Audio processes: musical analysis, modification, synthesis, and control

752 Pages·2017·15.72 MB·English

by  Creasey, David J

Audio Processes
Page Intentionally Left Blank
Audio Processes
Musical Analysis, Modification,
Synthesis, and Control
David Creasey
NEWYORKANDLONDON
Firstpublished2017
byRoutledge
711ThirdAvenue,NewYork,NY10017
andbyRoutledge
2ParkSquare,MiltonPark,Abingdon,OxonOX144RN
RoutledgeisanimprintoftheTaylor&FrancisGroup,aninformabusiness
©2017Taylor&Francis
TherightofDavidCreaseytobeidentifiedasauthorofthisworkhasbeenassertedbyhimin
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LibraryofCongressCataloginginPublicationData
Names: Creasey,D.P.(DavidP.),author.
Title: Audioprocesses: musicalanalysis,modification,synthesis,andcontrol/
DavidCreasey.
Description: NewYork;London: Routledge,2017. ©2017
|
Identifiers: LCCN2016012376 ISBN9781138100138(hardback)
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ISBN9781138100114(paperback) ISBN9781315657813(ebook)
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Subjects: LCSH:Computersoundprocessing. Music–Computerprograms.
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Classification: LCCMT723.C722017 DDC786.7–dc23
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LCrecordavailableathttp://lccn.loc.gov/2016012376
ISBN:978-1-138-10013-8(hbk)
ISBN:978-1-138-10011-4(pbk)
ISBN:978-1-315-65781-3(ebk)
TypesetinURWPalladioLbytheauthor
Contents
Abbreviations .... ..... ...... ...... ..... ...... ...... ...... .... xv
Preface .... ...... ..... ...... ...... ..... ...... ...... ...... .... xvii
Acknowledgements .... ...... ...... ..... ...... ...... ...... .... xxi
Chapter1 Introduction ...... ...... ..... ...... ...... ...... .... 1
1.1 TheNatureofAudioProcesses 2
1.1.1 IntroducingAudioProcesses 2
1.1.2 ConstructinganAudioProcess 2
1.1.3 Real-TimeandNon-Real-TimeSystems 4
1.1.4 AudioProcessThemes 5
1.2 ExampleAudioProcessSystems 8
1.2.1 PlayinganAcousticInstrument 8
1.2.2 CombiningTwoPaths 10
1.2.3 AutomatedAnalysis 11
1.2.4 TwoHumansWorkingTogether 13
PART I — ANALYSIS
Chapter2 AudioData Fundamentals .... ...... ...... ...... .... 17
2.1 TheNatureofSound 18
2.1.1 SoundintheTimeDomain 18
2.1.2 CycleLength,Frequency,andAmplitude 19
2.1.3 ConstructionandDeconstructionwithSinusoids 26
2.2 SoundasNumbers 27
2.2.1 Overview 27
2.2.2 SamplingContinuousData 28
2.2.3 ACompleteDigitalAudioSystem 34
2.2.4 ChoosingaSampleRate 35
2.2.5 Amplitude 37
v
vi Contents
Chapter3 Time DomainAnalysis ..... ..... ...... ...... ...... . 39
3.1 BasicConcepts 40
3.1.1 ContinuumofSoundCharacter 40
3.1.2 HarmonicSounds 41
3.1.3 InharmonicSounds 45
3.1.4 PhaseEffects 47
3.2 DynamicSoundCharacter 49
3.2.1 ChimeBar 49
3.2.2 AmplitudeEnvelopes 51
3.2.3 DynamicWaveformChanges 60
3.2.4 Oboe 61
3.2.5 Vibraphone 63
3.2.6 Piano 66
3.2.7 TubularBell 67
3.2.8 Vocal“sh”and“f”Sounds 68
3.3 UsingTimeDomainInformation 70
3.4 LearningMore 72
Chapter4 FrequencyDomainAnalysis ..... ...... ...... ...... . 73
4.1 Introduction 74
4.2 StaticandAverageSoundCharacter 74
4.2.1 SpectralForm 74
4.2.2 FrequencyDomainAnalysisofSimpleWaveformShapes 79
4.2.3 AverageSpectrumAnalysisExamples 84
4.3 DynamicSoundCharacter 89
4.3.1 RepresentingThreeDimensions 89
4.3.2 SimpleSpectrogramExamples 90
4.3.3 MoreComplexSpectrogramExamples 94
4.4 UsingFrequencyDomainInformation 96
4.5 LearningMore 98
PART II — MODIFICATION
Chapter5 BasicModifications .. ...... ..... ...... ...... ...... . 101
5.1 Introduction 102
5.2 SignalFlowControl 102
5.3 AmplitudeControl 105
5.3.1 SimpleAmplitudeControl 105
5.3.2 TwoChannelAmplitudeControl 108
5.3.3 NaturalisticAmplitudeControl 109
5.3.4 WorkingwithDecibels 113
5.4 Mixing 114
Contents vii
5.5 PanControlandStereoBalance 117
5.5.1 MonophonicandStereophonicSignals 117
5.5.2 Panning 121
5.5.3 StereoBalance 125
5.6 CombinationofElements 127
5.6.1 Ordering 127
5.6.2 SeriesandParallelForms 129
5.6.3 PracticalCombinationExamples 133
5.7 DevelopingProcessesandLearningMore 137
Chapter6 Filtering ... ...... ...... ..... ...... ...... ...... .... 139
