Eigenmodes in Nonrectangular Reverberation Rooms

Nieuwland, J. M. van; Weber, Carl Maria von

doi:10.3397/1.2832132

Cited by 11 publications

(3 citation statements)

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“…However, these alterations make the low-frequency performance much more difficult to predict when compared to the performance of a rectangular space. 27,28 Changes to the geometry of a room do not eliminate modal effects on the sound field and listening responses: they simply make them harder to predict. 29 When attempting to predict modal behaviour of the space, it should be noted that non-rectangular spaces do not follow the simple formulation of eigen-frequencies that rectangular spaces do.…”

Section: Introductionmentioning

confidence: 99%

Effects of absorption placement on sound field of a rectangular room: A statistical approach

Lau

Powell

2018

Journal of Low Frequency Noise, Vibration and Active Control

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Room resonances create dramatic fluctuations in the distribution of sound pressure throughout the listening region of a room. Previous studies indicate that the addition of sound absorbing material decreases room resonances and shifts its modal characteristics. The present study proposes an approach which qualifies the effects that the additional absorption in a listening room may have on the sound fields and the frequency responses. Finite element analysis was employed for modelling the low-frequency responses of a room. The study analyses frequency responses at various listening positions involving different amounts and different placement of sound absorbents on room surfaces by observing standard deviation for linearity across a chosen frequency range. Two-dimensional sound field plots at listening height were also used to examine the spatial changes of room resonances caused by the additional absorption. The present study applied a modified statistical approach to evaluate both the sound field and the frequency responses of a room. The results were then applied to re-evaluate the effects of the absorbers location on the listening region through the proposed approach.

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Section: Introductionmentioning

confidence: 99%

Effects of absorption placement on sound field of a rectangular room: A statistical approach

Lau

Powell

2018

Journal of Low Frequency Noise, Vibration and Active Control

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“…The determination of the modal parameters in the most general case of non-rectangular rooms requires one of the more complex methods, such as the use of the finite element method [8].…”

Section: Introductionmentioning

confidence: 99%

Adaptive Control of Low-Frequency Acoustic Modes in Small Rooms

Bistafa

Hodgkin²,

Morita³

et al. 2012

TOACOJ

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The work presents the implementation in software of an adaptive method for reducing the non-uniformity of the frequency-response-curve, by covering certain walls of small rectangular rooms, with a particular type of a passive acoustical treatment, consisting of porous absorbents covered with perforated sheets, in which each perforation behaves independently as Helmholtz resonators. The method employs new developments of another publication for finding the modal parameters, namely natural frequencies and associated damping constants, of rectangular rooms with arbitrary (uniform) wall-impedances. The adaptive software is capable of continuously improving the implemented type of acoustical treatment and would allow the implementation of new types of treatments as desired. Some testing results are presented, demonstrating the ability of the software for finding best parameters of the acoustical treatment, giving as input data the room dimensions and source/receiver locations only.

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“…(B)Modo 3,1,0 da sala retangular (81,1Hz) comparado com a sala não retangular(35,5Hz) (C) Modo 0,4,0 da sala retangular (98Hz) comparado com a sala não retangular (95,3Hz) (D)Modo 3,0,0 da sala retangular (102,9Hz) comparado com a sala não retangular (103,9Hz)3.2.13.4 Modos normais em salas não simétricasNieuwland eWeber (1979) realizaram pesquisas sobre câmaras reverberantes no Philips Research Laboratories of Eindhoven, nos Países Baixos e concluíram que em salas não retangulares, a estrutura espacial do nível de pressão sonora dos modos é irregular. A sobreposição dos diferentes modos resultará favoravelmente em uma menor variação de pressão nas salas irregulares(EVEREST, 1988b, p. 52).…”

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Design de difusores sonoros a partir de processo serial

Mannis¹

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A colegas, amigos e parentes que incentivaram e contribuíram para que este trabalho se realizasse com sucesso Ao Todo, pela luz e pelo aprendizado. Areas of knowledgeArts (Music); Applied Social Sciences (Architecture and Urbanism (Environmental Adequacy)); Hard Science (Physics (Acoustics)); Engineering (Civil Engineering(Construction Engineering, Building Acoustics)) Domaines de la connaisance Arts (Musique); Sciences Sociales Appliquées (Architecture et Urbanisme (Adéquation de l'environnement)); Sciences Exactes (Physique (Acoustique)); Génie (Génie Civil (Construction, Acoustique)) ERRATA: p. 164 -1º parágrafo, 3ª linha: o que equivale a uma atenuação de 1,55 dB Palavras-chave

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Eigenmodes in Nonrectangular Reverberation Rooms

Cited by 11 publications

References 2 publications

Effects of absorption placement on sound field of a rectangular room: A statistical approach

Effects of absorption placement on sound field of a rectangular room: A statistical approach

Adaptive Control of Low-Frequency Acoustic Modes in Small Rooms

Design de difusores sonoros a partir de processo serial

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