Musical Epilations of the 2\Tdtl ST's
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Musical epilations of the 2\tdtl ST's ftA Tenfold BERNARD BABANI (publishing) LTD THE GRAMPIANS SHEPHERDS BUSH ROAD LONDON W6 7NF ENGLAND Please Note Although every care has been taken with the production of this book to ensure that any information, projects, designs, modifications and/or programs etc. contained herewith, operate in a correct and safe manner and also that any components specified are normally available in Great Britain, the Publishers do not accept responsibility in any way for the failure, including fault in design, of any information, project, design, modification or program to work correctly or to cause damage to any other equipment that it may be connected to or used in conjunction with, or in respect of any other damage or injury that may be so caused, nor do the Publishers accept responsibility in any way for the failure to obtain specified components. Notice is also given that ifequipment that is still under warranty is modified in any way or used or connected with home-built equipment then that warranty may be void. The author used ATARI ST computers and versions of software that were available in Great Britain at the time of writing this book. Certain details may vary with versions of these machines for other countries, and with versions of software sold in other countries. © 1988 BERNARD BABANI (publishing) LTD First Published - September 1988 Reprinted - April 1991 British Library Cataloguing in Publication Data Penfold, R. A. Musical applications of the Atari STs. 1. Music. Applications of Atari ST micro computer systems I. Title 780'.28'54165 ISBN 0 85934 191 7 Set from disc by Commercial Colour Press, London E.7 Printed and Bound by The Guernsey Press Co. Ltd, Channel Islands Preface Not so very long ago there was no clear leader in the This book is aimed at the musician who wishes to music computer stakes, with the possible exception of exploit the potential of the ST computers in music the Commodore 64. However, several computers were applications. This mainly means using the ST in MIDI quite popular for music applications, with the Com systems, and much of the book is devoted to a modore 64 being just one of several machines with a description of MIDI in general, MIDI as it applies to the respectable range of music oriented software available, ST, and running MIDI applications on the ST. A as was the Atari ST. The "64"was the most popular, knowledge of computing is certainly an asset, but most but did not dominate the market. The ST gradually of the information is usable by someone with little overhauled all the competition, including the "64". knowledge of computing. It is assumed though, that Once it gained a good lead the situation changed quite the user has a basic knowledge of using the ST and rapidly, with the ST becoming very much the music running programs on it. The small manual provided with computer. It now has an unrivaled (but still rapidly the ST provides instructions on using the mouse, expanding) range of available software and music running applications programs, etc., and this is all the add-ons. With its built-in MIDI ports, large memory, preparation you should need. For those who are more excellent graphics, high processing power, and quite technically minded and favour the do-it-yourself moderate cost, it is perhaps the obvious choice for approach, there are chapters covering some simple demanding music applications such as MIDI hardware projects, programming the ST's sound chip, sequencing, and its sudden leap to total dominance is and MIDI programming (including some useful MIDI not really all that surprising. processing routines). R. A. Penfold Acknowledgements Fast BASIC is a registered trademark of Computer Concepts, Gaddesden Place, Hemel Hempstead, Herts., HP2 6EX. ST and ST BASIC are registered trademarks of Atari Corporation, Sunnyvale, CA 94086, U.S.A. Notator is a registered trademark of C-LAB Software, Postbox 70 03 03, 2000 Hamburg 70, Germany, whose U.K. agents are Sound Technology PLC, 6 Letchworth Business Centre, Avenue One, Letchworth, Herts., SG6 2HR. Hybrid Arts EZ-Track and EZ-Score are registered trademarks of Syndromic Music, 24—26 Avenue Mews, Muswell Hill, London, N10. Contents Page Chapter 1. THE INTERNAL SOUND GENERATOR 1 BASIC Sound Generation 2 WHILE ... WEND 3 Chip Description 4 The Registers 5 Accessing The Registers 7 Chapter 2. MIDI CONNECTIONS 9 MIDI Advantages 9 MIDI Wiring 10 ST MIDI Ports 11 Basic Connections 11 Star System 14 More Complex Set ups 15 Merging 16 Channel Limitations 20 Multiple Outputs 20 Chapter 3. GETTING THE MESSAGE 22 Modes' 22 Mode 1 22 Mode 2 22 Mode 3 22 Mode 4 22 Beyond Mode 4 23 Transmission Modes 24 Note On/Off 24 Key Pressure 24 Controls 25 Mode Change 25 Program Change 25 Pitch Bend 26 System Messages 26 Song Position Pointer 26 Song Select/Tune Request 27 System Exclusive 27 System Real-Time 27 Finally 28 Chapter 4. MIDI TECHNICALITIES 29 The Interface 29 The Hardware 31 MIDI Codes 31 Note On/Off 31 Key Pressure 31 Control Change Etc 31 Pitch Wheel 32 Program Change 32 System Messages 32 Chapter 5. APPLICATIONS PROGRAMS 34 Sequencing 34 Why ST Sequencing? 