Hack Audio: An Introduction to Computer Programming and Digital Signal Processing in MATLAB

493 Pages·2018·61.3 MB·English

by  Eric Tarr

Hack_Audio_7542_C000 2018/6/5 14:15 Page i #1
Hack Audio
An Introduction to Computer Programming and
Ⓡ
Digital Signal Processing in MATLAB
Computersareatthecenterofalmosteverythingrelatedtoaudio.Whetherforsynthesisin
musicproduction,recordinginthestudio,ormixinginlivesound,thecomputerplaysan
essentialpart.Audioeffectsplug-insandvirtualinstrumentsareimplementedassoftware
computercode.Musicappsarecomputerprogramsrunonamobiledevice.Allthesetoolsare
createdbyprogrammingacomputer.
HackAudio:AnIntroductiontoComputerProgrammingandDigitalSignalProcessingin
MATLABprovidesanintroductionformusiciansandaudioengineersinterestedincomputer
programming.Itisintendedforarangeofreadersincludingthosewithyearsofprogramming
experienceandthosereadytowritetheirfirstlineofcode.Inthebook,computer
programmingisusedtocreateaudioeffectsusingdigitalsignalprocessing.Bytheendofthe
book,readersimplementthefollowingeffects:signalgainchange,digitalsumming,tremolo,
auto-pan,mid/sideprocessing,stereowidening,distortion,echo,filtering,equalization,
multi-bandprocessing,vibrato,chorus,flanger,phaser,pitchshifter,auto-wah,convolution
andalgorithmicreverb,vocoder,transientdesigner,compressor,expander,andde-esser.
Throughoutthebook,severaltypesoftestsignalsaresynthesized,includingsinewave,square
wave,sawtoothwave,trianglewave,impulsetrain,whitenoise,andpinknoise.Common
visualizationsforsignalsandaudioeffectsarecreatedincludingwaveform,characteristic
curve,goniometer,impulseresponse,stepresponse,frequencyspectrum,andspectrogram.In
total,over200examplesareprovidedwithcompletedcodedemonstrations.
EricTarrisanassistantprofessorofAudioEngineeringTechnologyatBelmontUniversityin
Nashville,TN.Heteachesclassesondigitalaudio,computerprogramming,andsignal
processing.HereceivedaPh.D.,M.S.,andB.S.inElectricalandComputerEngineeringfrom
theOhioStateUniversity.HereceivedaB.A.inMathematicsandaminorinMusicfrom
CapitalUniversityinColumbus,OH.Hisworkhasspannedacrossthetopicsofspeechsignal
processing,musicalrobotics,soundspatialization,acousticandelectronicsystemmodeling,
hearingloss,perception,andcognition.HehaspublishedarticlesintheJournalofthe
AcousticalSocietyofAmerica,JournalofSpeech,Language,andHearingResearch,
InternationalJournalofAudiology,andMechanicalEngineeringResearch.Heisamember
oftheAudioEngineeringSociety.In2015,Dr.TarrreceivedtheGibsonFoundationLesPaul
MusicInnovationAwardastheprincipalinvestigatorofaresearchgranton“Blockchain
TechnologyintheMusicIndustry.”
Hack_Audio_7542_C000 2018/6/5 14:15 Page ii #2
AUDIOENGINEERINGSOCIETYPRESENTS…
http://www.aes.org/
EditorialBoard
Chair:FrancisRumsey,LogophonLtd.
HyunKookLee,UniversityofHuddersfield
NatanyaFord,UniversityofWestEngland
KyleSnyder,OhioUniversity
OthertitlesintheSeries:
HandbookforSoundEngineers,5thEdition
EditedbyGlenBallou
AudioProductionandCriticalListening,2ndEdition
AuthoredbyJasonCorey
RecordingOrchestraandOtherClassicalMusicEnsembles
AuthoredbyRichardKing
RecordingStudioDesign,4thEdition
AuthoredbyPhilipNewell
ModernRecordingTechniques,9thEdition
AuthoredbyDavidMilesHuber
ImmersiveSound:TheArtandScienceofBinauralandMulti-ChannelAudio
EditedbyAgnieszkaRoginskaandPaulGeluso
HackAudio:AnIntroductiontoComputerProgrammingandDigitalSignal
ProcessinginMATLABⓇ
AuthoredbyEricTarr
Hack_Audio_7542_C000 2018/6/5 14:15 Page iii #3
Hack Audio
An Introduction to Computer Programming and
Ⓡ
Digital Signal Processing in MATLAB
Eric Tarr
Hack_Audio_7542_C000 2018/6/5 14:15 Page iv #4
Firstpublished2019
byRoutledge
711ThirdAvenue,NewYork,NY10017
andbyRoutledge
2ParkSquare,MiltonPark,Abingdon,Oxon,OX144RN
RoutledgeisanimprintoftheTaylor&FrancisGroup,aninformabusiness
©2019Taylor&Francis
TherightofEricTarrtobeidentifiedasauthorofthisworkhasbeenassertedbyhiminaccordancewithsections77and78of
theCopyright,DesignsandPatentsAct1988.
