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1 Chapter 1Figure 1.1 Examples of different types of signals and their spectral content...Figure 1.2 Time and frequency domain representations of (a) pure tone; (b) c...Figure 1.3 Periodic sound signal.Figure 1.4 Frequency spectrum of the periodic signal of Figure 1.3.Figure 1.5 Random noise signal.Figure 1.6 Time and frequency domain representations of the transient respon...Figure 1.7 Time and frequency domain representations of the transient respon...Figure 1.8 Power spectral density of random noise.Figure 1.9 Different types of filter. Low‐pass, high‐pass, band‐pass, and ba...Figure 1.10 Typical frequency response of a filter of center frequency fC an...Figure 1.11 Comparison between bandwidths of (a) constant percentage and (b)...Figure 1.12 Simplified block diagram of a parallel‐filter real‐time analyzer...Figure 1.13 Conversion from FFT spectra to a constant percentage bandwidth (

2 Chapter 2Figure 2.1 Representation of simple harmonic motion by projection of the rot...Figure 2.2 Simple harmonic motion.Figure 2.3 Simple harmonic motion with initial phase angle ϕ.Figure 2.4 Displacement, velocity, and acceleration.Figure 2.5 Movement of mass on a spring: (a) static deflection due to gravit...Figure 2.6 Movement of damped simple system.Figure 2.7 Motion of a damped mass–spring system, R < (4MK)1/2.Figure 2.8 Forced vibration of damped simple system.Figure 2.9 Dynamic magnification factor (DMF) for a damped simple system.Figure 2.10 Force transmissibility, TF, for a damped simple system.Figure 2.11 Two‐degree‐of‐freedom system.Figure 2.12 Mode shapes for the two‐degree of freedom system shown in Figure...Figure 2.13 Harmonically forced two‐degree‐of‐freedom system.Figure 2.14 Forced response spectra of a damped two‐degree of freedom system...Figure 2.15 Undamped dynamic vibration absorber defined in Example 2.9.Figure 2.16 First four mode shapes of a cantilever beam.Figure 2.17 Velocity level of a fully‐clamped rectangular plate as a functio...Figure 2.18 First six modes of a rectangular plate.Figure 2.19 Computed velocity level of a simply‐supported rectangular plate ...

3 Chapter 3Figure 3.1 Schematic illustration of the sound pressure distribution created...Figure 3.2 Plane waves of arbitrary waveform.Figure 3.3 Simple harmonic plane waves.Figure 3.4 Some typical sound pressure levels, Lp.Figure 3.5 Some typical sound power levels, LW.Figure 3.6 Diagram for combination of two sound pressure levels or two sound...Figure 3.7 Imaginary surface area S for integration.Figure 3.8 Sound intensity In, being measured on (a) segment dS of an imagin...Figure 3.9 Sound intensity probe microphone arrangement commonly used.Figure 3.10 Source above a rigid surface.Figure 3.11 Polar directivity plots for the radial sound intensity in the fa...Figure 3.12 Geometry used in derivation of directivity factor.Figure 3.13 Incident intensity Ii, reflected intensity Ir, and transmitted i...Figure 3.14 Refraction of sound in air with wind speed U(h) increasing with ...Figure 3.15 Refraction of sound in air with normal temperature lapse (temper...Figure 3.16 Refraction of sound in air with temperature inversion.Figure 3.17 Example of monopole. On the monopole surface, velocity of surfac...Figure 3.18 Sound pressure level in an interior sound field.Figure 3.19 Sound absorption coefficient α of typical absorbing materia...Figure 3.20 Measurement of reverberation time TR.Figure 3.21 Examples of recommended reverberation times.Figure 3.22 Sound source in anechoic room.Figure 3.23 Sound pressure level in a room (relative to sound power level) a...Figure 3.24 Dependence on frequency of bending‐wave speed cb on a beam or pa...Figure 3.25 Variation with frequency of bending wavelength λb on a beam...Figure 3.26 Diagram showing trace wave matching between waves in air of wave...Figure 3.27 Wavelength relations and effective radiating areas for corner, e...Figure 3.28 Comparison of theoretical and measured radiation ratios σ f...Figure 3.29 Measured radiation ratios of unstiffened and stiffened plates fo...Figure 3.30 Waves on a string: (a) Two opposite and equal traveling waves on...Figure 3.31 Sound waves in a tube. First mode standing wave for sound pressu...Figure 3.32 Direction cosines and vector k.Figure 3.33 Wave vectors for eight propagating waves.Figure 3.34 Standing wave for nx = 1, ny = 1, and nz = 1 (particle velocity ...Figure 3.35 Standing wave for nx = 1, ny = 1, and nz = 1 (sound pressure sho...

