Desktop Audio Technology: Digital audio and MIDI principles

by Rumsey; Francis

• ISBN13: 9780240519197
• ISBN10: 0240519191
• Format: Nonspecific Binding
• Copyright: 2003-10-20
• Publisher: Routledge

Summary

In this thorough introduction to the technology behind audio workstations, Dr Francis Rumsey explains not only how digital audio works but also how to make best use of its capabilities. A combined revision of his two successful titles, MIDI Systems and Control and The Audio Workstation Handbook, this new book covers recent developments such as surround sound formats, direct stream digital, new audio project formats, new interfaces and alternatives to MIDI. Desktop Audio Technology begins by setting out principles of digital audio and how these are applied in recording, replay and editing within workstations. MIDI and synthetic audio control is then covered, looking at the means by which artificial sounds can be controlled and manipulated. This is followed by explanations of hardware, including storage devices, buses, computer interfaces and audio processing options. Dr Rumsey then focuses on transferring audio between systems, including coverage of audio interfaces, networking and file formats. The next section examines audio software, providing working examples of different commercial packages that exemplify some of the concepts previously described. The final chapter considers operational issues such as recent spatial reproduction formats, consumer format mastering and quality control issues, as well as troubleshooting and systems issues. If you are a student, lecturer or practitioner in the field of audio and are looking for an authoritative technical guide to the underlying principles of digital audio and MIDI, this book is for you. Dr Francis Rumsey is a Reader in Sound Recording at the University of Surrey (UK) and a Visiting Professor at the School of Music in Piteå (Sweden). He is a Fellow of the Audio Engineering Society and a regular contributor to the AES Journal. Dr Rumsey is also author of Spatial Audio and co-author of Sound and Recording (with Tim McCormick) and The Digital Interface Handbook (with John Watkinson), all published by Focal Press.

Table of Contents

Series introduction	xiii
1 Introduction to desktop audio technology	1	(4)
1.1 About this book	1	(1)
1.2 Audio workstations	2	(1)
1.3 Audio and the computer industry	3	(1)
1.4 Audio and quality	3	(2)
2 Digital audio principles	5	(53)
2.1 Analog and digital information	5	(2)
2.2 Binary number systems	7	(4)
2.2.1 Basic binary	7	(2)
2.2.2 Negative numbers	9	(1)
2.2.3 Fixed- and floating-point representation	10	(1)
2.2.4 Logical operations	10	(1)
2.3 Basic A/D and D/A conversion of control information	11	(2)
2.4 A/D conversion of audio signals	13	(19)
2.4.1 Audio sampling	13	(3)
2.4.2 Filtering and aliasing	16	(2)
2.4.3 Quantisation	18	(3)
2.4.4 Relationship between sample resolution and sound quality	21	(1)
2.4.5 Use of dither	22	(5)
2.4.6 Types of dither	27	(2)
2.4.7 Oversampling in A/D conversion	29	(1)
2.4.8 Noise shaping in A/D conversion	30	(2)
