SPECTRUM MAKES MUSIC

An unusual and costly device for the Spectrum is MIDI interface manufactured by Siel (UK) Ltd. MIDI stands for Musical Instrument Digital Interface and it is a standard format for the exchange of information between digital musical instruments, those typically being keyboard instruments such as synthesisers. The information it handles is the pitch of the note, duration of the note and dynamic information such as the speed at which the key has been pressed.

It was decided to test the Siel interface on the Siel DK600 synthesiser and the Siel Expander - although it will drive any MIDI compatible instrument - using two Siel software cassettes, the Live Sequencer and Expander Editor, both for the Spectrum.

The instructions for connecting instruments to the interface were a little confusing, and Siel would do well to give more explanation here, although its instruction manual gives the full protocol of the MIDI standard, invaluable if you want to write your own programs for it.

With the DK600 connected to the Spectrum via the MIDI interface, the Live Sequencer allows the computer to record a single polyphonic track in real time as you play it on the keyboard. It can then play it back. There is a function for varying the tempo of playback and for producing refrains by looping. When you have perfected your tune you can save it onto cassette for later use.

The second piece of software, the Expander Editor, is for the Siel Expander. The Expander is just another DK600 synthesiser but has no keyboard or controls. To set it up you can either load it from the DK600 or from the Spectrum using the Expander Editor. That gives a high resolution graphics display of the controls, and via menu and graphics options all the controls can be set from the Spectrum.

You can judge when you have set up the sound by using the pre-programmed note and chord sequences and adjusting until they are correct. It also has a HELP facility for explaining what effect the controls have on the sound. A very nice piece of software indeed.

The whole system is very impressive and of high quality and, as you may by now be thinking, it is not cheap.

The MIDI interface retails at £99.00 including the Live Sequencer. If brought separately, the latter is £22.00. The DK600 six voice polyphonic synthesiser is £999.00 and a six voice Expander is £649.00. Siel is bringing out the MK9000 keyboard instrument which will retail at £449.00. The Expander Editor costs £53.50. Siel is planning more software for the Spectrum and if you are interested in music you should look at the Siel range. In terms of technical ability and ease of use it is good and inexpensive compared to other equipment on the market.

Siel (UK) Ltd, is at Ahed Depot, Reigate Road, Hookwood, Horley, Surrey, RH6 0AY. Tel: (02934) 76153/4.

A MUSICAL INTERFACE

Rosetti Ltd has produced a range of hardware and software products home micros, using the Midi interface. Midi stands for Musical Instrument Digital Interface and is used in most professional synthesisers and other electronic instruments.

It allows you to control the instrument via the interface. You can also take the sounds and wave forms from the instrument and send them back through the Midi connector.

With a Midi interface on your micro, you can link a synthesiser to it. You can then play the instrument through the computer. For example, you can compose tunes in the memory of the micro and play them "live" through the synthesiser. If you want to change a single note of the tune then the program will let you. What's more, you can control up to six instruments through a single computer.

You can also record a tune which you play on your synthesiser, put it straight into the micro's memory and then play it back. A 48k Spectrum can hold around half an hour's music.

A Midi interface is available for the Commodore 64 or 48k Spectrum. Commodore units start at under £30, while Spectrum links start at £90. Software is extra, though. Details on 01-253 7924.

THE MUSICAL MIDI

A specialist application for the Spectrum unveiled by Ray Elder

Early one evening recently found me motoriing east towards Basildon, I had been invited to the home of Mr. Mike Beacher for a demonstration of an interface and software he was producing to work with the latest development in musical keyboards.

The most expensive keyboard synthesizer instruments are now being fitted with what is known as a Midi interface, but in line with most electronic developments, the cost of these are rapidly decreasing. Casio plan to have one of the cheapest marketed before this is published at under £300.

So what is it and why was I going to see him rather than have one sent to me at the office?

Well to answer the last question first, when I rang Mike he was reluctant to send one as he insisted that to really appreciate the capabilities of the interface and software it needed to be seen in a professional studio environment. So off I went to visit him.

THE PERFORMER

The actual interface simply connects the instrument to the Spectrum. In fact Mike is producing interfaces for most computers, but said that he preferred the Spectrum because of it's large memory, cost and ease of use.

The interface in it's pre-production state consisted of a small box connected to the Spectrum by a ribbon cable, and with three DIN sockets to the sound source. A pulsing LED indicated that the connection was OK.

What is special about this Midi system is that the signals to and from the interface are not musical notes or sound, but are pure electronic signals which contain all the information needed by the keyboard to produce the sound.

This means that not only the note, pitch and duration is sent but also the voice (type of sound), pressure, volume and all the other sophisticated information required to recreate a sound is being supplied.

It follows that if all this information can be stored (and what better than a computer to do so) and then sent back to the instrument, the sound can be recreated.

The computer actually operates and PLAYS the instrument!

And this is the exciting and innovative difference between the Midi interface and the usual sound output.

PROGRAM

Programs to control and make use of the possibilities of this system have been developed by Mike and a team of freelance programmers.

Mike is eminently suitable to work on this area as he is a very musically talented ex-music teacher, he is also full of enthusiasm and energy for this system.

Several programs are under development and several are available now. He demonstrated one which provided a library of sounds programmed for a synthesiser, although usually a selection of preset voices are provided, the full potential of the infinitely variable settings of the sound envelope is rarely explored. As well as providing an extensive built in set up library the program offered a visually stunning option to define your own sounds.

This was a simple to use way of approaching an extremely complex featured of modern keyboards, anyone who has been playing with one of the sound add ons will have some idea of the complexity of programming the comparatively simple AY chip. A cursor controlled visual display of all the parameters certainly helps when setting up your sound.

I could have played for hours with this program alone.

Another program allowed music which had been "recorded" to be displayed on both screen and printer in manuscript form, as this original music could be transcribed to any key under simple software control the possibilities for anyone involved in orchestral work were obvious.

The final program demonstrated was to me the most exciting and impressive of all. It was a program to turn the Spectrum into an eight channel recorder of the Midi signals.

Each tack has a wide range of options which make it very versatile indeed. Rather than simply list them I'll describe a demonstration Mike did which may give you some idea of the practical usage.

PERFORMANCE

First he set his mastersynth. to a bass guitar voice, set the track to 1 and set a channel on the display to 2. He then "recorded" a piece of music.

Next Mike set his master synth (he had at least six instruments connected!) to a piano voice, set the channel on the display to 3 and recorded a rhythm on track two, while listening to the original track being replayed.

He recorded five tracks in all each with a different channel number and then he set up each of the other synths.

Each synth could be switched to a channel corresponding to the channel number which was selected when recording and so on playback each synthesiser played back separately its own part in the appropriate voice.

The sound was fantastic, as if a full group or orchestra were playing especially when the Midi drum machine was added with fully programmable and synchronised accompaniment.

Then of course there was so much control over speed and editing that even the best tape system couldn't match it.

Mike finally recorded the lot onto a cassette and I listened to it all the way back to the office while scheming how to persuade my boss that I ought to have one for the magazine! I also realised that Mike had been right to insist I visit him.

ENCORE

There are many more features and applications which are possible and I emphasise that this article is only scratching the surface of the capabilities of this system.

I forecast that soon no professional recording studio will be without a comparable system and that all serious musician will start to build a system of their own at home. Schools in particular would find it very valuable indeed, and some authorities and educational organisations have shown a good deal of interest.

Mike himself says that he finds it exciting that it will soon be within many people's budget to buy a keyboard, interface and computer and create high quality music which could be the basis of much more sophisticated systems as their equipment is added to and upgraded.