4 Chapter 4Figure 4.1 Simplified cross‐section through the human ear.Figure 4.2 Tympanic membrane (eardrum) and three auditory ossicles.Figure 4.3 Section through the cochlea and details of the organ of Corti.Figure 4.4 Cochlea “unwrapped” to show working of the ear schematically.Figure 4.5 Human auditory field envelope.Figure 4.6 Equal loudness contours. The contours join the sound pressure lev...Figure 4.7 Relationship between the loudness (in sones) and the loudness lev...Figure 4.8 Contours of equal loudness index.Figure 4.9 Contours joining sound pressure levels of pure tones at different...Figure 4.10 Masking of tones by noise at different frequencies and sound pre...Figure 4.11 Masking effect of a narrow‐band noise of bandwidth 160 Hz center...Figure 4.12 Postmasking at different masker sound pressure levels [17].Figure 4.13 Postmasking of 5‐ms, 2‐kHz tones preceded by bursts of uniform m...Figure 4.14 A‐, B‐, and C‐weighting filter characteristics used with sound l...Figure 4.15 Relation between subjective response and A‐weighted sound pressu...Figure 4.16 Loudness level in phons of a band of filtered white noise center...Figure 4.17 Dependence of loudness level LN (left ordinate) on duration Ti o...Figure 4.18 Critical bandwidth, critical ratio, and equivalent rectangular b...Figure 4.19 Relations between bark scale and frequency scale [17, 18].Figure 4.20 Masking patterns [17, 18] of narrow‐band noises centered at diff...Figure 4.21 Schematic illustration of Zwicker's loudness model [17, 18].Figure 4.22 Illustration of temporal effects in loudness processing [17, 18]...Figure 4.23 Block diagram of a dynamic loudness meter (DLM) [46].Figure 4.24 Shift in hearing threshold at different frequencies against age ...Figure 4.25 Sectional view of the head showing the important elements of the...Figure 4.26 Directivity patterns for the human voice in a horizontal plane....Figure 4.27 Directivity patterns for the human voice in a vertical plane....

5 Chapter 5Figure 5.1 Differences in percentages of occurrence of various physiological...Figure 5.2 Incidence of hypertensive men and women workers (above and below ...Figure 5.3 Relative risks (odds ratio) for myocardial infarction due to road...Figure 5.4 Electron microscope image of the hair cells in the cochlea (a) ha...Figure 5.5 Schematic representation of the two basic impulse noise pressure–...Figure 5.6 Comparison of duration per day for allowable A‐weighted noise exp...Figure 5.7 Four basic types of hearing protector devices (HPDs).Figure 5.8 Mechanical model of the human body showing resonance frequency ra...Figure 5.9 Reiher‐Meister chart of human response to vertical vibrations [45...Figure 5.10 Acceleration frequency weightings for whole‐body vibration and m...Figure 5.11 Acceleration frequency weighting Wh for the evaluation of hand‐t...

6 Chapter 6Figure 6.1 The bottom curves (marked Hearing Threshold) show the absolute th...Figure 6.2 Contours of perceived noisiness.Figure 6.3 Typical noise history of a fanjet aircraft flyover [13].Figure 6.4 How tone‐corrected perceived noise level may vary in an aircraft ...Figure 6.5 Talker‐to‐listener distances (m) for male speech communication to...Figure 6.6 Comprehensive diagram summarizing speech levels for communication...Figure 6.7 Noise criterion (NC) curves.Figure 6.8 Noise rating (NR) curves.Figure 6.9 Room criterion (RC) curves.Figure 6.10 Balanced noise criterion (NCB) curves.Figure 6.11 Equivalent sound pressure level.Figure 6.12 (a) Percentile levels and (b) cumulative probability distributio...Figure 6.13 A‐weighted sound pressure levels measured in 1971 at 18 location...Figure 6.14 Annoyance as a function of noise level.Figure 6.15 Variation of percentile levels throughout 24 hours periods recor...Figure 6.16 Proposed sleep disturbance curve based on data of Pearsons et al...Figure 6.17 Curves representing the percentage of subjects that are highly a...Figure 6.18 Curves representing the percentage of subjects that are highly a...Figure 6.19 Curves representing the percentage of subjects that are highly a...Figure 6.20 Scale of vibration discomfort from British Standard 6841 and Int...Figure 6.21 Response of building in good condition to vibration (*Rendering ...

7 Chapter 7Figure 7.1 Idealized noise or vibration‐measuring system.Figure 7.2 Sensitivity of (i) an ideal microphone or accelerometer ______ an...Figure 7.3 Sensitivity of an ideal microphone or accelerometer showing upper...Figure 7.4 Inherent noise floor against upper limiting sound pressure level ...Figure 7.5 Comparison of the dynamic ranges of the same four condenser micro...Figure 7.6 Frequency response of an ideal microphone or accelerometer.Figure 7.7 Comparison of the frequency response ranges of four different dia...Figure 7.8 Cross‐section through a 1‐in. condenser microphone.Figure 7.9 Electret microphone using a thin electret polymer layer deposited...Figure 7.10 Cross‐sectional view of piezoelectric microphone.Figure 7.11 Directivity of a microphone with a protection grid at different ...Figure 7.12 Noise measurements using (a) free‐field microphone and (b) diffu...Figure 7.13 Idealized diagram of vibration transducer.Figure 7.14 Transverse and longitudinal sensitivity of accelerometer.Figure 7.15 Mounting of an accelerometer to reduce cable whip noise.Figure 7.16 Effect of mass loading of an accelerometer on the vibration of a...

