Sound concentration caused by curved surfaces

Vercammen, Martijn

doi:10.1121/1.4800250

Cited by 10 publications

(4 citation statements)

References 13 publications

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“…This approach is sufficiently accurate in areas that are not close to the possible focal points; however, the accurate modeling of the sound pressure at the focus requires the use of wave-based modeling. 48 In certain GA methods, such as ray tracing, there is no need for the explicit tessellation of curved surfaces; instead, an IS solution can be locally applied at each point of the surface. In practice, this requires that the surface is represented in such a form that the intersection of a ray and the surface, and the corresponding reflection, can be efficiently computed.…”

Section: Curved Surfacesmentioning

confidence: 99%

Overview of geometrical room acoustic modeling techniques

Savioja¹,

Svensson

2015

The Journal of the Acoustical Society of America

287

190

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Computerized room acoustics modeling has been practiced for almost 50 years up to date. These modeling techniques play an important role in room acoustic design nowadays, often including auralization, but can also help in the construction of virtual environments for such applications as computer games, cognitive research, and training. This overview describes the main principles, landmarks in the development, and state-of-the-art for techniques that are based on geometrical acoustics principles. A focus is given to their capabilities to model the different aspects of sound propagation: specular vs diffuse reflections, and diffraction.

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Section: Curved Surfacesmentioning

confidence: 99%

Overview of geometrical room acoustic modeling techniques

Savioja¹,

Svensson

2015

The Journal of the Acoustical Society of America

287

190

View full text Add to dashboard Cite

show abstract

“…Due to a limited amount of available energy and the simultaneous absence of a built enclosure, acoustic diffusion and convex shapes need to be avoided. Vice-versa energy concentration has to be pursued, stressing the importance of an accurate control over concave shapes, so that acoustic focus phenomena are excluded 12 . A close interrelation between the GA research behavior and the definition process of the final shell surfaces was noticed.…”

Section: Discussionmentioning

confidence: 99%

Sound-Strength Driven Parametric Design of an Acoustic Shell in a Free Field Environment

et al. 2014

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Focusing on the issues of sound propagation in a free field condition and on the concept of uniform sound energy in an outdoor performance environment, our research aimed to develop a computer-aided process for the generation of reflective acoustic surfaces to be used as concert-shells, a computational design tool for acoustic form-finding. The project is ultimately aimed to investigate the acoustic potential of complex and doublycurved surfaces through the analysis of the Total Relative Sound Level / Strength parameter (G), with reference to the proposed values set by M.Barron, based upon the source-receiver distance and the subsequent subjective judgments on loudness. A simplified and fast ray-tracing acoustic simulation algorithm was developed in combination with parametrically controlled shape variations of the reflective surfaces. Sound energy uniformity evaluation function considering the direct and reflected sound components was written in order to define and evaluate the rate of distribution uniformity of sonic energy over an audience. This evaluation function was used in a genetic algorithm that enabled us to explore a wide set of surface morphologies which allowed us to isolate the fittest one to our specific uniformity requirements. At the end of the genetic search, an acoustic simulation plug-in called Pachyderm was employed with both NURBS and mesh-based acoustic simulations in order to validate the genetically selected surfaces with specific reference to G values. A further step of resultant data visualization and human selection was necessary to compare the output data and to evaluate the final surfaces from an architectural perspective. 32 Sound-Strength Driven Parametric Design of an Acoustic Shell in a Free Field Environment

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“…Cops et al 10 described the measurement of the absorption coefficient of different types of absorbing materials with totally different absorption performances, taking into account the influence of equipment control, source and microphone positions, diffuser versus diffusivity, the position of the absorbing material within the room, and the change in configuration of the reverberation room. Vercammen 11 pointed out the insufficient diffuse sound field in a reverberation chamber when a highly absorbing test sample is inside; the shape of the reverberation room and the placing of diffusers do influence the result. Mee and Vallis 12 present an analysis about the importance of diffusion levels and the effects of diffuser panels on the variations in the sound field in rooms.…”

Section: Introductionmentioning

confidence: 99%

Using Sabine’s and sound power relation to study: The effect of diffusers on measured sound absorption

Mahmoud,

Shawky

2024

Building Acoustics

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The purpose of this study is to evaluate the effect of the number of diffusers placed in the same room, as well as the effect of diffusers with a flat area (8.4, 13.2, and 18 m2) on the calculated sound absorption coefficient in a reverberation room, when an iterative procedure based on the evaluation of the sound power level is applied (this is done by using the sound power equation and substituting with different values of equivalent absorption area on both sides of the transformed equation to reach the correct value for absorption area, which achieves equality on both sides of the equation in order to achieve the goal). The sound absorption coefficient at random incident of three materials having different degrees of absorption—has been measured in a reverberation room according to ISO 345: a highly absorbent material (sponge) a medium absorbent material (rubber) and a low absorbent material (wood).There is a noticeable convergence between the calculated and measured sound absorption coefficient from the usual ISO 354 procedure and from the sound power level equation from ISO 3741,when diffusers are present. The difference in sound power level is close to 1.0 dB depending on the position of the source with the diffuser area. Thanks to the diffusers effect, the difference between the measured and the calculated sound absorption coefficient can be considerably reduced.

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Sound concentration caused by curved surfaces

Cited by 10 publications

References 13 publications

Overview of geometrical room acoustic modeling techniques

Overview of geometrical room acoustic modeling techniques

Sound-Strength Driven Parametric Design of an Acoustic Shell in a Free Field Environment

Using Sabine’s and sound power relation to study: The effect of diffusers on measured sound absorption

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