Building acoustics

472 Pages·2008·6.23 MB·English

Acoustics

Acoustics
An introduction
Heinrich Kuttruff
Germaneditionfirstpublished2004
byS.HirzelVerlag
Englisheditionpublished2007
byTaylor&Francis
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byTaylor&Francis
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ISBN 0-203-97089-6 Master e-book ISBN
ISBN10:0–415–38679–9ISBN13:978–0–415–38679–1(hbk)
ISBN10:0–415–38680–2 ISBN13:978–0–415–38680–7(pbk)
ISBN10:0–203–97089–6ISBN13:978–0–203–97089–8(ebk)
Contents
Listofsymbols xi
1 Introduction 1
1.1 Whatissound? 2
1.2 Whatisacoustics? 4
2 Somefactsonmechanicalvibrations 7
2.1 Afewexamples 7
2.2 Complexnotationofharmonicvibrations 11
2.3 Beats 12
2.4 Forcedvibrations,impedance 13
2.5 Resonance 14
2.6 Freevibrationsofasimpleresonator 18
2.7 Electromechanicalanalogies 19
2.8 Power 22
2.9 Fourieranalysis 23
2.10 Transferfunctionandimpulseresponse 29
2.11 Anoteonnon-linearsystems 32
3 Acousticvariablesandbasicrelations 34
3.1 Acousticvariables 34
3.2 Basicrelationsinacoustics 37
3.3 Waveequations 42
3.4 Intensityandenergydensityofsoundwaves
influids 44
3.5 Thesoundpressurelevel 47
vi Contents
4 Planewaves,attenuation 48
4.1 Solutionofthewaveequation 48
4.2 Harmonicwaves 51
4.3 Afewnotesonsoundvelocity 54
4.4 Attenuationofsound 55
4.5 Non-lineareffects 65
5 Sphericalwaveandsoundradiation 69
5.1 Solutionofthewaveequation 69
5.2 Thepointsource 71
5.3 TheDopplereffect 74
5.4 Directionalfactorandradiationresistance 76
5.5 Thedipole 79
5.6 Thelineararray 81
5.7 Thesphericalsource 84
5.8 Pistoninaplaneboundary 86
6 Reflectionandrefraction 94
6.1 Anglesofreflectionandrefraction 94
6.2 Soundpropagationintheatmosphere 96
6.3 Reflectionfactorandwallimpedance 98
6.4 Absorptioncoefficient 103
6.5 Standingwaves 104
6.6 Soundabsorptionbywallsandlinings 106
7 Diffractionandscattering 118
7.1 Exactformulationofdiffractionproblems 120
7.2 Diffractionbyarigidsphere 121
7.3 Soundtransmissionthroughapertures 124
7.4 Babinet’sprinciple 132
7.5 Multiplescattering,scatteringfromroughsurfaces 134
8 Soundtransmissioninpipesandhorns 138
8.1 Soundattenuationinpipes 138
8.2 Basicrelationsfortransmissionlines 141
8.3 Pipeswithdiscontinuitiesincrosssection 143
8.4 Pipeswithcontinuouslychangingcross
section(horns) 150
Contents vii
8.5 Higherorderwavetypes 156
8.6 Dispersion 162
9 Soundinclosedspaces 166
9.1 Normalmodesinaone-dimensionalspace 166
9.2 Normalmodesinarectangularroomwith
rigidwalls 169
9.3 Normalmodesincylindricalandspherical
cavities 173
9.4 Forcedvibrationsinaone-dimensional
enclosure 174
9.5 Forcedvibrationsinenclosuresofanyshape 178
9.6 Freevibrations 182
9.7 Statisticalpropertiesofthetransferfunction 185
10 Soundwavesinisotropicsolids 189
10.1 Soundwavesinunboundedsolids 189
10.2 Reflectionandrefraction,Rayleighwave 194
10.3 Wavesinplatesandbars 197
11 Musicandspeech 209
11.1 Simpleandcomplextones,noise 209
11.2 Pitch,intervalsandscales 211
11.3 Generalremarkonthefunctionofmusical
instruments 214
11.4 Stringinstruments 215
11.5 Windinstruments 223
11.6 Thehumanvoice 228
12 Humanhearing 233
12.1 Anatomyandfunctionoftheear 234
12.2 Psychoacousticpitch 239
12.3 Hearingthresholdandauditorysensationarea 243
12.4 Loudnesslevelandloudness,critical
frequencybands 244
12.5 Auditorymasking 248
12.6 Measurementofloudness 249
12.7 Spatialhearing 252
viii Contents
13 Roomacoustics 257
13.1 Geometricroomacoustics 258
13.2 Impulseresponseofaroom 261
13.3 Diffusesoundfield 264
13.4 Steady-stateenergydensityandreverberation 268
13.5 Soundabsorption 271
13.6 Onthe‘acoustics’ofauditoria 277
13.7 Specialroomsforacousticmeasurements 280
14 Buildingacoustics 283
14.1 Characterisationandmeasurementofairbornesound
insulation 284
14.2 Airbornesoundinsulationofcompound
partitions 287
14.3 Airbornesoundinsulationofsingle-leaf
partitions 289
14.4 Airbornesoundinsulationofdouble-leaf
partitions 296
14.5 Structure-bornesoundinsulation 301
15 Fundamentalsofnoisecontrol 309
15.1 Noisecriteria 310
15.2 Basicmechanismsofnoisegeneration 311
15.3 Primarynoisecontrol 316
15.4 Secondarynoisecontrol 320
15.5 Personalhearingprotection 331
16 Underwatersoundandultrasound 333
16.1 Acousticaldetectionandlocalisationofobjects 333
16.2 Soundpropagationinseawater 335
16.3 Strengthofechoes 337
16.4 Ambientnoise,reverberation 338
16.5 Transducerarrays 340
16.6 Generalremarksonultrasound 342
16.7 Generationanddetectionofultrasound 343
16.8 Diagnosticapplicationsofultrasound 345
16.9 Applicationsofhighintensityultrasound 349
16.10 Generationofhighandhighestultrasound
frequencies 353
Contents ix
17 Electroacoustictransducers 359
17.1 Piezoelectrictransducer 361
17.2 Electrostatictransducer 365
17.3 Dynamictransducer 368
17.4 Magnetictransducer 371
17.5 Magnetostrictivetransducer 373
17.6 Thecouplingfactor 375
17.7 Two-portequationsandreciprocityrelations 377
18 Microphones 379
18.1 Principlesofmicrophonesforairbornesound 379
18.2 Condensormicrophone 382
18.3 Piezoelectricmicrophones 387
18.4 Dynamicmicrophones 389
18.5 Carbonmicrophone 391
18.6 Microphonedirectivity 392
18.7 Hydrophones 396
18.8 Vibrationpickups 396
18.9 Microphonecalibration 399
19 Loudspeakersandotherelectroacousticsoundsources 403
19.1 Dynamicloudspeaker 405
19.2 Electrostaticorcondensorloudspeaker 408
19.3 Magneticloudspeaker 410
19.4 Improvementofloudspeakerefficiency 411
19.5 Loudspeakerdirectivity 417
19.6 Earphones 419
19.7 Soundtransmittersforwater-bornesoundandfor
ultrasound 421
20 Electroacousticsystems 426
20.1 Stereophony 427
20.2 Soundrecording 433
20.3 Soundreinforcementsystems 443
Literature 451
Index 453