Acoustics: Sound Fields and Transducers
Language: English
Pages: 720
ISBN: 0123914213
Format: PDF / Kindle (mobi) / ePub
Acoustics: Sound Fields and Transducers is a thoroughly updated version of Leo Beranek's classic 1954 book that retains and expands on the original's detailed acoustical fundamentals while adding practical formulas and simulation methods.
Serving both as a text for students in engineering departments and as a reference for practicing engineers, this book focuses on electroacoustics, analyzing the behavior of transducers with the aid of electro-mechano-acoustical circuits. Assuming knowledge of electrical circuit theory, it starts by guiding readers through the basics of sound fields, the laws governing sound generation, radiation, and propagation, and general terminology. It then moves on to examine:
- Microphones (electrostatic and electromagnetic), electrodynamic loudspeakers, earphones, and horns
- Loudspeaker enclosures, baffles, and waveguides
- Miniature applications (e.g., MEMS in I-Pods and cellphones)
- Sound in enclosures of all sizes, such as school rooms, offices, auditoriums, and living rooms
Numerical examples and summary charts are given throughout the text to make the material easily applicable to practical design. It is a valuable resource for experimenters, acoustical consultants, and to those who anticipate being engineering designers of audio equipment.
- An update for the digital age of Leo Beranek's classic 1954 book Acoustics
- Provides detailed acoustic fundamentals, enabling better understanding of complex design parameters, measurement methods, and data
- Extensive appendices cover frequency-response shapes for loudspeakers, mathematical formulas, and conversion factors
What a Wonderful World: One Man's Attempt to Explain the Big Stuff
Science: The Definitive Visual Guide
Encyclopedia of Psychopharmacology (2nd Edition)
2.2 Derivation of the wave equation 25 Let P ¼ P0 þ p; V ¼ V0 þ s; (2.8) where P0 and V0 are the undisturbed pressure and volume, respectively, and p and s are the incremental pressure and volume, respectively, owing to the presence of the sound wave. Then, to the same approximation as that made preceding Eq. (2.4) and because p << P0 and s << V0, p gs ¼ À : P0 V0 (2.9) 1 dp g ds ¼ À : P0 dt V0 dt (2.10) The time derivative of this equation gives 2.2.3 The continuity equation The
the wave equation for a spherical wave. PART IV: SOLUTIONS OF THE WAVE EQUATION IN ONE DIMENSION 2.3 GENERAL SOLUTIONS OF THE ONE-DIMENSIONAL WAVE EQUATION The one-dimensional wave equation was derived with either sound pressure or particle velocity as the dependent variable. Particle displacement, or the variational density, may also be used as the dependent variable. This can be seen from Eqs. (2.4a) and (2.13a) and the conservation of mass, which requires that the product of the density and
the schematic diagram is u~2 ¼ f~2 ¼ 1 1 1 1 þ þ 1=juMM2 GM2 juCM 1 juMM2 þ RM2 þ 1 juCM : Including the element GM1 the mechanical admittance for that part of the circuit through which f~2 flows is, then, u~ ¼ GM1 þ ~ f2 juM M2 ~ f u~ ~ f2 þ RM2 þ 1 juCM : GM1 ~ f1 MM1 1 MM2 GM2 CM FIG. 3.17 Admittance-type analogous circuit for the device of Fig. 3.15. u~2 3.3 Mechanical elements 81 Note that the input mechanical admittance YM is given by YM ¼ u~ u~ : þ f~ f~1 þ f~2 and
the diagonal. That is, z12 ¼ z21. However, we shall see that in the case of an electromagnetic-mechanical transducer, it turns out to be skew-symmetrical, that is with z12 ¼ Àz21, because det(A) ¼ À1, which in turn is due to the fact that the current flow in a wire resulting from movement through a magnetic field is in the opposite direction to that producing the same movement (Fleming’s generator rule versus motor rule). The reverse transformation equations are of the same form: a11 ¼ z11 =z21 ;
based on existing product range Care should be taken that a screen is tensioned before it is fitted. Otherwise it will not behave as a pure resistance, but more like a membrane with compliance. If it is too slack, its motion will be nonlinear. The acoustic resistances pffiffiof screens are generally determined pby ffiffiffi test and not by calculations. Tube of small diameter [0.0005 l < radius a ( in meters) < 0.002/ f ]. As derived in Par. 4.22, the acoustic impedance of a tube of very small diameter,
