Acoustic Reflection from a Plane Boundary Having Variable Surface Parameters
Acoustic Reflection from a Plane Boundary Having Variable Surface Parameters

Author:

Publisher:

Published: 1991

Total Pages: 19

ISBN-13:

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A possible technique for studying the acoustic reflection from continuous plane surfaces such as flat plates covered with thin anechoic coatings is discussed. It is particularly directed to complex coatings which include a regular array of non-homogeneous inclusions within their structures. The method involves the experimental determination of a position-dependent quantity which can be viewed as either a surface transfer admittance or a surface transfer mobility function. This function can then be used in a mathematical convolution procedure to determine the nature of the reflected wave from the surface when it is ensonified by an incident uniform plane wave arriving in a direction normal to the plate surface. The basic theory behind the proposed method is presented for a surface having a periodic, two-dimensional spatial variation. As a side issue, this approach raises a question as to the applicability of an 'average surface admittance' approach used previously to estimate reflection coefficients of Alberich coatings. The basic elements of an experimental system for measuring the surface admittance functions are discussed.

Acoustic Absorbers and Diffusers
Acoustic Absorbers and Diffusers

Author: Trevor J. Cox

Publisher: CRC Press

Published: 2009-01-26

Total Pages: 495

ISBN-13: 0203893050

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Absorbers and diffusers are two of the main design tools for altering the acoustic conditions of rooms, semi-enclosed spaces and the outdoor environment. Their correct use is important for delivering high quality acoustics. Unique and authoritative, this book decribes how to effectively measure, model, design and apply diffusers and absorbers. It is a resource for new and experienced acousticians, seeking an understanding of the evolution, characteristics and application of modern diffusers. Absorption is a more established technology and so the book blends traditional designs with modern developments. The book covers practical and theoretical aspects of absorbers and diffusers and is well illustrated with examples of installations and case studies. This new edition brings Acoustic Absorbers and Diffusers up-to-date with current research, practice and standards. New developments in measurement, materials, theory and practice since the first edition (published in 2004) are included. The sections on absorbers are extended to include more about noise control.