8 Chapter 8Figure 8.1 Tyndall's flames [2]. A long flame may be shortened and a short o...Figure 8.2 Tyndall's smoke jets [2]. The amount of shrinkage exhibited by so...Figure 8.3 Rayleigh's copy of Mayer's paper on sound intensity.Figure 8.4 (a) Arrangement of apparatus for wave calibration by means of the...Figure 8.5 Instantaneous spatial distributions of sound pressure, particle v...Figure 8.6 Sound energy and sound intensity.Figure 8.7 Spatial distributions of instantaneous sound pressure, instantane...Figure 8.8 Idealized monopole source of sound.Figure 8.9 (a) Real intensity fluctuations, (b) Imaginary intensity fluctuat...Figure 8.10 Schematic diagram of sound intensity measurements made with the ...Figure 8.11 Schematic diagram of sound intensity measurements made with the ...Figure 8.12 Microphones arrangements used to measure sound intensity.Figure 8.13 Sound intensity probe with the microphones in the face‐to‐face c...Figure 8.14 Three‐dimensional sound intensity probe for vector measurements;...Figure 8.15 Experimental set‐up for measuring sound intensity, (a) near fiel...Figure 8.16 Illustration of the error due to the finite difference approxima...Figure 8.17 Finite difference error of an ideal p–p face‐to‐face sound...Figure 8.18 Pressure increase on the two microphones of a sound intensity pr...Figure 8.19 Error of a p–p sound intensity probe with half‐inch microp...Figure 8.20 Error level Le due to a phase error φe of 0.3° in a plane p...Figure 8.21 Coupler for measurement of the pressure‐residual intensity index...Figure 8.22 Maximum error due to a phase mismatch as a function of the bias ...Figure 8.23 The global pressure‐intensity index ∆pl determined under three d...Figure 8.24 Effective separation results performed by the manufacturer of th...Figure 8.25 Calibrators for calibration of sound intensity calibration in th...Figure 8.26 Sensitivity and gain adjustment using B&K calibrator 3541Figure 8.27 Phase difference determination between microphone pair using B...Figure 8.28 Use of B&K coupler UA 0914 and calibrator B&K 3541 to verify pha...Figure 8.29 Final verification steps in system calibration using free field ...Figure 8.30 Final verification check to see that the sound pressure level (F...Figure 8.31 Normalized systematic error ϕe of a p–u system due to...Figure 8.32 A p–u sound intensity probe.Figure 8.33 Hand‐held probe for surface intensity measurement [84].Figure 8.34 Phase shift Δϕx from the finite distance between the microp...Figure 8.35 Transducer arrangement for phase shift determination [82].Figure 8.36 Error E in intensity caused by uncorrected phase shift ϕ [8...Figure 8.37 Sound intensity measured on a segment of (a) a hemispherical mea...Figure 8.38 Typical box surface used in sound power determination with the i...Figure 8.39 Sound power level measured by sound intensity of a Caterpillar T...Figure 8.40 Indoor sound power measurement of a reciprocating compressor [90...Figure 8.41 Automated sound‐intensity system used to measure the sound power...Figure 8.42 Garden tractor used for tests of gated sound power [91].Figure 8.43 Measurements of the sound intensity radiated by a vacuum cleaner...Figure 8.44 Sound intensity vectors measured in two planes near a violoncell...Figure 8.45 Oil pan narrow‐band sound power level spectrum determined from t...Figure 8.46 Comparison of sound power level determined for the oil pan from ...Figure 8.47 Narrow‐band sound power level determined from surface intensity ...Figure 8.48 Comparison of sound power level determined for the oil pan from ...Figure 8.49 Radiation efficiency of the oil pan determined at an engine spee...Figure 8.50 Comparison of diffuse field intensities averaged over narrow fre...Figure 8.51 Experimental set‐up for measurement of transmission loss of a pa...Figure 8.52 Transmission loss of a 3.2 mm thick aluminum panel: ‐‐□‐‐...Figure 8.53 Measured and calculated transmission loss of a composite aluminu...Figure 8.54 The transmitted sound intensity measured with a probe with micro...Figure 8.55 Interlaboratory comparisons according to ISO 140‐3 for a single ...Figure 8.56 Interlaboratory comparison for a single metal leaf window (lower...Figure 8.57 Photograph of the aircraft fuselage in the semi‐anechoic chamber...Figure 8.58 Instrumentation used for the measurement of sound transmission l...Figure 8.59 Transmission loss versus frequency for the back passenger window...Figure 8.60 Sound transmission loss versus frequency for different aircraft ...Figure 8.61 Schematic diagram of the experimental set‐up for the measurement...Figure 8.62 Transmission loss of the cylindrical shell measured by two‐micro...Figure 8.63 Experimental results of radiation efficiency at one‐third octave...Figure 8.64 Layout of the packaging machine [101].Figure 8.65 Sound intensity measurement set‐up.Figure 8.66 Sound pressure measurement set‐up [101].Figure 8.67 Convergence of sound power results [101].Figure 8.68 Signal/noise ratio [101].Figure 8.69 Sound power level (SIL) results from sound intensity method. Sou...Figure 8.70 Comparison of final fixed points and scanning values, final fixe...