2.5 DIA conversion	32	(1)
2.5.1 A basic D/A convertor	32	(1)
2.5.2 Oversampling in D/A conversion	33	(1)
2.6 Sound quality versus sample rates and resolutions	33	(5)
2.6.1 Psychoacoustic limitations	33	(1)
2.6.2 Sampling rate	34	(3)
2.6.3 Quantising resolution	37	(1)
2.7 Direct Stream Digital (DSD)	38	(1)
2.8 Changing the resolution of an audio signal (requantisation)	39	(2)
2.9 Dynamic range enhancement	41	(1)
2.10 Error correction	42	(2)
2.11 Introduction to digital audio signal processing	44	(7)
2.11.1 Gain changing (level control)	44	(1)
2.11.2 Crossfading	45	(1)
2.11.3 Mixing	46	(1)
2.11.4 Digital filters and equalisation	46	(2)
2.11.5 Digital reverberation and other effects	48	(1)
2.11.6 Dynamics processing	49	(1)
2.11.7 Sample rate conversion	50	(1)
2.12 Audio data reduction	51	(6)
2.12.1 Why reduce the data rate?	51	(1)
2.12.2 Lossless and lossy coding	52	(1)
2.12.3 MPEG - an example of lossy coding	53	(3)
2.12.4 Other data-reduced formats	56	(1)
Further reading	57	(1)
3 Recording, replay and editing principles	58	(21)
3.1 The sound file	58	(1)
3.2 RAM buffering	59	(3)
3.3 Disk drive performance issues	62	(2)
3.4 Allocation units or transfer blocks	64	(1)
3.5 Multichannel recording and replay	64	(4)
3.5.1 Multitrack or multichannel?	64	(1)
3.5.2 Inputs, outputs, tracks and channels	65	(1)
3.5.3 Track usage, storage capacity and disk assignment	66	(1)
3.5.4 Dropping-in	67	(1)
3.6 System latency	68	(1)
3.7 Principles of audio editing	69	(10)
3.7.1 Advantages of non-linear editing	69	(1)
3.7.2 Sound files and sound segments	69	(1)
3.7.3 Edit point handling	70	(1)
3.7.4 Crossfading	71	(2)
3.7.5 Editing modes	73	(4)
3.7.6 Simulation of 'reel-rocking'	77	(2)
4 MIDI and synthetic audio control	79	(53)
4.1 Background	79	(2)
4.2 What is MIDI?	81	(1)
4.3 MIDI and digital audio contrasted	81	(1)
4.4 Basic MIDI principles	82	(3)
4.4.1 System specifications	82	(1)
4.4.2 Simple interconnection	83	(1)
4.4.3 MIDI channels	84	(1)
4.4.4 Message format	84	(1)
4.5. MIDI messages in detail	85	(12)
4.5.1 Channel and system messages contrasted	86	(1)
4.5.2 Note on and note off messages	86	(1)
4.5.3 Velocity information	87	(1)
4.5.4 Running status	88	(1)
4.5.5 Polyphonic key pressure (aftertouch)	88	(1)
4.5.6 Control change	89	(2)
4.5.7 Channel modes	91	(2)
4.5.8 Program change	93	(1)
4.5.9 Channel aftertouch	94	(1)
4.5.10 Pitch bend wheel	94	(1)
4.5.11 System exclusive	95	(1)
4.5.12 Universal system exclusive messages	95	(1)
4.5.13 Tune request	96	(1)
4.5.14 Active sensing	96	(1)
4.5.15 Reset	97	(1)
4.6 MIDI control of sound generators	97	(9)
4.6.1 MIDI note assignment in synthesisers and samplers	97	(3)
4.6.2 Polyphony, voice and note assignment	100	(1)
4.6.3 MIDI functions of sound generators	100	(1)
4.6.4 MIDI data buffers and latency	100	(2)
4.6.5 Handling of velocity and aftertouch data	102	(1)
4.6.6 Handling of controller messages	102	(3)
4.6.7 Registered and non-registered parameter numbers	105	(1)
4.6.8 Voice selection	106	(1)
4.7 MIDI tuning control	106	(2)
4.8 General MIDI	108	(2)
4.9 Scalable polyphonic MIDI (SPMIDI)	110	(1)