6.1 Introduction 140
6.1.1 FiltersandAudioProcesses 140
6.1.2 FilteringandAcousticSoundSources 140
6.1.3 MusicalFrequencyRanges 141
6.1.4 Frequency(Magnitude)Responses 143
6.2 StandardFilters 148
6.2.1 LowpassandHighpassFilters 148
6.2.2 BandpassandBandrejectFilters 149
6.2.3 CombandAllpassFilters 152
6.2.4 VariationsinFilterResponses 153
6.3 FilterCombinations 155
6.3.1 CommonSeriesandParallelForms 155
6.3.2 SubtractiveTechniques 159
6.4 FilterDesigns 164
6.4.1 Introduction 164
6.4.2 LowpassandHighpassDesigns 171
6.4.3 BandpassandBandrejectDesigns 180
6.4.4 CombandAllpassDesigns 183
6.5 DevelopingProcessesandLearningMore 193
Chapter7 Distortion .. ...... ...... ..... ...... ...... ...... .... 195
7.1 Introduction 196
7.1.1 AvoidingandCreatingDistortion 196
7.1.2 HardClipping 196
7.2 DistortionFunctions 200
7.2.1 SoftClippingDistortion 200
7.2.2 OtherDistortionTransferFunctions 208
7.2.3 ControllingDistortionCharacter 208
7.3 DistortionofComplexSignals 213
7.4 DevelopingProcessesandLearningMore 216
Chapter8 AudioData Techniques .. ..... ...... ...... ...... .... 219
8.1 StoringandAccessingAudioData 220
8.1.1 StorageandProcessingRequirements 220
viii Contents
8.1.2 SimpleBuffering 221
8.1.3 ShiftRegistersandCircularBuffers 225
8.1.4 DelayedSound 232
8.1.5 PointerPositionConsiderations 235
8.2 SelectingandInterpolatingValues 237
8.2.1 Introduction 237
8.2.2 TruncationandRounding 239
8.2.3 LinearInterpolation 241
8.2.4 Non-linearInterpolation 242
8.3 LevelMeasurement 245
8.3.1 Introduction 245
8.3.2 AccuratePeakMeasurement 247
8.3.3 AccurateRMSMeasurement 249
8.3.4 Filter-BasedTechniques 252
8.3.5 RampingTechniques 255
8.3.6 SelectingandConfiguringEnvelopeFollowers 260
8.4 DevelopingProcessesandLearningMore 261
Chapter9 ModulatedModifiers . ...... ..... ...... ...... ...... . 265
9.1 Introduction 266
9.1.1 VariationoverTime 266
9.1.2 Oscillators 267
9.2 ExamplesofPeriodicModulation 270
9.2.1 TremoloandAutopan 270
9.2.2 FilterModulation 277
9.2.3 Vibrato 278
9.2.4 FlangerandPhaser 279
9.2.5 Chorus 283
9.2.6 ModulatedModulators 284
9.3 DevelopingProcessesandLearningMore 286
Chapter10 AcousticEnvironment ..... ..... ...... ...... ...... . 289
10.1 BasicConcepts 290
10.1.1 TypesofEnvironmentalEffects 290
10.1.2 FundamentalsofSoundinEnclosedSpaces 291
10.1.3 PracticalEnclosedSpaces 294
10.2 Non-RecirculatingEchoandReverberationForms 297
10.2.1 ASimpleModel 297
10.2.2 EchoEffects 298
10.2.3 MultitapImplementation 303
10.2.4 ImprovementstoEchoEffects 307
10.2.5 ReverberationEffects 309
10.2.6 ConvolutionwithImpulseResponses 310
10.3 RecirculatingEchoForms 313
10.3.1 BasicConcepts 313
10.3.2 EchoEffects 315
Contents ix
10.3.3 ImprovementstoEchoEffects 322
10.4 RecirculatingReverberationForms 323
10.4.1 BasicConcepts 323
10.4.2 ReverberatorwithCombandAllpassFilters 324
10.4.3 Multi-StageReverberator 326
10.4.4 ImprovementstotheMulti-StageReverberator 331
10.4.5 StereoReverberation 333
10.5 DevelopingProcessesandLearningMore 335
Chapter11 DynamicsProcesses .... ..... ...... ...... ...... .... 337
11.1 Introduction 338
11.1.1 ManualandAutomatedControlLoops 338
11.1.2 AmplitudeDynamics 339
11.1.3 BasicForms 340
11.2 NoiseGates 341
11.2.1 MainPrinciples 341
11.2.2 SimpleForm 345
11.2.3 ImprovementstotheSimpleForm 347
11.2.4 AdditionalTechniques 351
11.3 Compressors 353
11.3.1 MainPrinciples 353
11.3.2 CompressorForm 359
11.4 FurtherTechniques 362
11.4.1 Expanders 362
11.4.2 SidechainFiltering 364
11.4.3 Combinations 365
11.4.4 OtherModifications 366
11.5 DevelopingProcessesandLearningMore 367
Chapter12 FrequencyDomainMethods . ...... ...... ...... .... 369
12.1 TimeDomainandFrequencyDomainProcesses 370
12.1.1 Introduction 370
12.1.2 FourierTransformBasics 371
12.2 GeneralTechniques 377
12.2.1 Filtering 377
12.2.2 VocodingandApplicationofSpectralEnvelopes 379
12.2.3 Delay 381
12.3 MoreSophisticatedTechniques 382
12.3.1 Time-Stretching 383
12.3.2 ChangingPitch 383
12.3.3 ModifyingAmplitudeandFrequencyRelationships 387
12.3.4 BlendingandMorphing 389
12.4 DevelopingProcessesandLearningMore 390