9 Chapter 9Figure 9.1 Source‐path‐receiver model for noise and vibration problems.Figure 9.2 Sources and paths of airborne and structure‐borne noise and vibra...Figure 9.3 Source–path–receiver system showing airborne and structure‐borne ...Figure 9.4 Rigid machine of mass m attached to a rigid massive floor.Figure 9.5 Rigid machine of mass m separated from rigid massive floor by vib...Figure 9.6 Relationship between natural frequency fn of machine‐isolator‐flo...Figure 9.7 Relationship (for a linear isolator) between forcing frequency f,...Figure 9.8 Machine vibration severity chart showing peak‐to‐peak‐ vibration ...Figure 9.9 Typical ranges of material damping loss factors at small strains ...Figure 9.10 Different ways of using vibration damping materials: (a) free (u...Figure 9.11 Paths of direct and reflected sound emitted by a machine in a bu...Figure 9.12 The two main mechanisms believed to exist in sound‐absorbing mat...Figure 9.13 Typical absorption coefficient vs. octave band frequency charact...Figure 9.14 Sound absorption coefficient α and noise reduction coeffici...Figure 9.15 Effect on the sound absorption coefficient α of placing a 2...Figure 9.16 A Helmholtz resonator consists of a neck of radius r, length L a...Figure 9.17 Sound absorption coefficient vs. frequency for a slotted 20‐cm c...Figure 9.18 Slotted concrete blocks faced with fiberglass and covered with a...Figure 9.19 Geometry for a typical perforated panel absorber.Figure 9.20 Variable airspace perforated panels give broader absorption char...Figure 9.21 Porous absorbing material protected by a thin Mylar (polyester) ...Figure 9.22 Slat type of resonator absorber (normally the mineral wool is pl...Figure 9.23 Sound‐absorbing material placed on the walls and under the roof ...Figure 9.24 Sound absorption coefficient α of a 13‐mm thick acoustical ...Figure 9.25 Acoustical enclosure placed in free field.Figure 9.26 Personnel enclosure placed in a reverberant sound field.Figure 9.27 Machine enclosure placed in a reverberant environment.Figure 9.28 Close‐fitting enclosure attenuation in sound pressure level for ...Figure 9.29 Simplified one‐dimensional model for a close‐fitting enclosure [...Figure 9.30 Theoretical close‐fitting enclosure insertion loss performance [...Figure 9.31 Partial enclosure.Figure 9.32 Decrease of enclosure insertion loss, ΔIL, as a function of the ...Figure 9.33 Enclosures with penetrations (for cooling) lined with absorbing ...Figure 9.34 Basic elements of an acoustical enclosure used for machinery noi...Figure 9.35 Major components and cooling airflow of an air compressor [114]....Figure 9.36 Enclosure for a bandsaw.Figure 9.37 Ready‐made modular materials used to make enclosures and barrier...Figure 9.38 Sound waves reflected and diffracted by barrier and acoustical s...Figure 9.39 Attenuation of a barrier as a function of Fresnel number N for p...Figure 9.40 Freestanding barrier used indoors and the three diffraction path...Figure 9.41 Image method for reflections on the ground.Figure 9.42 Effect of multiple reflections on the acoustical performance of ...Figure 9.43 Elements of an active noise control system in a duct: (a) simple...Figure 9.44 Active headset in which the sound inside the headset is detected...Figure 9.45 Active noise control for fan noise reduction [146].Figure 9.46 Hybrid passive/active absorber cell [60].

