Diffuse sound fields, reverberation-room methods and the effectiveness of reverberation-room designs
department or school: Applied Science, Faculty of
department or school: Mechanical Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Hasan, Md Mehadi
issued: 2015-10-24T03:05:10
issued: 2015
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: The reverberation-room method, which assumes a diffuse sound field, has long been used for various standardized room-acoustical determinations – e.g. of surface-absorption coefficients, power levels of sound sources, transmission losses of acoustical partitions, etc. In this regard, a number of standards have emerged to offer some help by outlining necessary reverberation-room design guidelines to achieve sufficient sound-field diffuseness. However, unsatisfactory opinions regarding the prediction accuracy of the method, especially at low frequencies, have been reported over the years. This might be due to deviations from the assumed diffuse-field concept, which is very challenging to implement from an application point of view; also there are no straight-forward ways to characterize the degree of sound-field diffuseness. To investigate the problem and propose solutions, diffuse-field theory and existing standards have been revisited. Using numerical, finite-element-based, modal prediction, their capacity/effectiveness to achieve a diffuse sound field is analyzed by means of a number of descriptors (room-acoustical parameters). Because of time limitations, the concept regarding the design of a reverberation-room structure – i.e. size, shape, etc. – is mainly explored, rather than the internal test-setup arrangements. The prediction accuracy of different room-acoustical parameters are also determined by the reverberation-room standard methods, with respect to both the Sabine and Eyring versions of the diffuse-field formulae, and both in octave and third-octave bands. The minimum approachable frequencies of predictions and the quality of sound-field diffuseness are discussed in terms of the prediction accuracy of different room-acoustical parameters. Considering three room volumes prescribed by standards, and four room shapes for each of the volumes, it has been found that the reverberation room of volume 150 m³, as prescribed by the ISO 354 standard, with the typical…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/54830
note: Diffuse Sound Fields, Reverberation-Room Methods and the Effectiveness of Reverberation-Room Designs by Md Mehadi Hasan B.Sc., Bangladesh University of Engineering and Technology, Bangladesh, 2012 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) September 2015 © Md Mehadi Hasan, 2015 ii Abstract The reverberation-room method, which assumes a diffuse sound field, has long been used for various standardized room-acoustical determinations – e.g. of surface-absorption coefficients, power levels of sound sources, transmission losses of acoustical partitions, etc. In this regard, a number of standards have emerged to offer some help by outlining necessary reverberation-room design guidelines to achieve sufficient sound-field diffuseness. However, unsatisfactory opinions regarding the prediction accuracy of the method, especially at low frequencies, have been reported over the years. This might be due to deviations from the assumed diffuse-field concept, which is very challenging to implement from an application point of view; also there are no straight-forward ways to characterize the degree of sound-field diffuseness. To investigate the problem and propose solutions, diffuse-field theory and existing standards have been revisited. Using numerical, finite-element-based, modal prediction, their capacity/effectiveness to achieve a diffuse sound field is analyzed by means of a number of descriptors (room-acoustical parameters). Because of time limitations, the concept regarding the design of a reverberation-room structure – i.e. size, shape, etc. – is mainly explored, rather than the internal test-setup arrangements. The prediction accuracy of different room-acoustical parameters are also determined by the reverberation-room standard methods, with respect to both the Sabine and Eyring versions of …
has type: Thesis/Dissertation
date issued: 2015-11
is shown at: 10.14288/1.0165807
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
rights URI: http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/54830