Building Acoustics

359

Subject index

Absorber
membrane, 156, 157, 176
microperforated, 158, 174
porous, 156
resonator, 156
Absorbing area, 113
Absorption exponent, 121, 146
Absorption factor, 60, 70
statistical, 80, 186
Absorption length, 350
Absorption, 190
Acoustical lining, 286
AD-converter, 14
Air absorption, 122
Airflow resistance, 169
Airflow resistivity, 60, 196
Aliasing, 16
Anisotropy, 89
Apparent mass, 37
Attenuation coefficient, 60
Auralization, 144
Autocorrelation function, 22, 24
A-weighting, 214

Base band analysis, 19
Bending waves, 55
Biot theory, 178
Break-in, 332
Break-out, 332
Bulk modulus, 82, 190

Characteristic impedance, 58
Chirp signals see Swept sine signals
Coefficient of viscosity, 190
Coherence function, 34
Coincidence frequency see Critical
frequency
Compliance, 294
Consistency relation, 269
Convolution, 144
Critical damping, 40
Critical frequency, 223, 293

Cross correlation, 35

Cross spectrum see Cross spectral

density function

Cross spectral density function, 35

Damping

coefficient, 40, 320

critical, 320

Damping controlled, 43

Damping ratio, 40

Definition, 109

Degree of freedom, 48

Density

equivalent, 190

Diffuse field, 117

Diffusion coefficient, 138

Dirac δ-function, 9

Dirac pulse, 330

Directivity factor, 67, 124

Directivity pattern, 67

Discrete Fourier transform (DFT), 14

Double wall, 277, 295

heavy, 296

resonance, 280, 304

Double leaf partition, 290

Driving point impedance, 37

Duct system, 332

Dynamic stiffness, 317

Early decay time, 107

Early-to-late index, 108

Edge effect, 159, 183

Edge losses, 100

Efficiency, 47

Eigenfrequency, 40, 52

Eigenfunctions, 52, 84

Eigenmode see Natural mode

End correction, 167, 171

Energy density, 118

Energy spectral density, 9

Ensemble, 12

Equipartition of energy, 267