10 Chapter 10Figure 10.1 Definitions of muffler performance.Figure 10.2 Typical straight‐through reactive mufflers: (a) single expansion...Figure 10.3 Cross‐section of typical U.S. automobile muffler with flow‐rever...Figure 10.4 Examples of common commercial automobile mufflers [13].Figure 10.5 Radiated sound pressure level error due to neglect of mean flow,...Figure 10.6 Influence of mean gas flow on effectiveness of silencer. ○, meas...Figure 10.7 Power reflection and phase angle for open end tube. Solid line: ...Figure 10.8 Measured values of transmission loss for prototype automotive mu...Figure 10.9 Muffler element.Figure 10.10 Expansion chamber with inlet pipe 1 and outlet pipe 3, both of ...Figure 10.11 Transmission loss TL of an expansion chamber of length l and S2Figure 10.12 Acoustical conditions at the side‐branch of input acoustical im...Figure 10.13 Electrical analogy of the side‐branch system shown in Figure 10...Figure 10.14 Helmholtz resonator with equivalent simple mechanical system.Figure 10.15 Calculated transmission loss of Helmholtz resonator in Example ...Figure 10.16 Quarter‐wave resonator as a side‐branch.Figure 10.17 Transmission loss for side‐branch quarter‐wave resonator in Exa...Figure 10.18 (a) Comparison of theoretical and experiment attenuation charac...Figure 10.19 Multiple‐expansion‐chamber mufflers. (a) Effect of connecting‐t...Figure 10.20 (a) Mufflers with internal connecting tubes equal in length to ...Figure 10.21 Effect of varying the conductivity c0 and the tube length of co...Figure 10.22 (a) Effect of conductivity c0 using connecting tubes. (b) Effec...Figure 10.23 Combination mufflers [21, 64].Figure 10.24 Four‐pole representation of muffler element.Figure 10.25 Series connection of transmission matrices.Figure 10.26 (a) Real engine‐muffler exhaust system; (b) Volume velocity ana...Figure 10.27 Reflection of sound. (a) exhaust tail pipe, Pr = R × P...Figure 10.28 (a) Volume velocity source; (b) Pressure source.Figure 10.29 (a) simple expansion chamber (b) simple expansion chamber, show...Figure 10.30 Transmission loss of simple expansion chamber [44–46]. ×, Plane...Figure 10.31 Flow‐reversing chamber with pass tube and end plate. c: distanc...Figure 10.32 Experimental system for measuring the transmission loss. A: fre...Figure 10.33 Transmission loss for SI‐SO flow‐reversing chamber (L = 2.0 in....Figure 10.34 Transmission loss for SI‐CO flow‐reversing chamber (L = 2.0 in....Figure 10.35 Transmission loss characteristics for SI‐SO muffler chambers: −...Figure 10.36 Transmission loss characteristics for SI‐SO muffler chambers: −...Figure 10.37 Predicted transmission losses for combination of SI‐CO flow‐rev...Figure 10.38 Transmission loss characteristics for combination of SI‐CO and ...Figure 10.39 Transmission loss characteristics for combination of SI‐CO and ...Figure 10.40 Transmission loss characteristics for combination of CI‐CO and ...Figure 10.41 Transmission loss for single expansion chamber with the Traditi...Figure 10.42 Transmission loss of muffler as a function of frequency: − − − ...Figure 10.43 Boundary element mesh for a simple expansion chamber muffler [8...Figure 10.44 TL for simple expansion chamber muffler in Figure 10.43: ——, BE...Figure 10.45 Sound pressure level (SPL) contour plot for the expansion chamb...Figure 10.46 Muffler model using the multidomain BEM [83].Figure 10.47 The SPL contour plot for multidomain muffler at 700 Hz [83].Figure 10.48 The transmission loss of the simple expansion chamber with leng...Figure 10.49 The transmission loss of the double expansion chamber with le =...Figure 10.50 Transmission loss for a short concentric tube resonator; ——, nu...Figure 10.51 Transmission loss for a long concentric tube resonator; ——, num...Figure 10.52 Transmission loss for a long concentric tube resonator with a f...Figure 10.53 Concentric tube muffler with a flow plug (L1 = 0.0317 m, L2 = 0...Figure 10.54 Comparison between the experimental data (−−−−) and the BEM pre...Figure 10.55 Comparison between the experimental data (−−−−) and the BEM pre...Figure 10.56 Muffler with two parallel perforated tubes (L1 = 0.0245 m, L2 =...Figure 10.57 (a) Comparison between the experimental data (−−−−) and the BEM...Figure 10.58 Transmission loss of a perforate muffler with flow plug [79]. ‐...Figure 10.59 Instrumentation for impedance measurements [53].Figure 10.60 (a) Specific resistance and (b) specific reactance of single or...Figure 10.61 Transmission loss for a short resonator: −−−−, predicted (solid...Figure 10.62 Transmission loss for a long resonator: −−−−, predicted (solid ...Figure 10.63 Effect of porosity on transmission loss for a short resonator, ...Figure 10.64 Resonator configuration [54].Figure 10.65 (a) The basic two‐duct element; (b) Branch point model of perfo...Figure 10.66 Transmission loss of resonator operating in (i) linear regime: ...Figure 10.67 Cross‐flow chamber configuration [54].Figure 10.68 (a) The basic three‐duct element; (b) control volume of jth bra...Figure 10.69 Transmission loss of cross‐flow chamber operating with (i) M...Figure 10.70 Theoretical insertion losses and transmission loss for an autom...Figure 10.71 Theoretical insertion losses and transmission loss for an autom...Figure 10.72 Insertion loss of an expansion chamber of the engine operating ...Figure 10.73 Radiated sound pressure level with the expansion chamber of the...Figure 10.74 (a) A sketch of a lined duct, showing the nomenclature used in ...Figure 10.75 Graph used to predict attenuation values.Figure 10.76 Normalized attenuation‐versus‐frequency curves for parallel‐baf...Figure 10.77 Normalized attenuation‐versus‐frequency curves for parallel‐baf...Figure 10.78 Attenuation of the fundamental mode in a rectangular duct with ...Figure 10.79 Attenuation of the fundamental mode in a rectangular duct with ...Figure 10.80 Predicted octave band attenuations for a rectangular duct lined...Figure 10.81 Predicted octave band attenuations for a rectangular duct lined...Figure 10.82 (a) Effect of varying the normalized flow resistance r0 d/Z0 on...Figure 10.83 Comparison of theoretical values with experiment for given baff...Figure 10.84 Attenuation rate for full unit silencer, (■) N1 = 5, (□) N1 = 2...Figure 10.85 Attenuation rate for full unit silencer, (■) R = 20, (□) R = 5,...Figure 10.86 Comparison between experimental and simulated data for silencer...Figure 10.87 Tested silencer: (a) sketch; (b) picture [143].

