BBC Micro Music Masterclass
We have now come to the end of our voyage of discovery into ways of making music on the BBC Microcomputer. Of course, we have by no means covered all the possible and useful methods and techniques which can make our quest more enjoyable. Instead, I have imparted to you what I consider to be a good starting point for further explorations of your own. My choice of subjects and programs has been made from the standpoint of a professional musician - and computer enthusiast. All I can hope is that the material contained in these pages will have inspired you to experiment further in this totally fascinating field of pleasure and endeavour.
It should now be possible for you to combine and expand various programs in order to create practical musical tools in whatever area grabs your interest most firmly. Some of the graphics techniques used in Chapter Seven could greatly enhance the sequencer programs contained in the Applications chapter. Autocompositional techniques could well provide bass accompaniment to the three-note organ program. The drum synth program could be combined with the microcomposer program, in order to create rhythm and melody parts synchronised together. As you can see, the possibilities are endless!
Of course, there are also various other techniques which I have not had the time or space to explore in depth which should be tried at your leisure. It should be possible not only to step a synthesiser program externally, either in the fashion I indicated via the analogue interface or else employing the user port, to allow interconnection and synchronisation between synths, drum machines or other Micros (BBC or otherwise). The opposite could also be tried, i.e. triggering a drum machine from pulses generated at the user port or one megahertz bus. The possibilities are within your grasp now, so forge ahead and expand the musical cosmos.
I also need to mention again that one of the major limitations of the BBC SOUND command is the poor resolution possible for the timing of duration. As stated earlier on, for most practical musical purposes 1/20th of a second is, generally speaking an insufficiently small timing increment, but in many of the programs included in the text I have made do with this limitation, for the sake of additional simplicity and clarity. All the programs that fall into this category are intended as a demonstration of a particular programming technique and should therefore be altered to incorporate one of the other timing methods when it comes to practical use.
My autocompositional method is based on a thorough practical knowledge of musical composition and improvisation. This knowledge was used to provide the computer with a set of rules to constrain its random number generator and choose musical-sounding note patterns. A more mathe-matical, although still artistically manipulated, technique has been explored by Jim McGregor and Alan Watt in their excellent book, Advanced Programming Techniques for the BBC Micro. The authors employ first, second and third order probability tables of various melodies. These tables tell the computer the most likely preceding and subsequent notes and thereby constrain the computer’s random choice of notes in a different way. Since I saw no point in duplicating their already published work, I have presented an alternative method which relies on a more directly pragmatic and practical approach to the technique.
Autocomposition just about touches on a currently fashionable area of computer programming, namely artificial intelligence and expert systems. Might it be possible, rather than teaching the computer your own set of musical rules, to let it develop its own? You would then only have to act as a computer critic or A and R man giving the BBC the thumbs up or thumbs down for each new work it produced. An exciting and daunting thought, and, copping out somewhat, I will leave entirely up to you as to precisely how you might go about tackling this mammoth task!
One of the important subjects I have barely touched on in this study is that of interfacing. I make no excuses for this omission, as it is a large and complicated subject in its own right. There is, however, one type of interface which I should mention before concluding - and that is the MIDI interface.
The reason why this is worth mentioning at this late point in the book is because, by the time you read this, interfacing devices using this new standard are likely to be available for the BBC Micro. This will make it possible to drive keyboards such as the Yamaha DX7 and the Sequential Circuits Prophet T8, as well as various drum machines, direct from the computer, using software based on the microcomposer program and similar techniques. Since easy access to these interface devices is imminent at the time of writing, and they should be readily available at a reasonable price, I came to the conclusion that it would be redundant exploring into the electronic area of chips, transistors, bits and bytes. After all, once commercially available, it will be possible for you to adapt your existing musical software to run these new interface devices. For now, you can sit back and flex your new-found musical muscles using the internal sound chip!
So let me bid you farewell for the moment and leave you in the hope that you will enjoy RUNning and experimenting with the programs in the book just as much as I enjoyed writing them! Computers are the future of music, welcome to the future...
Useful Reading
Magazines:
Acorn User - May 83: ‘Auto composition’
Acorn User - Dec 83: ‘Envelope Shaper program’
Acorn User - April 83: ‘Auto composition’
Electronic Soundmaker: Often has interesting articles relating computing to music.
The Micro User - Jan 84: Note Play program plus general
Sound advice
The Micro User - Dec 83: Sound advice (an extended series
of articles with many helpful hints and tips)
Electronics and Computing - July/Aug 83: A two part series on how to build a digital to analogue synthesiser interface for the BBC. An excellent constructional project for the more technical amongst you.
Books:
The BBC Micro Book by Jim McGregor and Alan Watt
This book has a clear introductory chapter on SOUND and ENVELOPE Advance Programming Techniques for the BBC Micro. It deals with multi-channel synchronisation, plus a mathematical approach to automatic composition using probability tables.
Computers in Music by John Hammond
A comprehensive coverage of computer-based musical instruments from the Casio to the Fairlight.
The Advanced User Guide by Bray, Dickens and Holmes
A vital tool for further exploration into interfacing techniques. This book is filled with useful technical information about the BBC.
If you have any problems finding information about computer
music and the like, there is a company who keep a library of
current books, leaflets, technical manuals, etc. They are called
ESSP. (Electronic Synthesiser Projects) and can be contacted at
the following address: ESSP, The Sound House, PO Box 37b, East
Molesey, Surrey, KT8 9JB
Telephone: (01) 979 9997.