4.10 Standard MIDI files (MF)	110	(5)
4.10.1 General structure of MIDI files	111	(1)
4.10.2 Header chunk	111	(1)
4.10.3 Track chunks	112	(1)
4.10.4 MIDI file track events	113	(2)
4.10.5 Time signatures and tempo maps	115	(1)
4.11 Downloadable Sounds (DLS) and SoundFonts	115	(2)
4.12 RMID and XMF files	117	(1)
4.13 SAOL and SASL in MPEG 4 Structured Audio	117	(1)
4.14 MIDI and synchronisation	118	(7)
4.14.1 Introduction to MIDI synchronisation	118	(1)
4.14.2 Music-related timing data	118	(3)
4.14.3 Timecode and synchronisation	121	(2)
4.14.4 MIDI timecode (MTC)	123	(2)
4.15 MIDI machine control (MMC)	125	(3)
4.16 MIDI over USB	128	(1)
4.17 MIDI over IEEE 1394	129	(1)
4.18 After MIDI?	130	(1)
Further reading	131	(1)
Useful websites	131	(1)
5 Hardware and systems issues	132	(36)
5.1 Storage media	132	(16)
5.1.1 Storage requirements of digital audio and video	132	(1)
5.1.2 Disk drives in general	133	(2)
5.1.3 Disk drive specifications	135	(1)
5.1.4 Magnetic hard disk drives	136	(2)
5.1.5 RAID arrays	138	(1)
5.1.6 Removable magnetic media	138	(2)
5.1.7 Optical disks in general	140	(1)
5.1.8 CAV and CLV modes in optical storage	141	(1)
5.1.9 The magneto-optical (M-O) drive	141	(2)
5.1.10 Phase-change optical recording	143	(1)
5.1.11 Compact discs and drives	143	(2)
5.1.12 DVD	145	(2)
5.1.13 Optical disc filing structures	147	(1)
5.1.14 Tape storage media	147	(1)
5.2 Peripheral interfaces	148	(4)
5.2.1 SCSI	149	(2)
5.2.2 ATA/IDE interface	151	(1)
5.2.3 PCMCIA	151	(1)
5.2.4 IEEE 1394 (Firewire) and USP	151	(1)
5.3 Filing systems and volume partitions	152	(1)
5.4 Formatting, fragmentation and optimisation of media	153	(1)
5.5 Audio processing and synthesis hardware	153	(6)
5.5.1 Introduction	153	(2)
5.5.2 Audio processing latency	155	(1)
5.5.3 DSP cards	155	(1)
5.5.4 Host-based audio processing	156	(1)
5.5.5 Integrated sound cards	156	(1)
5.5.6 Synthesis engines on sound cards	156	(3)
5.6 External synchronisation interfaces	159	(1)
5.7 User interfaces	159	(1)
5.8 Serial control interfaces	160	(5)
5.8.1 RS-232 and RS-422	160	(1)
5.8.2 The basic MIDI interface	160	(3)
5.8.3 MIDI connectors and cables	163	(1)
5.8.4 Interfacing a computer to a MIDI system	164	(1)
5.9 Drivers and audio I/O software	165	(2)
Useful websites	167	(1)
6 Audio formats and data interchange	168	(51)
6.1 Audio file formats	168	(17)
6.1.1 Introduction	168	(1)
6.1.2 File formats in general	169	(2)
6.1.3 Sound Designer I format	171	(1)
6.1.4 Sound Designer II format	171	(1)
6.1.5 AIFF and AIFF-C formats	172	(1)
6.1.6 RIFF WAVE format	173	(2)
6.1.7 WAVE-format extensible	175	(1)
6.1.8 Broadcast WAVE format	175	(2)
6.1.9 MPEG audio file formats	177	(2)
6.1.10 DSD-IFF file format	179	(1)
6.1.11 Edit decision list (EDL) files	180	(1)
6.1.12 AES 31 format	180	(2)
6.1.13 The Open Media Framework Interchange (OMFI)	182	(1)
6.1.14 MXF - the Media Exchange Format	183	(1)
6.1.15 AAF - the Advanced Authoring Format	184	(1)
6.2 Disk pre-mastering formats	185	(1)
6.3 Interconnecting audio devices	186	(1)
6.4 Computer networks and digital audio interfaces compared	187	(2)