11 Chapter 11Figure 11.1 Terms used with gears: (a) involute gear, (b) meshing of two par...Figure 11.2 The main types of gear in use: (a) parallel axis (straight spur,...Figure 11.3 Gear noise energy flow diagram [16].Figure 11.4 Frequency spectrum for a gear pair having a 25‐tooth pinion rota...Figure 11.5 Bearing with spherical rolling elements [18].Figure 11.6 Sliding contact bearing [18].Figure 11.7 Main types of fans with descriptions of their use and design [18...Figure 11.8 Mechanisms of fan noise generation [31].Figure 11.9 Application of a quarter‐wavelength resonator for blower BPF noi...Figure 11.10 Typical sound pressure trace during the operation of a roll for...Figure 11.11 Comparison of the sound pressure level during cutting with and ...Figure 11.12 Effect of tip speed and gullet depth (d) on aerodynamic noise g...Figure 11.13 Slotted saw blade [63].Figure 11.14 One-octave band noise levels of saw blades. Overall A‐weighted ...Figure 11.15 Saw blade noise control [63].Figure 11.16 Smoothing of force–time history for helical vs. straight knife ...Figure 11.17 (a) Use of complete panel enclosure for molder noise and (b) us...Figure 11.18 Principles of operation of several positive‐displacement compre...Figure 11.19 Types of pumps: (a) kinetic pumps, (b) reciprocating pumps, and...Figure 11.20 Continuum continuous‐contact pumps feature helical gears that d...Figure 11.21 Laboratory tests that show reduced pulsation pressure (ripple) ...Figure 11.22 Laboratory measurements of the noise of two external gear pumps...Figure 11.23 Methods for reduction of pressure pulsating in pipes [76].Figure 11.24 Schematic representation of control valve noise generation and ...Figure 11.25 Basic aerodynamic A‐weighted sound pressure level in decibels f...Figure 11.26 Pump forces result as airborne noise (not shown) and (a) struct...Figure 11.27 Flame types in burners incorporating swirl [96].

12 Chapter 12Figure 12.1 Incident, reflected, and transmitted waves.Figure 12.2 Variation of mass law transmission loss of a single panel for so...Figure 12.3 Theoretical transmission loss of a single panel when panel mass,...Figure 12.4 Transmission loss of a single panel showing the effects of panel...Figure 12.5 Hemispherical area enclosing elemental panel area dS.Figure 12.6 Mass law transmission loss of a limp wall. The solid curves corr...Figure 12.7 Critical coincidence frequency fc plotted as a function of the t...Figure 12.8 Double‐panel system with an air gap of width d.Figure 12.9 Theoretical transmission loss for a double panel predicted by Lo...Figure 12.10 Design of double‐panel system: (a) straight‐through studs; (b) ...Figure 12.11 Transmission loss of double‐leaf and of single‐leaf gypsum boar...Figure 12.12 Wavenumber diagram for a simply‐supported beam.Figure 12.13 Wavenumber diagram for a simply‐supported plate.Figure 12.14 Wavenumber diagram for a hard‐walled rectangular room.Figure 12.15 Mode number counts for beam, plate and room.Figure 12.16 Modal densities for beam, plate and room.Figure 12.17 Spectral density of random force and square of admittance |Y|2 ...Figure 12.18 Modal overlap factor definition.Figure 12.19 A band of force and the resonance curves of the resonators that...Figure 12.20 (a) Sketch of a multi‐resonator system response |Y|2 to a broad...Figure 12.21 Simple plot of radiation efficiency of a simply‐supported panel...Figure 12.22 Radiation loss factor for a simply‐supported panel.Figure 12.23 Acceleration response of panel driven by a point force.Figure 12.24 (a) Partition panel wall connected to a room; (b) Power flow fr...Figure 12.25 Calculated sound pressure level in room.Figure 12.26 Block diagram showing power flow between two resonant systems l...Figure 12.27 Block diagram representing power flows between coupled systems ...Figure 12.28 Experimental values of transmission loss of 1/8 in. (3.175 mm) ...Figure 12.29 Transmission loss for a double aluminum panel, (panel thickness...Figure 12.30 Transmission loss for a double aluminum panel system of differe...Figure 12.31 Panel acceleration response relative to mass law. ○ experiment;...Figure 12.32 Transmission loss for a double aluminum panel with and without ...Figure 12.33 (a) The cab model split into its separate elements. (b) Power f...Figure 12.34 (a) Attenuation of a sealed box containing 1.2 m2 of absorbing ...Figure 12.35 Theoretical prediction of the attenuation of an idealized truck...Figure 12.36 Experimentally measured attenuation of the sealed model enclosu...Figure 12.37 Effect of optimization on TL (− − − before optimization, ——— af...Figure 12.38 Chart for determining the overall sound transmission loss, TL0,...Figure 12.39 Two common construction faults which allow direct air paths to ...Figure 12.40 Typical noise control measures for piping in buildings.Figure 12.41 Mechanical flanking paths.Figure 12.42 Schematic representation of a typical transmission suite.Figure 12.43 Schematic of the apparatus used to measure normal‐incidence TL ...Figure 12.44 A ¼‐in. (6.4 mm) glass sound transmission loss and STC contour;...Figure 12.45 Sound transmission through some common building materials: 100‐...Figure 12.46 Impact sound transmission measurement procedure.Figure 12.47 Examples of tapping machine levels [20]. The concrete slab is 1...Figure 12.48 Typical wall assemblies using gypsum boards: (a) Single 2 × 4 w...Figure 12.49 Typical Floor/Ceiling Assemblies: (a) Carpet and pad, 3/8″ part...Figure 12.50 A typical floating concrete floor construction of the type comm...Figure 12.51 Sound reduction index of floating floor [129].Figure 12.52 Recommended door seal designs.Figure 12.53 Examples of outdoor noise insulation provided by windows.Figure 12.54 Typical noise and vibration control techniques in a mechanical ...Figure 12.55 Typical wind velocity profiles in city and open country regions...Figure 12.56 Wind flow around a building. (a) section view and (b) plan view...Figure 12.57 Schematic diagram of airflow patterns around a bluff‐body or bu...Figure 12.58 Classification of dynamic effects from wind [137].Figure 12.59 Main types of wind‐induced oscillations: (a) vibration due to t...Figure 12.60 Telecommunications tower with mass distribution, stiffness dist...Figure 12.61 Fundamental frequency fe of tall buildings.Figure 12.62 Various types of damping [137].Figure 12.63 Friction dampers used in the load‐bearing structure of the now‐...Figure 12.64 Photographs of tuned mass damper (TMD) balls; (a) in Skyscraper...Figure 12.65 Human perception of building vibration due to wind.