Allrightsreserved.Nopartofthisbookmaybereprintedorreproducedorutilisedinanyformorbyanyelectronic,mechanical,
orothermeans,nowknownorhereafterinvented,includingphotocopyingandrecording,orinanyinformationstorageor
retrievalsystem,withoutpermissioninwritingfromthepublishers.
ReprintwithpermissionofTheMathWorks,Inc.
MATLAB®andSimulink®areregisteredtrademarksofTheMathWorks,Inc.andareusedwithpermission.TheMathWorks
doesnotwarranttheaccuracyofthetextorexercisesinthisbook.Thisbook’suseordiscussionofMATLAB®andSimulink®
softwareorrelatedproductsdoesnotconstituteendorsementorsponsorshipbytheMathWorksofaparticularpedagogical
approachorparticularuseoftheMATLAB®andSimulink®software.
ForMATLABandSimulinkproductinformation,pleasecontact:
TheMathWorks,Inc.
3AppleHillDrive
Natick,MA01760-2098USA
Tel:[phone]
Fax:[phone]
E-mail:[email protected]
Web:mathworks.com
Howtobuy:www.mathworks.com/store
Trademarknotice:Productorcorporatenamesmaybetrademarksorregisteredtrademarks,andareusedonlyforidentification
andexplanationwithoutintenttoinfringe.
LibraryofCongressCataloging-in-PublicationData
Names:Tarr,Eric,author.
Title:Hackaudio:anintroductiontocomputerprogramminganddigitalsignalprocessing
inMATLAB/EricTarr.
Description:NewYork,NY:Routledge,2019.|Series:AudioEngineeringSocietypresents
Identifiers:LCCN2018006035|ISBN9781138497542(hardback:alk.paper)|
ISBN9781138497559(pbk.:alk.paper)|ISBN781351018463(ebook)
Subjects:LCSH:MATLAB.|Computersoundprocessing.
Classification:LCCML74.4.M36T372018|DDC006.5–dc23
LCrecordavailableathttps://lccn.loc.gov/2018006035
ISBN:978-1-138-49754-2(hbk)
ISBN:978-1-138-49755-9(pbk)
ISBN:978-1-351-01846-3(ebk)
TypesetinTimes
bydiacriTech
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Dedicated to
my supportive wife,Kate
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Contents
List of Tables..............................................................................................xvii
List of Figures.............................................................................................xix
List of Examples ......................................................................................xxvii
Acknowledgements................................................................................xxxiii
Chapter 1: Introduction................................................................................1
1.1 Introduction:ComputerProgrammingandDigitalSignalProcessing .............1
1.2 ThePurposeofThisBook............................................................1
1.3 IntendedReaders......................................................................1
1.4 TopicsCovered........................................................................2
1.5 AdditionalContent....................................................................2
Chapter 2: Basics of Programming in MATLABⓇ ........................................3
2.1 Introduction:ComputerProgramminginMATLAB................................3
2.2 ProgrammingLanguages.............................................................3
2.3 ExecutedCommands .................................................................4
2.3.1 ErrorStatements.............................................................4
2.4 Mathematics...........................................................................4
2.4.1 Operators.....................................................................4
2.4.2 Variables .....................................................................6
2.5 DataTypes ............................................................................8
2.5.1 Numbers......................................................................8
2.5.2 Characters....................................................................9
2.5.3 Strings........................................................................9
2.6 Arrays ................................................................................10
2.6.1 BasicArrayCreation .......................................................10
2.6.2 PlottingArrays..............................................................11
2.7 MathematicalFunctions.............................................................12
2.7.1 PlottingMathematicalFunctions ..........................................12
vii
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viii Contents
2.8 APPENDIX:AdditionalPlottingOptions..........................................12
2.8.1 LineSpecification ..........................................................12
2.8.2 AxisLabels .................................................................15
2.8.3 FigureTitle..................................................................15
2.8.4 FigureLegend ..............................................................15
2.8.5 AxisScale...................................................................15
2.8.6 AxisDimensions............................................................16
2.8.7 MultipleArrays.............................................................17
Chapter 3: Basics of Audio in MATLABⓇ ...................................................21
3.1 Introduction:DigitalAudioSignals.................................................21
3.2 MATLABAudioFunctions .........................................................22
3.2.1 audioread .................................................................22
3.2.2 sound .......................................................................22
3.2.3 audiowrite................................................................23
3.2.4 audioinfo .................................................................23
3.3 WorkingwithAudioSignalsinArrays .............................................23
3.3.1 IndexingArrays.............................................................23