34 Real-Time Sequencing 35 Filtering 37 Quantisation 38 Editing 40 Event Editing 41 Notation Programs 42 All In One Approach 44 Page In Practise 45 Other Program Types 47 Visual Editors 49 PD Software 50 Some Programs 50 MIDI Instruments 51 Chapter 6. ST ADD-ONS 53 THRU Box 53 The Circuit 54 Construction 55 MIDI Mixer 58 The Circuit 58 Construction 59 MIDI Switcher 59 CV/Gate Controller 63 Which Port? 64 The Circuit 65 Parallel Port 67 Adjustment 68 Programming 70 Chapter 7. MIDI PROCESSING 72 MIDI Processing 72 Channelising 73 ST Languages 76 Note Separator Program 77 Fast BASIC Version 78 Channel Shifting 80 Filtering 81 Perfect Harmony 82 Velocity Control 83 All Change 84 MIDI Terminal 86 Effects 87 Real-Time 87 Hardware 87 Index 89 Chapter 1 THE INTERNAL SOUND GENERATOR The ST range of computers have gradually established by a colour television might not be very good, and if themselves as the standard machines for electronic programs that will only run in a colour mode are to be music applications, ousting the Commodore 64 from used a great deal, there is no real substitute for a good this position. The inclusion of MIDI ports on all the ST colour monitor. Most music software seems to be computers obviously played a big part in this success, usable in medium resolution colour or high resolution but a few other computers have been similarly equipped monochrome, but there have been a few that are but failed to gain widespread acceptance amongst monochrome only (although mostly seem to have been music users. The ST computers do not just have built-in modified so that the current versions also run in colour). MIDI ports in their favour, they use the powerful 68000 There may be a few music programs that will only run in microprocessor, have excellent graphics capability, one of the colour modes, but I have not yet plenty of memory even in the basic models, and are encountered one. It is perhaps worth mentioning that quite affordable. They really do deliver Atari's promise the quality of the ST monochrome display is absolutely of "power without the price"! superb. Unless a program makes really good use of There are several versions of the ST from the original colour I have no hesitation in opting for monochrome 520ST to the new "Mega" STs with their massive operation. memory. The 520ST models have been gradually The standard version of the 520ST at the time of improved over the years. Originally the operating writing this book is the 520STFM, which has both a the system had to be loaded from disc each time the television modulator and a floppy disc drive built-in. computer was used, leaving little memory free for Floppy discs are used for program and data storage, applications programs. Later models have the operating and virtually all software for the ST computers is only system built-in on ROM chips so that a large proportion available on disc. The STs do not have a cassette port, of the RAM is left free (and most owners of the early and little software is available in cartridge form (I think machines have now had the ROM chips fitted to their that all STs are equipped with a cartridge port). Even machines with cartridge software you might still need a disc drive The 520STM has a built-in modulator so that it can for data storage. An ST computer is of very limited use be connected to a television set which will act as a without a disc drive. If you have an ST without a built-in colour monitor. This is a useful addition, as many disc drive you will certainly need to buy an external drive people who are primarily interested in using the ST for before you can use it properly (or use it at all) in music music applications opt for the monochrome monitor. applications. The built-in drive of the original 520STFM The built-in modulator allows programs that run in the was single-sided type having a formatted capacity of low or medium resolution colour modes to be run about 360k. This is adequate for most purposes, but without having to go to the expense of buying a colour there are some programs that require a double-sided monitor. However, the quality of the display provided drive with its 720k formatted capacity.