Timbre is that property of a sound that distinguishes it other than pitch and loudness, for instance the distinctive sound quality of a violin or flute. While the term is obscure, the concept has played an important, implicit role in recent philosophy of sound. Philosophers have debated whether to identify sounds with properties of waves, events, or objects. Many of the intuitive considerations...

This paper discusses the propagation of sound waves in air, specifically in narrow rectangular pathways of an occluded-ear simulator for acoustic measurements. In narrow pathways, both the speed of sound and the phase of the sound waves are affected by the damping of the air viscosity. Herein, we propose a new finite-element method (FEM) that considers the effects of the air viscosity. The meth...

The interference of the direct wave from the point source to the receiver and the wave reflected from the impedance ground in a turbulent atmosphere is studied. A parabolic equation approach for calculating the sound pressure p at the receiver is formulated. Then, the parabolic equation is solved by the Rytov method yielding expressions for the complex phases of direct and ground-reflected wave...

Along with the strong movement towards sustainable urban environments, there is an increasing use of green roof systems, including the semi-extensive green roofs, which are composed of lightweight layers of freedraining material that support low-growing, tough, and drought-resistant vegetation. Various kinds of green roof systems are also used at street levels, on the top of underground car par...

2014 Resonant scattering of sound by finite physical structures is considered as a possible means of producing bistability in diffusion of sound waves. Nonlinear dependence of the sound propagation velocity upon the sound intensity is needed in order to provide proper conditions for the insurgence of bistability. Multistability behaviour is considered as a possibility in the concurrence of prop...

Membrane-type acoustic metamaterials are well known for low-frequency sound insulation. In this work, by introducing a flexible piezoelectric patch, we propose sound-insulation metamaterials with the ability of energy harvesting from sound waves. The dual functionality of the metamaterial device has been verified by experimental results, which show an over 20 dB sound transmission loss and a ma...

This paper proposes several algorithms to compute the 3D sound-field in complex environments. The basic idea is to explore the similarities of light and sound propagation and take advantage of efficient rendering algorithms and hardware to compute the sound field. First we consider only the direct effect of sound sources. Then single reflections of the sound are also computed using the analogy ...

In this chapter, we study the solutions, both analytical and numerical, to the two most important equations of one-dimensional continuum dynamics. The heat equation models the diffusion of thermal energy in a body; here, we analyze the case of a one-dimensional bar. The wave equation describes vibrations and waves in continuous media, including sound waves, water waves, elastic waves, electroma...