MT200's built-in stereo chorus - which on the organ preset gives a fabulous caricature of a theatre organ - and the whole system is eight-voice polyphonic, twin internal speakers being mounted at either end of the control panel for home use or practice.

The Package

In order that the MT200/PA1 combination may be used with a 48K Sinclair Spectrum, Micro Musical have produced a software package and hardware interface, and these are fully approved by Casio who are probably rather relieved at being spared the embarrassment of having to confess to their English customers that the Casio computer is not available.

Taking the system concept further, Micro Musical have produced a wooden desk which keeps the package tidy, and this may be fitted to the stand (which is also included in the price) for home or live use.

Once assembled, the system allows music to be entered from the Spectrum keyboard, and a comprehensive editing facility allows bars to be corrected, transposed, duplicated; or moved so that complete polyphonic compositions may be readily created.

When the compositions are satisfactory (up to eight titles may be held in memory), these may be stored one title at a time on tape for future access.

In Use

Once connected up in accordance with the instructions, the system is ready to load from the software cassette provided: this contains four sample tunes to show you what can be achieved by careful programming.

"The Spectrum is one of those computers you either love or hate; dedicated owners swear by them whilst many others swear at them."

The Spectrum is one of those computers you either love or hate; dedicated users swear by them whilst many others swear at them. Not being a regular Spectrum user, I tend towards the latter category since the multifunction, rubber keyboard takes a lot of getting used to, and the symbols never seem to be where they should be.

The tape is loaded in the usual Spectrum way by typing LOAD" " followed by ENTER, and then pressing PLAY on the cassette machine. A short time later, the program starts by presenting a few pages of introductory propaganda, and after these have been stepped through using the Enter key, the main music entry display appears. Pressing P ENTER at this point rewards you with a rendition of one of the sample tunes, and this repeats until you have read enough of the manual to find out how to stop it: not a pleasant experience unless you're a quick reader!

There is a list of some 30 commands which make the writing, editing, playing and storing of music possible, but since this would make very boring reading in isolation from the system itself, I'll cover the system operation in a more general manner.

Although the owner's handbook was only completed the night before I took delivery of the system, it is both concise and logical and should present few problems to users.


Before you begin entering notes, the computer requires that you answer certain questions regarding your music's key, time signature, rhythm pattern, voicing, and so on, after which you may proceed.

According to the Casio PA1 handbook, the four-beat bar may be divided into 96 time divisions but only even numbers may be used. Repeated checking with a slide rule confirms that this really is a bit of a con, since there are really only 48 usable divisions, a fact which Micro Musical at least have the decency to point out.

The time signature may be chosen to encompass just about any rhythm you have in mind, but in a straight four-beat bar, the note values are as follows:
Semibreve 48
Minim 24
Crotchet 12
Quaver 6
Semi-quaver 3

In order that all the variables are set up before the composition starts, these are usually put into bar zero, and the first command is generally a RESET which puts the keyboard into its default condition, ie. as though it had just been switched on. There is a simple list of codes for rhythm type and voice preset, and these are put in next. For example, T00 selects piano tone, T05 selects vibraphone and so on.

Key entry is a bit tricky, as if you are not playing in C major, the computer asks how many sharps and flats are in your desired key and expects you to know: a bit daunting for the non-musically literate.

The rhythm machine may be on or off in any given bar and may be switched to a different pattern during the course of a song simply by including the new rhythm code in the appropriate bar. Voice changes may be performed in a similar way.

When it comes to programming notes, it's best to convert your music into a table of note values first so that these may be entered quickly via the computer keyboard. A note is identified by a letter and a number corresponding to its name and position on the keyboard, the keyboard octaves being labelled two, three, four and five, with the top C being C6.

Once notes have been entered, these must be given a length value (between one and 48 for a four-beat bar) and then, most importantly, they must be given a note-off command: this also has a length value, enabling rests or staccato effects to be created. This facility allows notes to be left on at the end of the bar so that they may be tied over to the next bar and, with thoughtful programming, the music can be given a surprising amount of feel.

"The computer asks how many sharps and flats are in your desired key and expects you to know: a bit daunting for the non-musically literate."

It must be remembered that if the auto chord facility is used it takes up four of the eight voices available, and this also applies if you wish to accompany your composition manually on the keyboard, which is only possible if you haven't used up all the eight notes in the program.

Once a bar has been completed, it may be transposed or copied in different locations so that a 12-bar blues, for example, can be built up from only one bar of programming using these commands, and a useful repeat code may be embedded in the bar so that complex arrangements can be built up without using a lot of memory space.


If a mistake is made, which is almost a certainty, individual bars may be displayed and a cursor system used to identify the offending part. This is then removed using the KILL command and replaced with whatever you think is correct. At the end of each bar, the computer adds up the note-on and note-off durations, and if the total doesn't add up to the correct bar length, it drums its electronic fingers (or digits) until you do something about it. If you enter a wrong command, the computer types up PARDON? Personally, I'm sure I could think of some more suitable responses, but then again, this is a family product.

When the recorded composition meets with your approval, it can be stored on cassette using the XSAVE command and this is given a title or filename not exceeding ten letters.

The loading and verification of files is fairly straightforward and no unforeseen problems were encountered in this area, although you must remember to remove the earphone plug from the cassette machine when recording, in the usual Spectrum fashion.


Many modern music products come with handbooks informing you that their capabilities are limited only by your imagination, a phrase much used by the industry that usually means you'll have exhausted all the equipment's possibilities within a couple of hours.

The Micro Musical package does not, in fact, fall into this category. Its limitations are defined by the sounds available and by the tenacity of the user, as it can take all evening to type in a piece of music.

Given that the system is limited by the specification of the MT200 keyboard and by the fact that sequences cannot be entered in real time from that keyboard, the system works very well indeed, the editing facilities being particularly flexible. The educational value of the system is potentially very high and, if you buy the whole package including the desk and stand, you save something like £22 off the individual component cost and get absolutely everything you need to get things working, except the colour TV.

The Casio keyboard may still be used on its own when required, and no doubt the Spectrum computer will be called upon to play a game of Intergalactic Megadeath from time to time, and this is another aspect of the system's inherent flexibility.

Micro Musical are already considering updates for the system, and these include conventional on-screen musical notation and other refinements. It's also possible that note entry from the Casio keyboard may be added in the future, but no firm decision has yet been taken on this.

It's my hope that Casio will at some time in the future produce more adventurous keyboards that can interface with this system, as the MT200, although undoubtedly good value for money, is not going to satisfy many professional musicians or even discerning amateurs.

Micro Musical have turned what could have been a technological disaster into a flexible and educational composition system, and it's nice to see the British sorting out Japanese problems, instead of the other way round.

The complete package costs £389, but for anyone who already has some of the items required, all the relevant component parts are available separately.

Further information: Micro Musical, (Contact Details).

Previous Article in this issue

Cutec MX1210 Mixing Console

Next article in this issue

Roland MPU401 MIDI Processing Unit

Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.


Electronics & Music Maker - Sep 1984

Review by Paul White

Previous article in this issue:

> Cutec MX1210 Mixing Console

Next article in this issue:

> Roland MPU401 MIDI Processin...

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