3.3.2 ArrayReversal..............................................................26
3.3.3 AdditionalMethodstoCreateArrays .....................................26
3.3.4 ArrayTransposition ........................................................28
3.3.5 DeterminingDimensionsofArrays........................................28
3.4 VisualizingtheWaveformofanAudioSignal .....................................29
Bibliography ..............................................................................30
Chapter 4: MATLABⓇ Programming Environment...................................31
4.1 Introduction:MATLABApplication................................................31
4.1.1 CommandWindow.........................................................31
4.1.2 Workspace ..................................................................33
4.1.3 CurrentFolder ..............................................................34
4.2 MATLABm-Files ...................................................................34
4.2.1 Scripts.......................................................................35
4.2.2 CommentingCode..........................................................36
4.3 MATLABDebuggingMode ........................................................36
4.4 MATLABHelpDocumentation.....................................................38
Chapter 5: Logicals and Control Structures in Programming..................41
5.1 Introduction:ControllingtheFlowofExecution...................................41
5.2 LogicalDataType ...................................................................41
5.2.1 LogicalOperations .........................................................41
5.2.2 CombiningLogicalOperators .............................................43
5.2.3 StringCompare.............................................................44
5.3 TypesofControlStructures .........................................................44
5.3.1 ConditionalStatements.....................................................44
5.3.2 Loops........................................................................47
5.3.3 Functions....................................................................52
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Contents ix
Chapter 6: Signal Gain and DC Offset.......................................................57
6.1 Introduction:DigitalSignalProcessing.............................................57
6.1.1 Element-WiseProcessing ..................................................57
6.1.2 Element-WiseReferencing.................................................57
6.1.3 BlockDiagrams.............................................................58
6.2 ScalarOperationswithArrays ......................................................59
6.2.1 ScalarMultiplication:ConvertingTimeUnits ............................60
6.3 ScalarMultiplication:SignalGain..................................................61
6.3.1 SignalGainBlockDiagram................................................61
6.3.2 PolarityInversion...........................................................63
6.3.3 DecibelScale ...............................................................64
6.4 VisualizingtheAmplitudeChange..................................................66
6.4.1 InputversusOutputCharacteristicCurve .................................66
6.5 ScalarAddition:DCOffset..........................................................68
6.5.1 DCOffsetBlockDiagram..................................................68
6.6 CombinedSignalGainandDCOffset..............................................71
6.7 AmplitudeMeasurements ...........................................................72
6.7.1 SignalPeakAmplitude.....................................................73
6.7.2 Peak-to-PeakAmplitude ...................................................73
6.7.3 Root-Mean-SquareAmplitude.............................................74
6.7.4 DynamicRangeCrestFactor ..............................................75
6.8 AmplitudeNormalization ...........................................................76
6.8.1 PeakNormalization.........................................................76
6.8.2 Root-Mean-SquareNormalization.........................................77
Bibliography ..............................................................................78
Chapter 7: Introduction to Signal Synthesis..............................................79
7.1 Introduction:SignalSynthesis ......................................................79
7.2 VisualizingtheFrequencySpectrumofanAudioSignal..........................79
7.3 PeriodicSignals......................................................................80
7.3.1 SineWave...................................................................80
7.3.2 CosineFunction ............................................................86
7.3.3 SquareWave ................................................................87
7.3.4 SawtoothWave .............................................................91
7.3.5 TriangleWave...............................................................93
7.3.6 ImpulseTrain ...............................................................96
7.4 AperiodicSignals....................................................................99
7.4.1 WhiteNoise.................................................................99
Bibliography ............................................................................ 101
Chapter 8: Digital Summing,Signal Fades,and Amplitude
Modulation..............................................................................103
8.1 Introduction:CombiningSignals ................................................. 103
8.1.1 ArrayOperationswithArrays............................................ 103
8.1.2 UsingArrayOperationstoCombineSignals............................ 104