13 Chapter 13Figure 13.1 Typical residential installation of heating, cooling, humidifyin...Figure 13.2 Typical residential installation of a split‐system air‐to‐air he...Figure 13.3 Typical residential installation of heating and cooling equipmen...Figure 13.4 Sources and paths of noise and vibration from a centrally locate...Figure 13.5 (a) Terminology used to describe HVAC system ductwork. (b) (1) g...Figure 13.6 Typical paths in HVAC systems [20]. 1: Structure‐borne path thro...Figure 13.7 Example of an air‐handling unit room with numerous acoustical an...Figure 13.8 The AHU with a greatly improved installation [25]. 1. Keeping a ...Figure 13.9 Frequency ranges of likely sources of sound‐related complaints [...Figure 13.10 Frequencies at which different types of mechanical equipment ge...Figure 13.11 Illustration of a typical HVAC sound spectrum for occupied spac...Figure 13.12 Components of a centrifugal fan.Figure 13.13 Exploded view of a typical axial‐flow fan.Figure 13.14 The three principal types of high‐efficiency centrifugal fans....Figure 13.15 Inline fan sound power level comparison [25]. ibid © ASHRAE Sch...Figure 13.16 A‐weighted sound power level test data for a typical plenum fan...Figure 13.17 Inlet and discharge octave band Lw values for a 925 mm plenum f...Figure 13.18 Sound power level comparison for three types of centrifugal fan...Figure 13.19 Inlet one‐octave band sound power levels Lw of three types of p...Figure 13.20 Sound power level comparison between two prediction methods for...Figure 13.21 Sound power level comparison between two prediction methods for...Figure 13.22 Guidelines for centrifugal fan installations [20]. Notes: 1. Sl...Figure 13.23 Vibration isolation suspension for propeller fans. Note: Positi...Figure 13.24 Noisy and quiet installation of ceiling‐mounted exhaust fans [2...Figure 13.25 Line diagram illustrating the major components of an HVAC syste...Figure 13.26 Guideline for VAV unit installation [25]. Note: Parallel or sid...Figure 13.27 This figure shows a set of curves giving guidance for the selec...Figure 13.28 Acoustical comparison of various building core area layouts [25...Figure 13.29 Mechanical room on ground floor of building. ibid © ASHRAE Scha...Figure 13.30 Very noisy rooftop unit installation [25]. ibid © ASHRAE Schaff...Figure 13.31 Very quiet rooftop installation [25]. ibid © ASHRAE Schaffer Gu...Figure 13.32 A typical floating concrete floor construction of the type comm...Figure 13.33 Floating floor vibration isolators‐molded precompressed glass f...Figure 13.34 Constructional details of floating floors at the base of dividi...Figure 13.35 Relationship between isolation efficiency, disturbing frequency...Figure 13.36 General machinery vibration amplitude severity chart (1 mil = 0...Figure 13.37 Isolation and support of concrete inertia bases from a mechanic...Figure 13.38 Structural support for vibration control of rooftop equipment [...Figure 13.39 A typical method used to provide horizontal restraint for a vib...Figure 13.40 Typical standing wave resonance as observed in a spring isolato...Figure 13.41 Length of flexible pipe connector required to give adequate vib...Figure 13.42 Duct and pipe penetrations through walls. Note: Support pipes a...Figure 13.43 All piping connections to a vibrating source should be resilien...Figure 13.44 Schematic representation of an acoustical plenum chamber.Figure 13.45 Schematic of end‐in/end‐out plenum.Figure 13.46 Speaking tube effect between adjacent rooms and possible soluti...Figure 13.47 Attenuation for lined and unlined sheet metal ductwork [25]. ib...Figure 13.48 Breakout transmission loss for three types of sheet metal ductw...Figure 13.49 In‐duct attenuation for various duct liner thicknesses [25]. ib...Figure 13.50 Variation of static pressure drop across a typical splitter‐typ...Figure 13.51 Construction of typical commercial silencers including a circul...Figure 13.52 Attenuation and noise generation characteristics of typical cyl...Figure 13.53 Duct silencer placement near a mechanical room wall [25]. ibid ...Figure 13.54 In‐duct attenuation of duct silencers and lined ductwork [25]. ...Figure 13.55 Comparative insertion loss of dissipative, film‐lined, and reac...Figure 13.56 Attenuation (dB) at duct termination due to end reflection loss...Figure 13.57 This shows the expected “end reflection” losses for rectangular...Figure 13.58 This shows the attenuation observed in mitre bends in ducts whe...Figure 13.59 Attenuation of rectangular elbows with and without turning vane...Figure 13.60 Attenuation of rectangular and radius elbows (lined and unlined...Figure 13.61 Velocity‐generated sound of duct mitre elbows [20]. Note: Compa...Figure 13.62 A‐weighted sound pressure levels measured 1.5 m (5 ft) from sur...Figure 13.63 (a) Proper and improper airflow condition to an outlet; (b) eff...Figure 13.64 Typical generated sound pressure levels vs. flow velocity for s...Figure 13.65 This figure can be used to estimate generated sound pressure le...Figure 13.66 The effect of installing a damper behind a grille; (a) Without ...Figure 13.67 The effect of partially closing a damper on a 50 cm × 50 cm (20...Figure 13.68 Velocity‐generated sound of 60 cm by 60 cm volume damper [20]. ...Figure 13.69 If possible, dampers should be placed well back behind outlet g...Figure 13.70 Duct breakout.Figure 13.71 Duct breakin.Figure 13.72 Typical radiated sound power levels for dual‐inlet mixing boxes...Figure 13.73 Effect on radiated sound power level of applying a layer of 1/6...Figure 13.74 HVAC systems for an office block. Dimensions are in mm.