6.5 Dedicated audio interface formats	189	(8)
6.5.1 Digital interface types	189	(1)
6.5.2 The AES 3 interface (AES 3)	189	(3)
6.5.3 Standard consumer interface (IEC 60958-3)	192	(2)
6.5.4 Carrying data-reduced audio over standard digital interfaces	194	(1)
6.5.5 Tascam digital interface (TDIF)	195	(1)
6.5.6 Alesis digital interface	195	(1)
6.5.7 Roland R-bus	196	(1)
6.5.8 Sony digital interface for DSD (SDIF-3)	196	(1)
6.5.9 Sony multichannel DSD interface (MAC-DSD)	196	(1)
6.6 Networking	197	(9)
6.6.1 Basic principles of networking	197	(2)
6.6.2 Extending a network	199	(1)
6.6.3 Network standards	200	(2)
6.6.4 Network protocols	202	(1)
6.6.5 Audio network requirements	203	(1)
6.6.6 ISDN	204	(1)
6.6.7 Protocols for the Internet	205	(1)
6.6.8 Wireless networks	206	(1)
6.7 Streaming audio over computer interfaces	206	(10)
6.7.1 Audio over Firewire (IEEE 1394)	206	(4)
6.7.2 Audio over universal serial bus (USB)	210	(2)
6.7.3 AES 47: Audio over ATM	212	(3)
6.7.4 CobraNet	215	(1)
6.7.5 MAGIC	215	(1)
6.7.6 MOST	216	(1)
6.7.7 BSS SoundWeb	216	(1)
6.8 Digital content protection	216	(2)
Further reading	218	(1)
Useful websites	218	(1)
7 Audio software	219	(21)
7.1 Sequencers	219	(8)
7.1.1 Introduction	219	(1)
7.1.2 Tracks, channels, instruments and environments	220	(1)
7.1.3 Input and output filters	221	(1)
7.1.4 Timing resolution	222	(1)
7.1.5 Displaying, manipulating and editing information	222	(2)
7.1.6 Quantisation of rhythm	224	(1)
7.1.7 Automation and non-note MIDI events	224	(2)
7.1.8 MIDI mixing and external control	226	(1)
7.1.9 Synchronisation	226	(1)
7.1.10 Synchronised digital video	226	(1)
7.2 Plug-in architectures	227	(2)
7.2.1 What is a plug-in?	227	(1)
7.2.2 Plug-in examples	228	(1)
7.3 Virtual instruments	229	(2)
7.4 Librarians and editors	231	(1)
7.5 Audio editing and post-production software	231	(4)
7.5.1 Sonic Studio HD	232	(1)
7.5.2 SADiE	233	(2)
7.6 Mastering and restoration software	235	(1)
7.7 Advanced audio processing software and development tools	235	(2)
7.8 Computer music software	237	(2)
Further reading	239	(1)
8 Operational and systems issues	240	(25)
8.1 Level control and metering	240	(2)
8.2 Spatial reproduction formats	242	(7)
8.2.1 Introduction to multichannel formats	242	(1)
8.2.2 4-channel surround (3-1 stereo)	242	(2)
8.2.3 5.1 channel surround (3-2 stereo)	244	(2)
8.2.4 Dolby EX	246	(1)
8.2.5 7.1 channel surround	247	(1)
8.2.6 Surround panning and spatial effects	248	(1)
8.3 Controlling and maintaining sound quality	249	(3)
8.4 Preparing for and understanding release media	252	(5)
8.4.1 CD-Audio 252
8.4.2 DVD	252	(3)
8.4.3 Super Audio CD (ALD)	255	(1)
8.4.4 MP3	256	(1)
8.4.5 MPEG-4, web and interactive authoring	257	(1)
8.5 Synchronisation	257	(2)
8.5.1 Requirements for synchronisation	258	(1)
8.5.2 Timecode synchronisation	258	(1)
8.5.3 Synchronisation to external audio, film or video references	259	(1)
8.6 System troubleshooting	259	(5)
8.6.1 Troubleshooting MIDI	259	(3)
8.6.2 Digital interface troubleshooting	262	(2)
8.6.3 Troubleshooting software	264	(1)
Further reading	264	(1)
Index	265