% IMPORTANT: The following is UTF-8 encoded. This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.
@PHDTHESIS{Berzborn:1015825,
author = {Berzborn, Marco},
othercontributors = {Vorländer, Michael and Fernandez Grande, Efren},
title = {{M}easurement and quantification of directional sound field
decay},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-06560},
series = {Aachener Beiträge zur Hörtechnik und Akustik},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2025},
abstract = {The random-incidence absorption coefficient is measured in
a reverberation room as per ISO354:2003 (2003), assuming a
diffuse and isotropic sound field. However, reproducibility
issues across different laboratories suggest that the
assumption of isotropy does not hold in practice. This
dissertation presents a novel experimental method for
capturing and analysing the directional characteristics of
energy decay in reverberation rooms. The method involves
decomposing the sound field into plane waves using
microphone arrays. Using Schroeder integration, the newly
introduced directional energy decay curve (DEDC) is
calculated on the time dependent angular plane waves density
function. The DEDC is decomposed into spherical harmonics,
which are used to formulate time-dependent estimators for
isotropy and axial symmetry. The estimators are formulated
by leveraging the symmetry relationships of spherical
harmonics and offer high temporal and angular resolution.
The DEDC framework further enables the analysis of
directionally non-uniform damping of the sound field. An
inverse problem is formulated using the DEDC framework and a
stochastic model for directionally dependent energy decay.
Variational inference is utilized to identify the model
parameters and provide uncertainty measures. Experimental
results obtained in a reverberation room in four
configurations are presented. These configurations include
the room with and without a highly absorptive glass wool
specimen, and both configurations additionally with and
without panel diffusers. The findings reveal non-isotropic
sound fields, particularly in the presence of the absorbing
specimen. It is shown that sound field isotropy varies over
time, decreasing in configurations for which non-uniform
distributions of damping are identified. Finally, the
relationship between the symmetry quantification results and
the errors in the random-incidence absorption coefficient is
explored using a statistic model. Combined factor analysis
and linear regression models reveal a statistically
significant relationship between the estimators and the
absorption coefficient error. The results further suggest
that the model is capable of correcting the measured
absorption coefficient if data from multiple laboratories
are available.},
cin = {613510},
ddc = {621.3},
cid = {$I:(DE-82)613510_20140620$},
pnm = {DFG project G:(GEPRIS)298797807 - Theoretische und
experimentelle Analyse der Diffusität in Raumschallfeldern
(298797807)},
pid = {G:(GEPRIS)298797807},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
doi = {10.18154/RWTH-2025-06560},
url = {https://publications.rwth-aachen.de/record/1015825},
}
guest ::