14 Chapter 14Figure 14.1 Location of sources of power plant, tire, and wind noise on an a...Figure 14.2 A‐weighted vehicle sound pressure level, SPL, at constant speeds...Figure 14.3 Exterior sound pressure level, SPL, of a Volvo F12 truck under d...Figure 14.4 Comparison of A‐weighted radiated sound power level for a stiff ...Figure 14.5 Definitions of muffler performance.Figure 14.6 View of finished CPX trailer built at Auburn University [20].Figure 14.7 A‐weighted one‐third octave band sound pressure level tire/road ...Figure 14.8 Some locations of sound sources on an automobile body. Type (a) ...Figure 14.9 Locations in a typical automobile where damping treatments are o...Figure 14.10 A‐weighted sound pressure levels obtained during stationary eng...Figure 14.11 Wind noise at driver's ear location and speed of 180 km/h in ve...Figure 14.12 Dashboard panel made of laminated vibration damped steel [40]....Figure 14.13 Typical locations in an automobile where “barrier” materials ar...Figure 14.14 Typical locations in an automobile where sound‐absorbing materi...Figure 14.15 Operator cabin of an agricultural harvester machine [72].Figure 14.16 Measured and predicted agricultural cabin sound insertion loss ...Figure 14.17 Noise and vibration sources in a railroad car [88].Figure 14.18 Interior sound pressure level as a function of train speed, V [...Figure 14.19 Comparison of floor vibration levels for solid wheel and low‐no...Figure 14.20 Comparison of interior noise levels for solid wheel and low‐noi...Figure 14.21 Source/path acoustical model [98].Figure 14.22 Percentage of passengers choosing various criteria needing impr...

15 Chapter 15Figure 15.1 Dominant turbofan engine noise sources [4].Figure 15.2 Noise levels and spectra of general aviation aircraft [7].Figure 15.3 Sound pressure level spectrum for typical cabin noise in a turbo...Figure 15.4 Main rotor head kinematics [11].Figure 15.5 Stacked constrained layer damper system [15].Figure 15.6 Interior of fuselage skin showing pockets between the stringers ...Figure 15.7 Use of constrained layer damping with an aircraft stringer [15]....Figure 15.8 Active control of aircraft interior noise: (a) active noise cont...Figure 15.9 Certification limits for aircraft [38].

16 Chapter 16Figure 16.1 Synthesis of all the clustering survey results. The mean of the ...Figure 16.2 Percentage highly annoyed persons (%HA) as a function of DNL. Tw...Figure 16.3 A‐weighted sound pressure levels of cars and light and heavy tru...Figure 16.4 Cruise‐by exterior A‐weighted sound pressure levels measured at ...Figure 16.5 Measurement positions used for cruise‐by or acceleration noise tests.Figure 16.6 Noise levels and spectra of wide‐body fanjet aircraft (e.g. the ...Figure 16.7 Measurement locations for certification testing of aircraft to F...Figure 16.8 Predicted values of the attenuation provided by a 1 m wide earth...Figure 16.9 Definition of four zones according to a city plan and the corres...Figure 16.10 Typical noise contours for an airport [44].

Engineering Acoustics

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